Cuban AgroEcology Tour: La Palma farm, Pinar del Rio Province
Here’s another post about the Organic Growers School Agroecolgy Tour I participated in back when we could travel! I feel so fortunate to have made this trip this January. You can read about other parts of this Tour under the Cuban Agriculture category or at these links:
After our initial stay in Havana, we traveled west for three hours to stay a few days in the Viñales Valley in the province of Pinar del Rio.
Day 5 – Saturday January 11, morning
Our day started with an 8 am breakfast at our casa particulare in Viñales. We enjoyed fruit, tea, coffee, juice, cookies, bread, pancakes, cheese sandwiches, and ham. No eggs today.
We took our tour bus to visit the ANAP (National Association of Small Farmers) cooperative agricultural project La Palma. ANAP farmers have less than 67 hectares each. According to Wikipedia, currently ANAP members produce 52% of the vegetables, 67% of the corn, and 85% of the tobacco grown in Cuba.
We met tobacco producers Roberto and Eduardo, who are brothers. Each farm is allowed a certain tobacco quota by the Cuban government. They are growing 40,000 tobacco plants as their quota and another 40,000 using a neighbor’s irrigated land in trade for their use of some dry land. Tobacco needs irrigated land, and their neighbor did not have the other resources to grow a tobacco crop this year. The government agreed to this swap because of the poor state of the national economy.
La Palma also grows vegetables (tomatoes, beans with some interplanted corn plants to protect the beans from pests), and cassava. They use oxen for cultivating the fields. We had some juice, a taste of red mamey fruit (Pouteria sapota), and the chance to buy cigars for $2 each.
Next we paid a visit to a farm with a small cigar manufacturing business, Manolo Tobacco Farm, for a demonstration of cigar-making, and a chance to buy different kinds of cigars. All the cigars are rolled by hand and the men demonstrating the technique are also professional in engaging the audience. After rolling a cigar for us, the demonstrator lit it, showed how to smoke cigars and passed it round.
See this video of cigar making at Manolo Tobacco Farm, made by Franny’s Farmacy, two of the other people on my Organic Growers School Tour:
At this place I was dismayed to find a nasty toilet (not the first of this trip): no seat, no paper, no flush. The toilet tank was not connected to a water supply. The water at the sink was very slow, and even though a bucket was provided, filling it to flush the toilet seemed very challenging. How can a tourist attraction have such terrible toilets? Why are there not more composting toilets?
Cuba, at least in the northwest, suffers from a shortage of water, and ancient mainline plumbing that leaks a lot. When we arrived at the José Martí International Airport in Havana, an announcement came over the loudspeaker that the water supply had been temporarily shut off to the restrooms. Havana has a natural port, but no river drains into it. See Rivers in Cuba map to appreciate the unfortunate geography!
The Albear Aqueduct was constructed in Havana in 1858, in a neoclassical style and still supplies 20% of Havana’s water. A marvel of mid-19th century engineering, the water comes from the de Vento springs by gravity. This fresh water helped the city reduce the terrible cholera epidemics and earned a gold medal at the 1878 Paris Exposition
Book Review: Grow Great Vegetables in Virginia, by Ira Wallace, Timber Press, 2020. 240 pages, line drawings and full color photos, $19.95.
Here is a great book for beginning gardeners or those new to Virginia. Ira’s friendly style will encourage everyone wanting to grow their own food, whether you’re one of the new “Covid Victory Gardeners”, newly retired from your day job, or newly determined to eat better food, this book will help you towards success. There are not many authors who could write five books at once, but Ira has given us five regional books for the southeast, with more details than her earlier Timber Press Guide to Vegetable Gardening in the Southeast. She has written for gardeners in Georgia, Tennessee, North and South Carolina.
I’m reviewing the Virginia book, which includes an introduction to Virginia, to gardening and to garden planning. Most of the book is a series of month-by-month lessons on what to plant; what you could be harvesting; and seasonal topics. The harvest lists are very encouraging! 11 crops in January, 27 in July, 46 in October. And there are the stored crops too. I like the month-by-month format. It enables new gardeners to learn just enough for each month’s tasks, and get ready to learn something new.
There’s a map of Virginia and the winter-hardiness zones, and at the back of the book there’s a chart of the average coldest temperatures in each of the zones. I wished for a heat zones map as well, because climate is not only about winter temperatures. Summer weather has quite an impact too! There are good descriptions of the growing season in various regions of Virginia, and the kinds of weather that come our way.
In the gardening intro, there is a table of organic sources of plant nutrients; encouragement to try succession planting (making several sowings over the course of the growing season to keep fresh supplies of that vegetable rolling in); and an explanation of planting “hills” (which might be better flat when it’s hot and dry). I remember being new in this country and not understanding hills at all, because books didn’t explain what they are, why you might use them, or how far apart they are. I proceeded to plant in rows, as I had done in England, and the crops grew fine. Eventually I learned what hills are. They’re not essential, and not necessarily better than rows, but maybe good for small home gardens. Read Ira’s book! She explains her information clearly, and her reasons for doing things the way she does. She explains why we transplant in the afternoon on an overcast or drizzly day. We live in a climate with hot summers, we don’t transplant in the mornings!
In the planning section, there is a full-page chart classifying vegetable crops as easy-to-grow, slightly more challenging and (undeniably) challenging. Each category is subdivided into warm season, cool season and “in need of extra space”, so no one need waste time on monstrous crops at the wrong time of year. Many paths to failure eliminated! There is encouragement to weigh up the value of keeping an old tomato planting going, versus getting a winter cover crop planted. Growing food well involves not forming attachments to particular plants! Ira says you can more than double the yield in a small garden by having some transplants ready to pop into any spaces that open up.
Planning includes being prepared for surprise opportunities to pop in a catch crop of something fast-maturing, and that idea is beside a list of crops by season in case you need more ideas. There are instructions on germination testing of seeds held over from the previous year, and a chart of seed longevity. Clearly one of Ira’s goals is to reduce your chances to fail and increase your chances to succeed! The perfect gardening mentor! And one who is not trying to part you from your money. Here are resources for finding used tools free or inexpensively priced ones, and the excellent advice to view garden gear in use before buying.
There is information about growing lettuce year round, starting with basic pointers that many books forget to tell you: lettuce needs light to germinate; don’t sow it too deep; store your seeds cool and dry – they won’t germinate well if they’ve got hot; make new sowings frequently; use shade in hot weather and put ice on the seedbed; sow more frequently in late summer and early fall and use cold-tolerant varieties even though it’s still hot when you are sowing, because as day length decreases, a one day delay in sowing can lead to a one week delay in harvest.
There are useful charts of days to maturity, cold-hardiness of fall crops, and when to plant for fall harvest based on your first frost date. The fall garden is too often overlooked, and yet it is a wonderful chance to grow more fresh food and some to preserve for winter that will have been harvested closer to when you want to eat it. Ira reminds us to keep picking through the summer days, to encourage plants to keep producing more. When we get to the November chapter there is a section on Winter Garden Awareness. Although we aren’t sowing new crops, we do have plenty to harvest, and removing weeds will make for a better garden next year. There will inevitably be less to harvest in February and March, so don’t waste what we have growing before the Winter Solstice. Plan for the fall garden to mature by late November. Not much growing will happen after that.
Mulch over the rows to keep crops alive, or harvest and store before the coldest weather. Virginia snow is not the beneficial blanket that northern snows can be. Ours is wet, fleeting, heavy and unreliable. We need hoops and row covers to protect plants outdoors. Our winter gardens are susceptible to drying out the crops while the ground is frozen, and drowning them when it’s waterlogged.
After the month-by-month section is a multi-page chart of planting and harvesting. Three pages for zone 6 and three for zones 7 & 8. These are followed by an alphabetical crop section. Globe artichokes in Virginia – Ira has grown them as an annual, as other famous southern gardeners have done. Five blueberry bushes will feed four people – information like this is priceless, because you need to know before you plant and it will be a few years later that you discover the answer by yourself. Ira is part of Acorn Community, who run Southern Exposure Seed Exchange, a company selling open pollinated seed suited to the southeast. And she is broad-minded enough to recommend some quick-maturing broccoli hybrids “since timing is everything with spring plantings”, alongside OP varieties for fall. I appreciated the advice on garlic varieties, because I only know well the two varieties we grow, and people often ask me for recommendations. Nootka Rose for a long-storing softneck, Asian Tempest for early maturity, Music and Killarney Red for large cloves and easy peeling. The page on Muscadine (scuppernong) grapes is very useful to transplanted gardeners with no experience of them. Jerusalem artichokes are another crop you might not have considered. Easy, reliable, with you for life (self-propagating), they could be part of every self-reliant garden. Parsnips are another under-appreciated vegetable, “an old staple worth rediscovering”, very cold-tolerant and tasty. And there are crop-saving tips such as not to plant out peppers until the dogwood blossoms have fallen. In other words, don’t stunt them by planting out while we still have cold weather. A lesson I still need to learn.
This is a very accessible book, user-friendly, a great gift for yourself or other Virginia gardeners.
I have a few gripes with the publisher. Why get books printed in China rather than North America? Why not use recycled paper? I like the artistic background line drawings of plants (mostly a repeated artichoke head) lightly peppered throughout. The green spot-color drawings are OK to give a “quaint” feel to the book, but they often don’t match well with what Ira is saying. Ira is my neighbor and I know her favorite garden tools don’t look like these drawings!
Why not let authors provide more of the photos, so they are a better match for the text? I’ve given up trying to grow runner beans in summer in Virginia, because they don’t set pods when it is hot, (much as I love them – as a Brit, I was raised on them). There’s a photo of a (non-Virginian?) dog guarding a July harvest that I feel skeptical about. Early in the book, there is mention of runner beans as a challenging cool weather crop. The Plant and Harvest chart has them as planted in either Feb/Mar for Apr/May harvest, or July/early Aug planting for September and October harvest.
There’s a photo of kale and rainbow chard leaves, captioned as “rainbow kale.” If authors supplied the photos we wouldn’t get mix ups like this! Eye candy photos are attractive, yes, but I think people buying a gardening book will want clear accurate info above all else. I’m happy Ira got some photos of black and brown people gardening included. Most of the photos have no people, but other humans do help us relate to what we’re doing and why.
Sow summer cover crops while it’s still too early sow your winter cover crops. Sow oats 5-8 weeks before your average first frost to get good size plants before they get winter-killed. Sow winter rye from 14 days before to 28 days after first fall frost. Oats, barley, wheat and rye sown too early can head up and seed before you get to winter, making them less useful. Instead, sow fast-growing summer cover crops in any space possible, for weed suppression and a boost to soil organic matter.
Keep live roots in the ground as much of the time as possible, to feed the microorganisms and anchor the soil, preventing erosion in heavy rains. Dead roots also have a role, providing drainage channels in the soil and letting air in deeper. Adding organic matter to the soil is a way of banking carbon, as well as providing nutrients for your crops.
Deep-rooted cover crops draw up nutrients, bringing them up where crop plants can access them. Leguminous cover crops provide nitrogen, saving imports of organic fertilizers or a big compost-making operation.
Advantages of Summer Cover Crops
Suppressing weeds. Weeds grow fast in summer, and fast-growing summer cover crops will suppress them. Sowing cover crops helps us stay on top of developing problems.
Growing biomass. Many summer cover crops can be mowed or scythed down (before flowering) to encourage regrowth. The cut biomass can be left in place, or raked out and used as mulch in another part of the garden. Some can even be used as feed or bedding for small livestock.
Feed the soil life. Cover crops are solar-power generators, transforming sunlight, water and carbon dioxide into leaves and roots. They also release carbohydrates and other nutrients that feed soil microbes, earthworms and other soil life forms that make soil fertile. This cycle of nutrients constantly passes through plants and back into the soil. When you aren’t growing vegetable crops, cover crops keep this cycle going.
Increasing biodiversity. Cover crops can attract beneficial insects, birds and amphibians to feed and reproduce. Biodiversity encourages ecological balance that can help reduce plant diseases and pest attacks.
No-Till summer cover crops. A mix of soybeans or southern peas and foxtail millet can be grown during the summer and mow-killed before planting in the fall. Garlic perhaps?
Overcoming the Challenges of Summer Cover Crops
Finding space. If you’ve been carefully filling every space with vegetables, you may think you have no room for cover crops, but because they feed the soil, it’s worth making space for them too. It’s part of the wholistic picture of sustainable food production. It’s worth making a priority to have one bed or one section of your garden in cover crops, because of what they can do for your soil.
Have a goal of No Bare Soil. Seek out odd spaces to fill with cover crops.
Use space beside rows of sprawly crops short-term. Undersow buckwheat in winter squash, watermelon or sweet potatoes, and mow or till as soon as the vines start to run.
Take a cold hard look at aging crops: better than keeping an old row of beans to pick every last bean, is to pull up those beans and sow a quick cover crop. It will be a more valuable use of the space.
Take a look at your planting plan. When is your next crop going in that space? Rather than till the soil to death to manage the weeds, use a cover crop. In the winter, see if you can re-arrange your crop rotation and planting plan to make more time windows of a month or more, with the plan of using more cover crops.
Undersow growing crops with a cover crop when the vegetable crop has been in the ground for about a month. The food crop will be big enough to resist competition from the cover crop, and the cover crop will still get enough light to grow. This way fewer weeds grow, and your cover crop is already in place when the food crop is finished, giving it longer to reach a good size. We undersow our sweet corn with soybeans (soy and oats for the last sweet corn planting). Buckwheat can be under-sown in a spring vegetable crop, to take over after the food crop is finished. You can plant a short cover crop on the sides of a bed of any tall crop like tomatoes or pole beans. You will need to provide extra water, especially while the cover crop is germinating. Read my Mother Earth News post on undersowing in late summer and early fall.
You can also undersow winter cover crops during late summer and early fall to last over the winter and even the next year. We broadcast clover among our fall broccoli and cabbage with the plan of keeping it growing for the whole of the following year, mowing once a month to stop annual weeds seeding.
High temperatures. Most summer cover crop seeds will germinate just fine at high temperatures provided they get enough water.
Drought. If it doesn’t rain much in your summers, or your irrigation water is limited, choose cover crops that are drought-tolerant once germinated. After sowing, work the seed into the soil and roll or tamp the soil so that the seed is in good contact with the soil, which will help it get the water it needs rather than drying out in an air pocket. To get good germination, keep the soil surface visibly damp. You can use shadecloth, a light open straw or hay mulch, or even cardboard to reduce evaporation. Be sure to check every day and remove the cardboard as soon as you see the first seedlings.
Sowing small spaces. You can sow cover crops in rows by hand in very small spaces, or use an EarthWay seeder. Or you can broadcast: tuck a small bucket of seeds in one arm, take a handful of seeds and throw them up in front of yourself in a fanning movement, trying not to spread seed into neighboring beds where you don’t want them. Aim for about two seeds/sq in (1 sq inch is 6.5 sq cm, I’ll leave you to think what it looks like). Don’t sweat the details, you will get better with practice! This isn’t brain surgery! For more even coverage, try broadcasting half the seed walking up and down the length of the patch, then sow the other half while walking at 90 degrees to your original direction. Rake or till the seeds in, trying to cover most of the seeds with 0.5-1” (1-2.5 cm) of soil. Water with a hose wand or sprinkler to keep the soil damp until germination.
Working with the time you have left.
If you have only 28 days until the patch is needed for a food crop, you can grow mustard or buckwheat. Or weeds, if you’re careful not to let them seed!
If you have at least 45 days, you can grow soy or Japanese millet.
If you have only 40-60 days before frost you can sow oats with soy beans or spring peas as a winter cover crop to winter-kill.
If you have 50–60 days until frost, or between crops, Browntop millet is possible. In the right climate, sunn hemp can mature in 60 days.
With 60–80 days until frost, or between one crop and the next, you could sow buckwheat, soy, southern peas, spring peas, German foxtail millet, pearl millet, Japanese millet, or sorghum-sudangrass to frost-kill. Or you could sow oats with Austrian winter peas, crimson clover, or red clover to grow into winter.
If you have longer than 80 days you can sow any of the warm weather cover crops now and then move on to winter cover crops 40 days before your frost. Or you could sow a fast-growing vegetable crop.
Five Easy Summer Cover Crops that Die with the Frost
Buckwheat is the fastest and easiest cover crop, a 2’-3’ (60-90 cm) tall broadleaf annual that can be flowering within three weeks in very warm weather, 4 weeks in regular warm weather. Because it grows so fast, it quickly crowds out germinating weeds. Plant buckwheat after all spring frosts have passed, until 35 days before the fall frost at the latest.
If you have longer than 4 weeks for cover crops, you have the option of letting the buckwheat self-seed and regrow (only do this if you’ve finished growing vegetables for that year in that space). Another option if you are not close to the frost date is to incorporate the buckwheat in the soil and then sow fresh seed.
Buckwheat is very easy to incorporate into the soil. Use a mower or scythe to cut it down 7-10 days after it starts flowering, and then either let the dead plants die into a surface mulch and plant into that, or rake it up and compost it, or dig or till it into the soil. For small areas, you can simply pull up buckwheat by hand – this is what we do in our hoophouse.
Buckwheat can be used as a nurse crop for fall-planted, cold-tolerant crops, which can be difficult to germinate in hot weather. Sow a combination of buckwheat and a winter vegetable to shade and cool the soil. When frost kills the buckwheat, the vegetable crop can continue growing with no competition.
Buckwheat is not related to any of the common food crops, and so it is simple to include it in crop rotations.
One of our favorite summer cover crops is sorghum-sudangrass, a hybrid that grow 5’-12’ (1.5-3.6 m) tall in 60-70 days and produces an impressive amount of biomass. You’ll need big machinery, at least a big BCS mower, to deal with sorghum-sudangrass. If you have only hand tools and a lawnmower, I recommend growing German foxtail or Japanese millet instead.
Plant sorghum-sudangrass about two weeks after your first sweet corn planting date and anytime onward until six weeks before frost. After it’s established, sorghum-sudangrass is highly drought-resistant and thrives in summer heat. Plant in rows 8” (20 cm) apart, with seeds 1’ (2.5 cm) deep, 1.5” (4 cm) apart. Sorghum-sudangrass will smother weed competition, and make big improvements to the soil texture and the levels of organic matter.
When the sorghum-sudangrass reaches 4’ (1.2 m) tall, cut it down to 1’ (30 cm) to encourage regrowth and more, deeper, roots growth that will loosen compacted soil. The cut tops make a good mulch, or you can leave them in place.
Sorghum-sudangrass roots exude allelopathic compounds that suppress damaging nematodes and inhibit small seeds (weeds and crops) from germinating and inhibits the growth of tomatoes, lettuce, and broccoli. Wait at least 6 weeks after killing sorghum-sudangrass before planting another crop in the same spot. Plant earlier at your own risk – I think we’ve had some success despite the warnings. Be careful if feeding to livestock. Read up about prussic acid poisoning from this cover crop.
These are a quick easy leguminous cover crop for warm weather. Buy organic seed if you don’t want GMOs, as almost all non-Organic soybeans in the US are GMOs. We plant these whenever we have a minimum of six weeks for them to grow before frost or before we’ll need to turn them under. They aren’t the highest N-producing legume, but they are very fast-growing and easy to manage.
Also known as cowpeas, although I have heard this might be perceived as insulting by African-American families who use them as food. Southern peas grow fast (60-90 days), thrive in heat, and are very drought-tolerant. Their taproots can reach almost 8’ (2.4 m) deep. They grow well in almost any soil, except highly alkaline ones. Southern peas attract beneficial insects.
Sow southern peas 1-2 weeks after your sweet corn, when the soil has warmed up. You can continue sowing until 9 weeks before a killing fall frost. Sow seeds 2” (5 cm) apart, 1” (2.5 cm) deep in rows 6” (15 cm) apart (give vining types more like 15” (40 cm) between rows. Close planting is needed to shade out weeds.
Because they are fast-growing, southern peas can follow spring vegetable crops and fix nitrogen in time to feed heavy-feeding, fall-planted onions or garlic.
Sunn hemp is a nitrogen-fixing legume from the tropics, which can grow as much as 9’ (2 m) tall in just weeks. Sow sunn hemp from 1-2 weeks after your sweet corn sowing date, up to 9 weeks before a killing frost. It tolerates a wide range of soils (but not if waterlogged), and dies with the frost. Plant inoculated seed (use the same inoculant as for southern peas) 1” (2.5 cm) deep, with seeds 1.5” (4 cm) apart in the row, and with rows 6” (15 cm) apart. Sowing densely will smother the weeds.
If you sow in a summer gap between spring and fall vegetable crops, it will provide a nitrogen boost for the fall crop. In dense plantings, it can fix more than 120 lbs (54 kg) of nitrogen and 12 pounds of biomass per 100 sq ft (0.56 kg/sq m). 60 days after sowing, the stems thicken and become fibrous and high in cellulose; cutting at this stage produces long-lasting mulches that increase soil carbon. If you cut the crop back at a younger stage, this will stimulate branching (more biomass) and more root penetration (better drainage).
Late Summer Cover Crops for Winter: Oats and Barley
In late summer you can sow oats for a winter cover crop that will be killed at 6°F (-14°C). We sow in late August and early September in Zone 7. Inexpensive and easy to grow, oats are a standard fall cover crop: a quick-growing, non-spreading grass, oats will reliably die in Hardiness Zone 6 and colder, and nine years out of ten in zone 7.
Barley grows even faster than oats, and on average it will get killed later in the winter. It usually dies at 17°F (-8°C), making barley another choice for gardeners in regions where oats are used.
Cover Crop Resources
My book Sustainable Market Farming has a chapter on cover crops and 9 pages of charts about particular options.
The book Managing Cover Crops Profitably (third edition) from the Sustainable Agriculture Research & Education Program (SARE), is the best book I know on the subject. You buy the book for $19 or download it as a free PDF from SARE.
PART SIX: Planning to grow potatoes again (September)
I have a whole chapter about potatoes in Sustainable Market Farming, where most of this information can be found.
See Root Crops in June for info on digging up new potatoes, if you can’t wait for them to mature! Harvest for immediate use anytime you’d like after the tubers reach a big enough size.
Preparing for potato harvest
When the leaves start to turn pale, the plant has finished its leaf-growing stage and will be putting energy into sizing up the tubers under the ground. Avoid irrigating at the end of the growing period or the potatoes may develop hollow heart, make knobby secondary growths or even crack. For maximum yield, and to harvest for storage, wait until the tops are completely dead.
In England, we planted in spring and harvested in October, waiting for the frost to kill the vines. In Virginia, we plant in March and June, harvesting in July and October. For our unmulched March-planted July harvest, we mow two weeks before our planned harvest, to fit a tight crop turnaround. In hot weather the cut tops and weeds dry up. If more weeds grow, we mow again the day before harvest. For our fall-harvested crop, planted and mulched in June, we need to remove the mulch after the mowing and before the harvest. This is a slow job, but necessary, and the mulch makes a good addition to our compost pile. If it looks like rains will delay the harvest, or nights are forecast to be very frosty, we delay de-mulching until the day before harvest.
Varieties such as Red Pontiac, Yukon Gold and Kennebec are determinate — they grow as a bush, then flower and die. If you have indeterminate varieties such as Russet Nugget, Nicola, German Butterball or Elba, you will need to kill the vines. I’ll come back to the topic of determinate and indeterminate varieties in Part Six, Planning to grow potatoes again (September). You can bring about an early vine death by mowing or flaming. This will also remove weed growth that could interfere with your digging equipment.
Whether the vines die naturally at the end of their lifespan, or they die of disease, or the frost kills them, or you do it yourself by mowing or flaming, it helps storability to wait 2-3 weeks more before harvesting to allow the skins to toughen up. They become more resistant to scrapes and bruises) and the potatoes become higher in dry matter. Harvesting is also easier if the vines are well dead. Test by digging up a sample and rubbing the skins. When the skins don’t break, the potatoes are storable.
Be sure to have enough crates, buckets, totes, gloves and workers. Clean and air the root cellar and warm it to 70°F (21°C).
Harvesting your potatoes
If possible, harvest when the soil moisture is 60-80% of field capacity. Not too dry, not too wet. This reduces damage from scraping. Ideally the soil temperature will be 45°-65°F (7°-18°C). Because soil temperature lags 3-4 hours behind air temperature rise each day, in cold weather, try to harvest late in the day, but with time to finish before dark. In hot weather, harvest in the morning as early as possible. Tuber temperature will also affect bruise and rot susceptibility. Do not harvest when tuber temperatures are below 45°F (7°C) or above 85°F (30°C).
We use a Checchi and Magli single-row side delivery SP100 harvester. It does a good job in clean soil and an excellent job in clean fairly dry soil but gets stuck if we have a lot of organic material on the soil (weeds or mulch). The 1-row Potato Digger from US Small Farm Equipment, which a neighboring farm bought, has the same challenge. If using a digger, don’t set it too deep, or too much soil will be dumped on the harvested potatoes.
During harvest, someone walks alongside the tractor with a long-handled hook/claw tool, to clear blockages and hook any potatoes from the path of the tractor wheels. The rest of the crew follows, picking up and sorting the potatoes. If they are wet, we leave them to dry for a short time. We sort the damaged ones into “Farm Use” buckets and crate up the good ones. We try not to leave any potato parts in the field, to reduce the chance of spreading diseases.
When freshly harvested, potatoes are tender, breathing things. Avoid bruising, which is damage that does not break the skin, by not dropping potatoes more than 6” (15 cm), or throwing them towards a container. Don’t bang them to knock off extra soil. In hot weather we aim to work until done and not leave any potatoes in the field baking for long. In cold weather we aim to get done before nightfall and not have any freeze overnight!
When harvesting in summer, we stack the crates of potatoes covered with a tarp, under a big tree overnight to lose some of the field heat before moving them to the root cellar early next morning. For the fall harvest, if the weather is chilly, we take the crates straight into the root cellar. Potatoes you take from storage can be no better than the quality of the potatoes you put into storage!
Potato harvesting raises rocks to the surface, so we try to find time soon after the potato harvest to collect them for use in road repairs and construction.
Yields are likely to be 150 lbs/100ft (223 kg/100m); 200 lbs/100 ft (300 kg/100m) or more is a good yield; double this is possible. In my book Sustainable Market Farming, in the potato chapter, I made a mistake and gave these as pounds per acre, which would be a miserable yield! 5 gallon buckets and square plastic “milk” crates hold about 30 lbs each (14 kg)
Post-harvest two week curing
After harvest, potatoes need to cure for two weeks at a surprisingly warm temperature: 60°F–75°F (15.5°C–24°C), and 95% humidity. While curing, the root cellar will need 6-9 hours of ventilation every two or three days. The potatoes are still actively respiring, so they need a good oxygen supply. Failure to ventilate enough can lead to Blackheart, where the inner tissue of the potatoes dies and turns black.
Potatoes will heat up if left closed in. Ventilate when the temperature is 0-20 F° (0-11 C°) cooler than your goal: air in the daytime if nights are too cold and days are mild; at night if nights are mild and days too warm. Try hard to avoid having the cellar cool down, then warm up. That causes the potatoes to sprout. If there is too much condensation, use a fan and open the cellar doors, when temperatures are closest to the goal. During the curing period, the skins toughen up more, and cut surfaces and superficial wounds heal over, enabling long-term storage.
Sorting and preparing for long-term storage
After two weeks, we sort through the whole storage crop for rot, We find that this single thorough sorting can remove almost all of the storage problems that are going to happen. Not sorting at this point lets rots spread.
After the curing period, the potatoes become more dormant and do not respire so actively. Fresh air is needed about once a week in weeks 2-4, after which air exchange is not needed. Relative humidity should be 90-95%, to keep weight loss to a minimum, but not 100%! If the cellar is too warm, you will need to ventilate to lower the temperature.
Once potatoes are more than a month from harvest, the temperature, should be 40°-50°F (4.4°-10°C), and closer to the lower end of the range is best for long-term storage. In summer we work hard to reduce the temperature to 50°F (10°C) for long-term storage, but in the winter we can reach 40°F (4.5°C). Constant temperatures or a steady decline is the goal, not dramatic fluctuations, as these can cause stress and physiological aging, which leads to sprouting. Hotter temperatures promote more rot, and age the potatoes faster, also leading to early sprouting.
Potatoes have a natural dormancy of 60-130 days (depending on the storage temperature). After that period, they will start to sprout.
I will address long-term storage and preventing sprouting in Part 5 next month.
July is not a good month for sowing many root crops in Virginia – it’s hot and for most fall root crops we can do better waiting till August. Yes, it will still be hot in August, but the daylight is getting shorter and so the hot part of the day is also getting shorter.
Carrots: if we really need more carrots, we direct sow our eighth bed of carrots in early July. We only do this if they’re really needed, because carrots grown in hot weather do not have the best flavor. They will not be sweet, they may even be bitter.Our plan is to have grown enough between February and May to last us until late October, stored in perforated plastic bags in the walk-in cooler. But if earlier sowings weren’t all successful, or we ate unusually large amounts of carrots, we can find ourselves sowing them in July.
Use shadecloth to keep the soil damp, or water a lot. Carrot seed will germinate whenever the soil is below 95°F (35°C), provided you can keep the soil damp until the seedlings emerge. You won’t need to do daily watering for long: maybe only 4 days. We flame summer carrots on day 4 after sowing, because we have found that carrots can emerge on day 5 in summer temperatures, despite longer times given in the charts. See Root Crops in May for more about sowing and growing carrots, including pre-emergence flame weeding.
Kohlrabi:Kohlrabi transplants successfully, unlike carrots and turnips, and this has usually been our method for fall crops. We have sown kohlrabi (Early Purple Vienna and Early White Vienna) in the week beginning July 2, for transplanting 8/3-8/9. Sowing in early August is also possible, for November harvests. Kohlrabi, like other brassicas, can be grown in spring or fall in our zone 7 climate. It’s not actually a root crop, rather a swollen stem, but I’m including it as an “acting root”
Rutabagas: This year we are growing rutabagas (also known as Swedes) again, after several years when we went with more turnips instead. Rutabagas are only sown here in late summer for winter storage. They take longer to grow to a good size than turnips do, so it is necessary to start earlier: 7/15-8/4 here, (mid-August at the latest), allowing 90-100 growing days before a hard freeze.Fall root crops sown too early in the summer can get woody. See the Special Topic for July below for all the details about rutabagas.
Root Crops to Harvest in Central Virginia in July
Potatoes: From mid-June onwards, we can harvest spring-planted potatoes as delicious “new” potatoes. See Root Crops in June for more on this. For maximum yields, hold off on harvesting until two weeks after tops have died. See next week’s post for all the details.
Beets: We like to clear all our spring beets by the end of June, but sometimes the job flows over into July. Trimmed beets keep well in perforated plastic bags under refrigeration. Store beets at 32°F (0°C) and 95% humidity.
Carrots: Our third carrots (sown mid-March) should be cleared in early July if not before, and our fourth carrots (sown in late March) and fifth (sown in mid-April) will also be ready to harvest in July. I usually reckon on three months from sowing to harvest for carrots, but they can be faster in warm weather. Don’t leave them in the ground too long, or they will get woody. See Root Crops in June for more on carrots.
Kohlrabi: As with beets, we plan to harvest spring kohlrabi by the end of June, at 3” (7.5 cm) in diameter (or even up to softball size). They get too fibrous if left longer, so we will prioritize getting them up. The base of the globe can be tough, so cut either the wiry root just below the soil surface, or cut higher, leaving a small disc of the globe behind, attached to the taproot.
Turnips:If we didn’t finish harvesting our spring turnips by the end of June, we really need to get them all up in early July. If we have more than we can eat in the next week, we store them in perforated plastic bags in the walk-in cooler, eating them during the summer. Turnips keep for about 4 months at temperatures close to freezing and humidity of 90-95%. Higher humidity will make them rot (rotting turnips are pretty unpleasant!)
Other Root Crop Tasksin Central Virginia in July:
After all the spring-sown root crops are harvested, and the spring-sown greens have bolted, we prepare the emptied beds for summer or fall crops.
Preparing space for summer-planted crops
In July, we will be looking for beds to plant successions of lettuce, cucumbers, squash and beans; our fall brassica transplants, and our first transplants of fall and winter cabbage and Asian greens. In August, we’ll want beds for our last plantings of cucumbers, squash and beans, the never-ending lettuces, fall beets, turnips, winter radishes, kale, and collards. Harvesting the spring roots promptly and storing them gives us time to prepare the beds for their next crop.
If we have 4 weeks or more before the next crop, we will sow a cover crop of buckwheat in the just-emptied beds. Buckwheat keeps the weeds down and feeds the soil (and the honeybees and other pollinating insects). If there are weeds or lots of crop debris, we will till deep enough to bury that plant matter, then broadcast the buckwheat at a rate of 2–4 oz/100 ft2 (6–12 gm/m2), give another shallow tilling, then water and stand back. If there are no weeds or crop debris, there’s no need to till: you can broadcast the seed, and rake it in before watering (and standing back!). As an alternative to broadcasting you can sow rows of buckwheat with the #22 plate on an EarthWay seeder.
Prepare stale seed beds for fall carrots
If you have less than four weeks before you need to sow or transplant the next crop, you can use the time to kill weeds with the stale seedbed technique. Prepare the bed as if you were about to sow, producing an even surface with a fine tilth (surface texture). Then water as if you had sown something, keeping the surface damp by watering as needed. As soon as you see tiny weeds germinating, hoe the surface very shallowly in sunny breezy weather and let the weeds dry out. Make a last hoeing the day before sowing the next crop. This is especially useful for carrots, scallions or anything with tiny seedlings, which cannot easily compete with weeds.
Another method of germinating and killing weed seedlings when there is no crop in the ground is tarping: cover the bed with an opaque waterproof cover after watering the soil. Weeds seeds germinate, but the weeds cannot grow without light and will die.
Solarizing is another approach that works well in hot weather: cover the prepared bed with clear agricultural plastic, such as scraps of a hoophouse covering. The heat of the sun bakes any weed seeds near the surface, and also any disease spores or small pests. Larger creatures such as earthworms can burrow deeper into the soil (as they do anyway in hot weather).
Special Root Crop Topic for July in Central Virginia: Rutabagas
Rutabagas need to be sown in July in central Virginia. To clarify: rutabagas (known as Swedes in the UK) are Brassica napus, closely related to most other brassica crops. Botanically, rutabagas are part swollen tap roots, part swollen stem (the upper portion of the vegetable which forms the neck, the distinguishing feature of rutabagas). There are secondary roots growing in two rows down the sides of rutabagas. Rutabagas are mostly yellow-fleshed with a tan and reddish or purplish skin, although there are white-fleshed varieties. They all have blue-green waxy, non-hairy leaves. turnips are Brassica rapa, like Chinese cabbage and mustards. Turnips come in a range of colors, white or yellow flesh, with white, purple, red or golden yellow skins. The leaves are bright grass green, usually hairy, and not waxy. Turnips do not have a neck or secondary roots growing off the turnip. Rutabagas have twice the nutrients of turnips. And take longer to grow.
Rutabagas are among the hardiest of vegetables, and can be left growing (or at least not dying) until all other crops have been harvested. The flavor improves after frost. For small plantings, plan on 10’ (3 m) per person. Yields of rutabagas can be 75-180 lbs of roots/100’, (35-80 kg roots/30 m): 50% higher than turnips.
Rutabagas come in very few varieties. Laurentian (95 days OP) has a deep purple crown and cream yellow bottom. The uniform 5–6″ (13-15 cm) roots have sweet pale yellow flesh. Joan(90 days, OP), looks similar to Laurentian, with the added advantage that itis somewhat tolerant to club root. Gilfeather(85 days, OP) is sold as a turnip, but is botanically a white rutabaga. Sweeter and later to mature than turnips, it doesn’t become woody even at softball size. Southern Exposure Seed Exchange also hasAmerican Purple Top(not to be confused with the Purple Top White Globe turnip) and the Lithuanian Nadmorskaa large oval 90d OP.
Keys to growing mild, sweet-tasting rutabagas include cool temperatures, sufficient irrigation, and no competition from weeds or over-crowding. The optimal germination range is 59-95°F (15-35°C). Rutabagas are a little slower to germinate. We sow four rows in 4’ (1.2 m) wide beds. Seeds need to be 0.5” (1.2 cm) deep. When flea beetles or grasshoppers are a problem, use rowcover or insect mesh.
Early thinning is especially important for shapely well-developed rutabagas. Thin to 4” (10 cm) within 10 days of emergence, or at least by 1” (2.5 cm) tall, then to 10” (25 cm) when 2-3” (5-7.5 cm) tall. If not well-thinned, they will grow in odd shapes and be small.
Boron deficiency causes the middles of the roots to turn brown. Many common weeds are in the Brassica family, and could harbor pests and diseases that could attack the crop, so use crop rotations, stale seedbeds and clean cultivation to remove the weeds.
Aphids, flea beetles, cabbage worms, harlequin bugs, and grasshoppers can all be a problem. Rutabagas have worse trouble with aphids than turnips. Brassica flea beetles are not the same species as the nightshade flea beetles often found on eggplant. Rowcovers or insect netting and the planting of insectaries (flowers to attract beneficial insects such as ladybugs) can help avoid the problems. Bt can be used for the caterpillars, soaps for the aphids and Nolo bait for the grasshoppers (except where banned in order to preserve rare species of grasshopper).
The main diseases of rutabagas (and turnips) are club-root, downy mildew, powdery mildew, rhizoctonia rot, bacterial scab, and blackleg. All except scab are fungal diseases. Organic methods of prevention are crop rotations and field sanitation (plowing in residues promptly, removing weeds). Club-root fungus is able to live in the soil for up to 10 years, so is hard to eliminate. Avoid all brassica crops in an affected field for 10 years, and be vigilant about eliminating brassica family weeds. (Develop a fondness for spinach, chard and beet greens!)
Our rutabagas are ready from mid-October. Rutabagas (but not turnips except in warm climates) can be stored in the ground all winter. Mulch over them with loose straw once the temperatures descend near 20°F (-7°C). If you don’t manage to eat all the roots before spring, they will re-sprout and you can have an “early spring bite” of greens (a term more usually used for cattle fodder crops).
Rutabagas can store for as much as 6 months in perforated plastic bags under refrigeration. They do best stored above 95% humidity. Prompt washing before the soil dries on the roots will make them easier to clean later.
In the UK, rutabagas are not waxed as they are in North America. In fact, they store well without waxing, and I encourage you to try skipping the petroleum product.
In May I gave information on planting sweet potatoes. Hopefully that went well for you, and by now you have a large patch of healthy green vines. Let’s keep it that way! Here I will tell you about what the growing plants need, and the pests, disease and afflictions to avoid.
This paragraph was included in Planting Sweet Potatoes, and I’m repeating it here, as a good reality check on what you can expect.
Regardless of how early in the season you plant them out, they will not make flowers earlier, or start making tubers sooner. Both flower and tuber initiation are triggered by day length. Each variety has its own internal clock. Most varieties take 90–110 days from planting out to reach a good size, if the weather is warm enough.
The first month or so after transplanting is the root development stage. Roots can go 8’ (2.4 m) deep in 40 days. Don’t be alarmed at the lack of above-ground action. The second month or so is the vine growth stage. The roots begin to store starch and sugar close to the stem base. During the last month of growth for that variety (3rd or 4th month), the potatoes develop. Make sure you dig them up before the soil temperature gets down to 55˚F (13˚C) – the week of the average first fall frost is about right.
Growing sweet potatoes – Three Ws: water, warmth, weed-free
The critical time to maintain sufficient moisture is after transplanting for at least the first 20-40 days while roots are developing. By now, most growers will be beyond this most-important watering period. But if it’s less than 40 days since you planted them out, keep the soil moist. Use your fingers to test the soil for dampness.
Once they are established, sweet potato plants are fairly drought-tolerant. But if you want high yields, they’ll need water once a week, either from the sky, or provided by you. Note that if you are using plastic mulch, rain won’t go through it, so I hope you installed drip irrigation below the plastic. If not, lay it on top, right beside the plants. Aim to provide an inch (2.5 cm) of water per week.
Sweet potatoes need warmth! Heat determines success; the number of days from planting does not.
Provided the weather is warm enough, most varieties take 90–110 days from planting out to reach a good size.
You can gain warmth in a cold climate, by planting inside a hoophouse or low tunnel covered in clear plastic. Ventilate in hot weather.
Growing Degree Days (heat units) are a tool for measuring accumulated heat, but you don’t need to calculate GDDs to get a good crop!
Early varieties take 1200 GDDs to grow a good crop.
To calculate GDDs, take the day’s high temperature (max) and the day’s low temperature (min) and add them together. Divide by 2 and subtract the base temperature of 55F. (Apologies to the rest of the world – I only know this method using Fahrenheit, but I’m sure you can find out how to do the calculations in Celsius). There are phone apps that will do the calculation for you.
Example: For a daytime max of 90F, and a night-time min of 70F, you get 25 GDDs – just about perfect for sweet potatoes. 90+70=160. 160/2=80. 80-55=25. At 25 GDDs a day, you theoretically only need about 48 days to get a crop. There are some other limits to daily plant growth – the likely minimum for a decent crop is about 76 days.
In a plastic tunnel, you can get 20 GDDs a day or more, rather than the 5 you might get outdoors.
Cultivate to remove weeds until the vines cover the ground, after which very little weeding will be needed.
If you have plastic mulch, walk through pulling weeds, and drop them on the plastic to cook. If you are growing on bare soil, hoe while the weeds are small, and pull if the weeds and the vines get ahead of you.
Weeding is generally not onerous because the sweet potato vines cover the ground within 6 weeks of planting and smother any newly emerging weeds.
Deer eat sweet potato plants at all stages, including digging out the roots in the fall. Dogs, fences and guns are the three most effective methods of deer control. The plants can be covered with row cover or plastic net for the growing season. Motion-sensor sprayers work well if maintained.
Rabbits eat the foliage. Plant the slips on black plastic to hold back weeds, then put wire hoops over the rows and cover with row cover for 3–4 weeks while the plants are young. Even after the plants are large rabbits can cause substantial losses.
Groundhogs dig and eat the roots. They can be trapped with baits of fruit. What’s for dinner?
Pocket Gophers search out sweet potatoes to eat. Their mounds may be hidden under the foliage and the plants may survive as they only eat the larger roots, leaving no crop.
Voles move in from grassy areas to live under the mulch and feed as fast as the roots form. They eat the roots from the top down leaving the outer shell in the soil where they have feasted. Cats are the best control.
Rats love the roots. Cats or dogs are the best methods of control.
Field Mice build nests under black plastic and eat the roots emerging from the ground.
Human “pests” of sweet potatoes
You can eat sweet potato leaves yourself and it takes several meals to reduce yields of the tubers. Some researchers working in Vietnam, discovered that harvesting 25%, 50%, 75% or 100% of the vines every 15, 20, or 30 days (ignoring the information about the season of the year and the varieties) gave the sort of results you might expect. Harvesting tops every 20 days gave highest yields of greens. Harvesting 50% of the greens each time gave highest total yields of greens. Harvesting not more than 25% or 50% of the greens each time gave the highest eventual tuber yields, after 120 days. Researchers in Tanzania came up with the clear information that harvesting three times at one month intervals gave the highest greens production, but the tuber yield was affected tremendously. Harvesting tops twice in a growing period proved the best in leaf production as well as root yields. So, clip 25-50% of the tops of each plant up to twice in one summer, and you’ll still get a good yield of roots.
Although there are many insect pests that feed on sweet potato vines and leaves, most do very little damage, and hunting them down is not justified.
Pests that feed on foliage
Sweet potato flea beetles – Tiny black/bronze oval beetles (1.6 mm long), with reddish-yellow legs, and ridged wing covers; make small shot-holes in leaves or grooves in the upper surface of the leaves. Damaged areas turn brown and die. See below about larvae.
Sweet potato weevil adults and larvae do feed on the foliage, but mostly go for the roots (see below).
Caterpillars of three kinds:
Southern armyworms – Gray-black larvae up to 36 mm long with green or pink tints; pale longitudinal stripes and pairs of triangular spots along the back; pale yellow heads with bright red-brown marks. They feed on leaves and tips of vines, and congregate around the bases of plants during the middle of the day.
Sweet potato hornworms – First instar: white with a black horn; later instars (up to 90 mm long): green or brown with black diagonal lines down each side and a black horn, with a green or brown head with black stripes. They defoliate plants and often hide under leaves near the bases of plants.
Yellow-striped armyworms – Pale gray-black caterpillars up to 45 mm long, with orange-yellow stripes along the sides and pairs of triangular spots on the back of most segments; brown heads with black markings and a white inverted V. They feed similarly to southern armyworms.
Potato leafhoppers – Wedge-shaped insects up to 3 mm long; green bodies with yellow to dark green spots. They usually jump rather than fly. They suck sap from the underside of leaves causing yellowing of leaf tips and margins.
Fruit or vinegar flies – Small yellowish red-eyed flies about 3 mm long. They hover around overripe or decaying produce. They may be found with their small creamy maggots in cracks in sweet potatoes.
Tortoise beetle adults and larvae – Long-oval shaped gold beetles, up to 8 mm long, with various black or red markings on their flattened, shell-like bodies. The larvae have dull yellow, brown, or green bodies up to 12 mm long and black heads, legs, spots, and spines. Long spines on the abdomen hold excrement. Adults and larvae chew the leaves riddling them with holes.
Spider mites – Tiny reddish or pale spider-like arthropods that feed on the underside of leaves. Heavily infested plants develop a yellowish, bronzed or burned appearance.
Pests that feed underground on tubers and side roots
Sweet potato flea beetle larvae – Thin white, cylindrical larvae, up to 5 mm long, with 3 pairs of legs near their heads. They make shallow, winding tunnels on the surface of sweet potato roots and sweet potatoes. The tunnels darken, split, and leave scars.
Sweet potato weevil adults and larvae –Snouted beetles 6 mm long with dark-blue wing cases, orange-red legs and thorax, and fat, legless, 9 mm grubby white larvae with pale brown heads. The beetles make small holes over the surface of sweet potatoes mostly at the stem end. The larvae tunnel inside the tubers, leaving frass, which causes the sweet potatoes to taste bitter.
White grubs (spring rose beetles) – Dirty white grubs up to 25 mm long with brown heads and 3 pairs of legs near their heads. They leave large, shallow feeding scars on the sweet potatoes.
Wireworms – Thin, tough, wire-like larvae with 3 pairs of short legs near their heads and prolegs at the end of the body. They initially create large shallow cavities in sweet potatoes which they later excavate into deep ragged holes. Three species, with colors from yellowish-brown to cream or yellow-grey. Heads are darker, brownish.
White-fringed beetle larvae – Yellow-white legless, 12-segmented grubs, up to 13 mm in length, with small, pale heads. They chew into the roots.
Afflictions of sweet potatoes (these are not caused by disease organisms)
Round chunky roots, low yield, purple color: Planted too early, too cold.
Low yield: Flooded or crusted soil 6-7 weeks after planting? Planted too early?
Rough irregular shaped roots: Heavy clay soils or organic matter above 2%.
Rattails – thin, tough, tubers: Hot dry weather, insufficient water.
Brownish skin patches, worse in wet years: Scurf fungus, Monilochaetes infuscans. More likely if too much compost was used. Stored roots shrivel.
Metallic black surface lesions, maybe covering most of the root: black rot fungus, Certocystis fimbriata. Internal decay is not deep, but the fungus may impart a bitter flavor.
Sunken brown lesions that may completely encircle the root: ring rot, Pythium
Sunken lesions that dry and may fall out: Circular Spot, Sclerotium rolfsii. May taste bitter.
Hard, dry, black, sunken spots developing in harvest wounds: Fusarium. Spots may become larger than 2″ (5 cm) diameter, but damage is not deep.
Pitting: Soil rot or soil pox fungus in the presence of water stress. Roots will be small and malformed.
Streptomyces root rot bacterium causes a similar rot.
Fine or coarse irregular cracks, browning of the surface; dry, corky, dark-colored clumps of tissue scattered throughout the flesh, becoming worse if roots are stored warmer than 60°F (16°C): russet-crack/internal cork, feathery mottle virus (yellow feathery patterns of leaves). Do not use as seed stock.
When to harvest sweet potatoes
Unlike white potatoes, which have the annual plant sequence of vegetative growth, flowering and dying back, sweet potato plants would go on growing forever if the weather remained warm enough. Choose when to dig them up, ahead of cold weather. The longer you wait, the bigger the potatoes, but you are gambling with the weather. Usually sweet potatoes are harvested in the week that the first frost typically occurs in your region. I have written plenty already in previous years about harvesting, so I won’t go into it here. See one of the links to those posts, or my slideshow, if you want to know what comes next, or your climate is considerably colder than mine in central Virginia.
Book Review: No-Till Intensive Vegetable Culture, by Bryan O’Hara
Chelsea Green, 2020. 250 pages, full color photos throughout, $29.95.
Bryan O’Hara’s No-Till Intensive Vegetable Culture is the work of an expert. His bio says he is known for “providing mountains of details in a concise, practical and cohesive manner”, which sounds like my kind of writer!
His book includes science, art, and philosophy. It is an example of something I realized a while ago: if a farmer pays good attention to what works well, and acts in accordance with their observations, it doesn’t seem to me to matter exactly why they think it works! Although I don’t share the author’s spiritual outlook, or practice of Biodynamics, I do highly value healthy soil, diverse ecosystems, crop rotations, nutritious food, good relations with our neighbors and peace in the world. And so I can use the pointers to achieve some of these goals. Bryan has been paying exquisite attention for decades!
This no-till book is very different from Andrew Mefferd’s Organic No-Till Farming Revolution: High-Production Methods for Small-Scale Farmers which I reviewed in May 2019. That book provides a menu of varied methods for those who want to increase the amount of no-till growing on their small-scale farm. Any reduction in tillage is a good step: you don’t have to commit to permanent no-till everywhere. Read Andrew’s book first and choose the reduced-tillage options that suit your farm. Then read Bryan’s book on one particular way of no-till vegetable production and see which parts will work for you.
Bryan and his partner Anita started farming in Connecticut in the early 1990s. Experienced, enthusiastic and energetic, they quickly succeeded, and prepared to expand Tobacco Road Farm. Fortunately, Anita realized the three acres of vegetables they already had was a better fit with their goals: providing for their family year-round, keeping them healthy and happy, providing a service to fellow humans, and freedom from economic subjugation. They embraced Biodynamics as a way to improve crop health, and then Korean Natural Farming. KNF (developed by a Korean, Cho Han Kyu) and making brews of microorganisms (IMOs).
After noticing that tillage was detrimental to their soils, they switched to no-till and were stunned at the differences. The vegetables taste wonderful!
Bryan writes an inspirational narrative, without any fluffy chat. It’s like being in conversation with him. Not everyone can make a discussion of soil quality so engaging! He has a suitable humility about stepping in and influencing the fine balance of the ecosystem. His advice: “be careful not to get in the way of delicate, naturally functioning systems.”
I was surprised to find that Bryan believes that long-lasting condensation trails left by high-flying aircraft under certain conditions are actually “chemtrails” of chemical or biological agents secretly sprayed on us, rather than water-vapor. I do agree that airplane flights significantly add to climate chaos. We who sometimes fly have the responsibility for this, not secret government departments. Like Bryan, I lament the erratic weather, the decline in insect populations, and the struggle to provide water for our livestock and crops in appropriate quantities and rates of distribution.
Bryan describes increasing or decreasing the strength of both or just one side of the growth/reproduction polarity of plant development. Keep the balance of air and water in the soil. Steer things in the direction your crops need. Don’t let the soil dry out, as many life-forms will die, and recovery won’t be instant. But how do we get there from here? Bryan offers suggestions for what to look for when “reading” the appearance of crops in terms of balance. Rank growth? Stunted? Sparse? Obvious nutrient deficiencies? Good yield? Color?
Bryan suggests monitoring the conditions of the soil, air, sunlight and water. Whether you see this as a manifestation of Pagan Earth/Air/Fire/Water elements, or a simple description of aspects of farming doesn’t matter to me. As an example, if you want consistent supplies of an annual cool weather crop, sow several successions in spring (because they will quickly bolt) but fewer in late summer because they will not bolt. Once you understand this, you can follow the cycle of “plan/execute/observe/adjust plan” and get the best possible fit of crops with markets. Your approach may be mystical or pragmatic, but your attention to results will be detailed either way.
If you are drawn to Biodynamics, I think you’ll love this book. If you are drawn to very successful crops, I think you’ll also love this book. You just might skim some it.
The next section of the book is about preparing land for a gradual transition to no-till. Don’t expect to make an overnight change! Try various approaches on small areas. Reduce your tillage until you no longer need any, or just need occasional tillage. Don’t worry that opening a furrow for big seeds, or digging up root vegetables, will get you expelled from the No-Till School! Try to avoid tilling simply to prepare seed beds.
Various conversion methods are explained, even clearing woody growth. First set up a system that doesn’t need primary tillage (usually heavy tractor equipment), but uses secondary tillage tools (rototillers, disk harrows, field cultivators, walking tractors, hand rakes and hoes) for bed prep (and occasional subsoiling to deal with hardpan).
Bryan recommends a three step process for killing old crops or weeds. First is mowing: Bryan most often uses a flail mower on a 16 hp BCS 850. Second is preventing regrowth by solarizing using clear plastic sheeting to heat the soil surface to 125F or more, for a day. Unlike solarizing to kill pathogens deeper in the soil, killing annual crops or weeds is very quick, provided air temperatures are 75F or more. Perennial roots will not solarize quickly – it’s best to remove these before transitioning. Those that arrive later will need digging out, or longer term solarizing using black silage tarps over the winter. For anti-plastic growers, organic mulches of cardboard covered in 2 ft of fresh cut hay can substitute. There is a good review of various mulching materials, and the photos show his own trials. Oak leaves (and coffee grounds) seem to repel slugs!
Mowing or rolling and crimping is another method, given a thick cover crop and good timing. Flaming can work to kill emerging weeds if any mulch is well-watered first. Reading the book will save you trying all the cover-management methods that don’t work well. At Tobacco Road Farm, they now solarize as much as ¼ acre at a time, moving the covers from plot to plot.
The chapter on seeding and transplanting includes a chart of planting methods, seeding rates and spacing for about 65 crops (not just the top twenty!), instructions for hand broadcasting, sowing in rows by hand or by EarthWay. They have learned to get the most from their Earthway, customizing plates, leaning right while pushing, and only half-filling the hopper for round seeds (to avoid the “brassica grinder” effect).
The transplanting section describes clearly how to make use of outdoor nursery seedbeds for growing bare root transplants as we do. For more delicate seedlings February-June, Bryan likes soil blocks on benches under shadecloth or rowcover tunnels.
Watering by hand must be a joy once the farm gets to the point of only needing water for new seeds and new transplants. We’re not there yet, and so must continue dealing with drip “irritation” and sprinklers.
The crop rotation chapter includes a planning chart showing what goes in each plot when throughout the course of a year. The system includes flexibility: if a crop continues to grow well in a spot, it doesn’t get rotated. That challenges one of my cherished beliefs! My next challenge came with the information about the influence of the moon on crop growth. I have raised eyebrows myself, claiming that frosts are more likely with a full moon. It sounds so woo-woo, but it fits my observations. Perhaps Bryan is more observant of details, more woo-woo than me, or both. I’m happy he acknowledges that sometimes a crop needs to be planted regardless of lunar position.
Next is a valuable chapter on soil fertility and crop health assessment. This is an area I would like to practice in more. Not just testing pH and the main minerals, but also the Brix measurement of sugar in the crop sap, the electrical conductivity, and soil compaction. Bryan gives a good explanation of cation exchange capacity (the nutrient-holding capacity), and points out the challenges of achieving a good high CEC and then of adjusting the elemental nutrient balance: you need large amounts of material to bring the elements into balance, compared with a low CEC soil. And never forget: “the objective is not to balance a soil test but to get results in the field.” Strong biological activity can outweigh chemical element imbalances.
A slightly acid pH of 6.5 helps cations be more available to the plants: the acidity favors a higher level of fungal activity, which releases nutritional elements held in bonds that resist bacterial action.
Phosphorus buildup is an issue for us growers who use a lot of compost. It is hard for labs to assess phosphorus levels, because many factors influence its soil availability. Compost grows strong plants which in turn reduce water pollution, including phosphorus. Looking at the big picture leads to different solutions than focusing down on soil phosphorus content. Soils high in OM often test high in P because the test includes all the P-containing living fragments. Water-quality regulators are focused on phosphorus contamination of waterways above and beyond that of other pollutants like excess synthetic nitrogen fertilizers and industrial byproducts.
The information on composting is thorough, and Bryan recommends up to 100 tons per acre for a new vegetable patch. Thereafter, 30 tons or more per acre pre-plant. There is a good comparison of various organic fertilizers, and instructions on making bonemeal after cooking meat. There are fish fertilizer recipes which (to my surprise) call for “unprocessed brown sugar.” When I was a hippy grocer in the 70s, our sugar supplier told us there was really no such thing as unprocessed brown sugar – all brown sugars are white sugar with various proportions of molasses added back in. There’s no more nutritional value in brown sugar than in white sugar. Even “raw” sugar isn’t raw. I guess the only unprocessed sugar is a length of sugar cane or a chunk of sugar beet! Is sugar a big evil, like a synthetic fertilizer, that we don’t want to add to our gardens, or does it have a place?
Some growers apply raw manures, or uncomposted food byproducts directly to the soil, (“sheet composting” or “trench composting”) in the fall for crops the following spring. It’s certainly less work than making a compost pile, but is the result as balanced as a composted mix? Everyone has to make their own decisions. Bryan takes a thoughtful look at these options, and milk, seaweed, charcoal, vinegar and more.
He gives us his precise recipes for liquid and solid feeds for seed-starting, for young plants, and for flowering plants; recipes to be modified by growers for their own conditions. He adds particular ingredients to the base recipe of 30% wood chips, 20% dead leaves or straw, 40% cattle manure and 10 % vegetable scraps.
After this we get into the production of Biodynamic preparations, which do seem to require faith. Working barefoot and stirring a bucket of potion to create a vortex is a step too far for me. But for the grower who wants to learn about these techniques from an expert farmer rather than another beginner, this is a good place. Here are recipes for Biodynamic horsetail tea and Preparations 501 (ground quartz) and 500 (horn manure) as well as Oriental Herbal Nutrient (OHN), a fermented herbal preparation, and Fermented Plant Juice (FPJ) from Korean Natural Farming. “With this stirring comes the opportunity to impart the forces of will or prayer into the material, so this is a time of concentration or maybe a song.”
Next are the Indigenous Microorganisms (IMO). This is part of Korean Natural Farming, and involves “farming” captured forest microorganisms (most noticeably, fungi) with a bait of cooked grain. There are four stages. Making IMO #1 involves incubating cooked grain (mixed with sugar) perhaps with some duff from the forest floor. The lidded box is set in a forest, covered over with more duff, and left for a week. Once white fungal mycelia (and perhaps other colors of fungi) cover the surface of the grain, you have IMO #1. The box is brought back from the forest and further processed to produce a large pile of active life.
Mix IMO #1 with sugar 1:1 by weight in a crock, cover it with paper and keep at room temperature for a week. This is IMO #2. To make IMO #3, stir this material in water and mix with bran. Pile the damp material on the forest floor, cover with wet leaves, straw or cardboard and tarp if it’s rainy. The pile heats up and produces more white fungal growth. After about 5 days, make IMO #4. Add an equal volume of soil to the bran pile and mix in. After about a week the material is ready to use. IMO #4 can be spread directly on the beds at 5 gallons per 250 ft2, approximately every other year. Or it can be used as a foliar feed. It acts as a catalyst to grow stronger plants. Improvements to the soil can include better aggregate structure, and better release of nutrients.
Weed, insect and disease control come next in the book, necessary but not directly income-earning aspects of farming. Increasing crop health and vitality for the long term is of fundamental importance here. There is a sense in which pests can be useful: as indicators of an imbalance that the grower would do well to address.
Reducing the weed seed bank is a long-term improvement. Destroy weeds as they germinate, and do not bring up weed seed by tilling. Try not to import weed seed with brought-in materials. Since Bryan was able to stop tilling, galinsoga no longer pops up [envy!]. Crop rotation can help break weed cycles by altering the growing environment. Switch between cool weather and warm weather crops, soil-covering crops and vertical crops, and keep roots in the ground all the time.
Stale seed beds and shallow hoeing can kill weeds without tillage, and solarization can kill not only germinated seeds but ungerminated ones near the surface. Mulches can prevent weed seed germination. Good hoeing technique and tools can remove the weeds that still pop up.
Don’t over-react if problems arise. Monitor pests or diseased plants and count a sample. Determine if the pest numbers warrant your intervention. Also determine if it’s too late to save that crop. Learn if managing the crop differently next time might make it more resistant to pests or diseases. It might take a season or two for changes to pay off in terms of stronger crops. Carefully look for any improvement, as an indicator that your actions are steering things in the right direction.
Beneficial insects, rowcovers, insect netting, shadecloth, shelterbelts and other kinds of crop protection all help crops grow stronger. I learned that our friends, the Cotesia glomerata wasps that parasitize brassica caterpillars, and overwinter as pupal cocoons on the undersides of brassica leaves, will hatch out in spring on the very day the overwintered brassicas start to flower. The 20-50 day lifecycle needs brassica flowers, so don’t be in a hurry to cut down all your bolting greens! The flowers provide nectar for the adult wasps. The leaves, as we know, provide food for the caterpillars, which provide the host for the wasps to lay eggs in. The wasp larvae feed on the caterpillar until it dies, then pupate.
There’s an incredible National Geographic video of this cycle, showing parasitic wasp larvae swimming around inside a caterpillar, bursting out through its skin. The weirdest bit is that it is the dying caterpillar that spins the protective cocoons around the pupating larvae. And us who plant the brassicas that feed the caterpillars! Who is the farmer and who is farmed?
The next chapter is on organizing things to produce vegetables year round. Off-season growing takes more attention and understanding than growing the crops at the easiest time of year. And can bring higher prices and more appreciation. People do want to eat year-round! Protective structures can earn their keep. Tobacco Road Farm uses lots of low tunnels in their snowy winters. Snow cover is actually a benefit to low tunnels, holding the covers in place, and providing insulation. In our climate, I think hoophouses work better. Because our winter weather switches back and forth from cold and icy to warm and sunny, we would spend a lot of time ventilating low tunnels. Without snow cover, we suffer wind and radiation losses through the clear plastic on cold nights.
We need to harvest more frequently than growers in colder climates (not complaining!), and the stooping over, opening and closing of low tunnels gets tiresome. We appreciate walking around in our (no-till) hoophouse, where all the crops are visible at once. Different climates call for different solutions. If you are working with winter low tunnels, read this book and learn how to customize a snow shovel for clearing snow from the tunnels, by rounding and smoothing the corners of the blade. And here are tips for charring sawdust to melt thicker snow. They use a pump to blast a slurry of charred sawdust, salt and molasses over the tunnels. Sounds like a fun winter activity!
Bryan points out how healthy, sturdy crops will have a longer shelf life after harvest, paying back the year-round attention to soil and environmental health. Here are tips on ergonomic harvesting of small crops at ground level (rest one elbow on your knee) and efficient harvesting (while cutting, decide where to make the next cut). The speed of decision-making can be the bottleneck in harvesting, so practice to speed your decision-making.
Why do we grow vegetables? To meet basic human needs for health and happiness; to provide healthful foods, with the potential for job satisfaction and happiness. Sometimes slogging through and finishing a project is the most efficient. Sometimes switching to a different plan is more efficient (or at least, effective). Efficiency includes having a plan and having the flexibility to change plans.
The Further Reading includes a list of twenty books, and I am honored to be among those 26 authors. There is only one other woman among the authors. Bargyla Rateaver is from Madagascar, and with her son Gylver Rateaver, she wrote The Organic Method Primer in 1993. Some reviewers and obituary writers refer to Bargyla as “he”. Farmers are not all of one gender (or of one color). Thanks Bryan, for including some of the diversity that exists.
At the beginning of this review I said it was not a “menu” book, but a “specific method” book. Then I found myself picking and choosing from the ideas Bryan presents. It really isn’t a fixed meal. There is something everyone will love in this accomplished work. You don’t have to add all the Special Sauces.
PART THREE: Potato pests and diseases (this one, June)
PART FOUR: Harvesting potatoes (July)
PART FIVE: Storing potatoes (August)
PART SIX: Planning to grow potatoes again (September)
I have a whole chapter about potatoes in Sustainable Market Farming, where most of this information can be found.
See Root Crops in June for info on digging up new potatoes, if you can’t wait for them to mature!
See The Potato Association of America, Commercial Potato Production in North America 2010 for lots of interesting info, including planting in hot weather. (But hurry up, you need to have enough growing days left in the season to get them to maturity.)
Organic Integrated Pest Management involves tackling pest problems one step at a time with ecologically-based practices, starting with actions to reduce the chances of the pest ever getting a grip on your crops. I recommend the ATTRA online publication Organic Integrated Pest Management. Each of the 22 pages is a poster, complete with good photos and concise clear info. Because nightshades have a lot of fungal, bacterial and viral diseases, it pays to take action to minimize the chance of diseases attacking your plants.
Integrated Pest Management in Organic Field Crops Webinar from eOrganic
Biological IPM disease and pest reduction strategies for potatoes
Cultivate strong crops and provide healthy soil, sufficient space, nutrients and water, suitable temperature, and soil pH.
Choose varieties that resist the pests and diseases you most expect. Improve the soil tilth, drainage and aeration. Chisel plow or broadfork to break hardpan, or grow deep-rooting cover crops ahead of your potatoes. Maximize air circulation around the plants. Choose a bright, breezy location (avoid frost pockets as they also collect dew), orient the rows parallel to prevailing winds and give the plants plenty of space.
Add compost and cover crops to build fertile soil to support strong plant growth and help increase the diversity of soil microorganisms, building naturally disease-suppressing soil. Use foliar sprays of seaweed extract, microbial inoculants or compost tea to boost general disease resistance. Consult ATTRA for compost tea Brew one part of compost to 5 parts water by volume for 14 days before spraying.
Practice crop rotation to reduce the chances of pests and diseases carrying over from one crop to the next. For potatoes, it’s best to rotate away from nightshade crops for at least three years. We don’t manage this ideal of one year in four. In our ten-year rotation, three of our ten years are nightshades (one paste tomatoes and peppers, two plantings of potatoes).
Practice good sanitation. Clear old crops promptly, so they don’t act as a breeding ground for pests or diseases. Avoid smoking, especially near nightshades, and have smokers wash their hands with soap or milk before working with potatoes. Tobacco can spread tobacco mosaic virus (TMV) to nightshade plants. Avoid working potato plants while the leaves are wet. Remove and destroy diseased plants, especially for late blight. Clean tools in between use in one field and another. When the harvest is finished, till the tops into the soil to speed decomposition, or remove and compost or burn them if growing on a small scale.
Remove nightshade weeds (e.g., horsenettle, jimsonweed and black nightshade), which can be alternate hosts for pests and diseases.
Prevent soil splash-back onto leaves, to reduce outbreaks of soil-borne diseases. Use drip irrigation rather than overhead sprinklers.
Cover or protect the plants physically from the pests
mulches to stop soil-dwelling pests (CPB) moving up into your crops
netting or rowcover to protect from airborne pests (leaf hoppers, blister beetles)
Provide habitat for natural enemies and other beneficial insects. Farmscaping with sunflowers, peas, vetch, buckwheat or small grains, to encourage ladybugs and lacewings, can make insect control unnecessary in a good year. Ground beetles and bats can consume surface and air attackers before you even need to look.
Monitor your crops regularly at least once a week and identify any pests you see.
Introduce natural enemies of the pest (bacteria, fungi, insect predators or parasites). Try biofungicides for use against some diseases. F-Stop, T-22G Biological Plant Protectant Granules or other forms of Trichoderma can control Rhizoctonia, Fusarium and Sclerotonia. Soil-Gard (Gliocladium virens) can work against Rhizoctonia. Bacillus subtilis works against Rhizoctonia, and Sclerotonia. Mycostop (Streptomyces griseoviridis) can be used against Phytophthora, Alternaria, 35% hydrogen peroxide diluted to a 0.5–1% foliar spray solution may help control early blight. 1% solution = 3.7 oz in 124.3 oz water to make one gallon (1 ml:33 ml). There are commercial products such as Oxidate that are based on hydrogen peroxide, which is corrosive and challenging to handle.
Hand pick (or trap) and kill the pests if the pest population is above the action threshold. Many fruit and root crop plants can take 30% defoliation before suffering any loss of yield. Where the crop is the foliage, this may be too much, but people don’t east potato foliage!
Use biological controls (often derived from natural enemies) if the damage is still economically significant after trying the earlier steps in the process, including Spinosad or Bt.
Potatoes can be attacked by more than 150 insect pests. But don’t despair! In each region there are only a few species that could cause unacceptable losses of yield or quality. These losses can result either directly from the insects or indirectly by transmission of diseases.
Colorado potato beetle is the most common pest that potato growers get to deal with. The pink blob-like larvae of this beetle can eat enormous amounts of potato leaves while growing into bigger pink blobs. Left alone they can kill a planting. Acceptable amounts of defoliation without causing loss of yield are surprisingly high: 50%–75% of the top leaves on a young 6″–8″ (15–20 cm) plant, 25% on a 12″–16″ (30–40 cm) plant, a mere 10% at the critical full bloom stage (when the tubers are sizing up), and up to 25% once full grown. As with many pests, having a few of them is not important — it’s all about the numbers. Action to control CPB is only needed if the number of adults or larvae is higher than 1.5 per plant or egg masses exceed one per ten plants.
Crop rotation is effective, because Colorado potato beetles overwinter as an adult in the soil and when they emerge they have to walk around searching for a potato plant. CPB can have 1-3 generations a year. Even where two or three generations are usual, a significant portion of the summer generation adults go directly into the soil and become dormant. Eggs are laid in clusters of 20 or more. They look like ladybug eggs but are a stronger orange color – don’t kill the wrong ones! The beetle can go from egg to adults in as few as 21 days. There are four larval instars, with 75% of the total foliage destruction caused by the final and fattest instar.
Mulching with hay or straw can prevent CPB finding your potato plants – we never find them on our summer planting. Our unmulched spring planting is a different matter. I scout that field once a week, counting adults and larvae on a hundred randomly selected plants. As soon as I see more than 50 adults or 150 large larvae or 400 small larvae per 100 plants, I unpack the sprayer. I do a spraying with Spinosad, a fermentation product of a soil bacterium. It kills insects by over-stimulating their nervous systems. Spinosad kills a wide range of helpful and harmful insects too, so spray in the early morning or late evening when bees are not flying. Shake the bottle well, and mix following the instructions. Clean and triple rinse the sprayer. Do not flush in the creek or pond. Repeat in 6 days, but only if needed. Usually one spraying is enough, although I continue weekly checks. In the South, there can be three generations of CPB each year, so stay vigilant.
Prior to using Spinosad, we used Bt. The version of Bt for CPB nowadays is Bacillus thuringiensis var. tenebrionis. The kurstaki strain (such as Crymax) generally available in small quantities previously is genetically modified, so we stopped using it, not wishing to be part of any support for GMOs. Neem and Beauvaria bassiana can also kill CPB larvae.
Flaming when the potatoes are less than 8” (20 cm) tall, is another effective control measure for CPB. Choose a warm sunny day when the pests are at the top of the plants. Flaming can kill 90% of the CPB adults and 30% of the egg masses, according to Colorado Potato Beetle: Organic Control Options – ATTRA
Insects with piercing-sucking mouthparts damage potatoes by physical injury to the leaves, sucking out phloem, injecting their toxic saliva and possibly transmitting diseases. While potatoes can grow new leaves, there is still damage to plant health. Direct injury by sap-feeding insects can kill the plant. Soil-dwelling insects have only minor effects on yield, generally, but can reduce tuber quality and storage life.
Aphid-transmitted viruses cause greater losses than all other insect-related damage together. There are at least 9 aphid-transmitted potato viruses. Aphids can be reduced by farmscaping, planting flowers which attract ladybugs, lacewings and other aphid-eating insects.
Potato leafhoppers are a bad problem in central and eastern North America. They overwinter on the Gulf Coast. In spring, flying adults are transported north on upper level airstreams. Yield loss can occur before visual symptoms are obvious. Leafhoppers can cause leaves to shrivel and die. The initial effects are reversible if leafhoppers are controlled before leaf tissue is destroyed (“hopperburn”). By reducing the green leaf area, hopperburn affects photosynthesis and growth. The most vulnerable stage is when the tubers are bulking up. Leafhoppers can also transmit diseases. Trichogramma wasps parasitize leafhopper eggs. Garlic with insecticidal soap, sprayed early in the morning, especially on the undersides of the leaves, can control hoppers.
Potato psyllid occurs in the western U.S. Damage to the roots and tubers is caused by feeding nymphs, which can cause psyllid yellows. The first symptoms of psyllid yellows include stunting, loss of green color, leaflet distortion, reddish discoloring of new leaves, and the appearance of aerial tubers. Early action can stop and even reverse the damage. Adults cause little to no damage underground.
Wireworms (click beetle larvae) can tunnel through the tubers. Wireworms can live for 1-3 years, so crop rotation is important. Avoid planting potatoes the first year after turning under pasture or lawn. If you expect to have wireworms, plant small whole seed potatoes rather than cut pieces. Cut slices of potato can be used to trap wireworms (dig up the trap pieces each day and kill the wireworms.
Cutworms can eat the leaves from the bottom of the plant up (the opposite approach from CPB larvae). Once the plants are fully grown, up to 75% loss of lower leaves is unimportant. At earlier stages, if any cutworm damage is seen, dig around the stem, find and kill the cutworms.
Blister beetles can cause trouble later in the season, skeletonizing leaves and spreading a wilt. They contain cantharadin, which can cause blisters on the skin of unwary workers. Blister beetles can be trapped in crops of chard or beets next to the potatoes. The beetles are easier to see and catch in the trap crops than in potato foliage. If there aren’t too many it may be worth putting up with them, as their larvae are carnivorous and eat grasshopper eggs.
The potato tuber moth damages both foliage and tubers during growth, but the biggest losses occur in storage. Larvae inside the potatoes can continue their development in storage, filling the tubers with frass and letting in decay organisms. When commercial infestations are high, the crop is not worth harvesting because of labor costs to cull out the infested tubers.
Nematodes can be deterred by choosing appropriate preceding cover crops, or by applying 1-2 tons/ac (2240-4480 kg/ha) of crushed mustard seed meal to the soil before planting. This will also reduce early weeds and act as a fertilizer.
Before a plant can become diseased, three conditions must exist: a susceptible host, a disease organism, and a suitable environment for the pathogen. The choice of the disease control method should be based on an accurate identification of the pathogen and the disease.
Late Blight (Phytophthora infestans) is by far the worst disease to afflict potatoes. This is the disease that contributed to the famine in Ireland (caused by the profiteering of the English land-owners, who sold the barley and left the tenant farmers to subsist almost entirely on potatoes). The disease is caused by a species of a fungus-like oomycete or water mold (previously considered a fungus, now reclassified as protozoa) that blows in on the wind. It is worse in warm wet weather with cool nights. Late blight starts as “water-soaked” spots on the leaves. These expand into gray-black “scorched” areas, sometimes with a dotted white mold growth, especially on the underside of the leaves. Cut stems reveal a dark circle of infected tissue. The disease spreads rapidly, turning plants black, as if badly frosted, and can kill an entire planting in ten days unless stopped by hot dry weather.
The best defense is to always remove volunteer nightshades from your fields and compost or bury all crop debris. The disease spreads via cull piles, nightshade plants and petunias — it needs live plant material to survive. If you find volunteer potato plants popping up in early spring, it is best to pull them up! Spores survive winter in warmer climates and then blow north and uphill. Preventive action may be taken with sprays every five days of (toxic) copper products, hydrogen peroxide, Bacillus pumilus or Bacillus subtilis products.
If Late Blight occurs late enough in the season, you can save your crop by mowing off the foliage, raking it off and disposing of it, and leaving the field untouched for two weeks before harvesting whatever potatoes have grown. This prevents the spores getting into the soil and infecting the tubers. Disposing of large amounts of blighted foliage is no easy task. When I had to deal with Late Blight, back in the 70’s, we made a fire and gradually added more tops as the previous ones burned. This was a very smoky fire, polluting, and no doubt contributing to global warming. Digging a big hole and burying it all is probably better.
Early Blight (Alternaria solani) is a common fungal disease, which mostly affects stressed or older plants. It starts as small brown spots on the lower leaves, which conglomerate into brown blotches that are restricted by the leaf veins, and so they can be angular in shape. The lesions have a bullseye appearance – concentric circles with a yellow halo around each one. During warm humid conditions, the fungus steadily defoliates the plants, reducing yields. The disease is seed-borne, soil-borne and airborne, surviving on plant debris and nightshade weeds. Early blight (Alternaria solani) can appear late in the season, not just early, despite the name. The manifestation of blight symptoms can be minimized by growing strong healthy plants, supplying sufficient water, and spraying with compost teas. The beneficial fungus Trichoderma harzianum can give good results.
Black Scurf or Stem Canker fungus (Rhizoctonia solani) is worst in cold wet soils. Early in the season it can cause sprout death. On older plants, red-brown stem lesions develop into cankers, and the infection can spread to the tubers, which then become cracked and misshapen, and may have dead tissue at the stem end. There may be firm black sclerotia (small dried reproductive bodies) on the tuber. In future, get disease-free seed potatoes and wait for the soil to warm a bit before planting.
White Mold (Sclerotinia sclerotiorum) on the vines. If you want to prevent this in future, you could dust the seed pieces with the commercially available fungal antagonists Trichoderma viride and Trichoderma virens.
Potatoes: Yes, it is OK to plant potatoes in June, up until late June. Count back from your first frost date the 80-100 days or whatever your chosen variety needs to mature. See my post on planting potatoes. We buy our seed potatoes for the June planting in April, before local suppliers sell out of spring stocks. We store them in our walk-in cooler until two weeks before the planting date. I recommend some special techniques for summer potato planting. See the Other Root Crops Tasks section below for more details. An advantage of summer planting is that the harvested crop need only be stored from October or November, not over the hotter months.
Sweet potatoes: It’s still OK to plant sweet potatoes in June in central Virginia, and if you live in a colder climate, you probably wouldn’t even try to plant in May. It is best if the soil temperature is 65°F (18°C) for four consecutive days before planting. See my post on sweet potato planting
Carrots: We direct sow our seventh bed of carrots in mid-June. It can be hot and the challenge is to keep the soil damp. Unlike some other crops (lettuce and spinach come to mind), carrot seed will germinate just fine at high temperatures. Shadecloth can help keep the soil damp, or you can just water a lot. You won’t need to do daily watering for long: maybe only 4 days. See Root Crops in May.
We only sow in June and July if we really need carrots, as hot weather impairs the flavor. Our hope is always that we will have grown enough between February and May to last till late October, and have bags in storage in the walk-in cooler. Sow carrots whenever the soil is below 95°F (35°C), so long as you can keep the surface damp. In summer we flame carrots on day 4 after sowing, because we have found that carrots can emerge on day 5 in summer temperatures, despite longer times given in the charts. See Root Crops in May for more about sowing and growing carrots, including pre-emergence flame weeding.
See the Special Topic below for more on growing carrots.
Warmer climates with later frost dates than central Virginia: you may still be able to plant crops we gave up on in May.
Colder climates: you may need to sow rutabagas, which we don’t need to do till July.
Root Crops to Harvest in Central Virginia in June
Beets: We like Cylindra best (55 days to maturity, OP). Detroit Crimson Globe is said to maintain better flavor in hot weather than most others, which can develop off-flavors. Remember as you harvest beets to check the leaves, as possible cooking greens too.
Later in the summer ours develop spotty holes from Cercospora Leaf Spot, and become unappetizing, but in early June they are usually fine. We like to clear all our spring beets by the end of June.
Store beets at 32°F (0°C) and 95% humidity. Trimmed beets keep well in perforated plastic bags under refrigeration. We have “rediscovered” stored bagged beets at the back of the refrigerator 9 months or so later and they were in fine condition.
There are also non-electric storage methods for roots, but these mostly rely on cool soil and cool air, so I’ll write about those when we get to fall. If you have a root cellar with a good temperature, you can use that. I have a chapter on root cellars in Sustainable Market Farming.
Carrots: Our second carrots (sown in late February) and third (sown in mid-March) will be ready to harvest in June. Possibly also our fourth sowing (late March), by the end of June. Don’t leave them in the ground too long, or they will get fibrous and woody. No fun!
Fennel bulbs: if you planted those in spring, they will be ready in June in central Virginia. If you didn’t grow this, consider it for fall, when it is easier to grow it without danger of it bolting. I wrote about fennel as a hoophouse crop in The Year-Round Hoophouse.
Kohlrabi: In our zone 7 climate, kohlrabi, like other brassicas, can be grown in spring or fall. So you can buy seed now and plan for kohlrabi in October, November, or into the winter if you store it. In spring we harvest kohlrabi from May 10 to June 30, when they reach 2-3” (5-7.5 cm) in diameter (or even up to softball size). The base of the globe can be quite fibrous, so cut either the wiry root just below the soil surface, or cut higher, leaving a small disc of the globe behind, attached to the root. We definitely need to dig all our spring kohlrabi by the end of June at the latest, or they get too woody. Unlike carrots and turnips, fennel and kohlrabi can successfully be transplanted.
Potatoes: In mid-June we can start harvesting spring-planted potatoes as delicious “new” potatoes. Check under a plant to see how big the potatoes are. If they are big enough and you aren’t worried about reducing later final yields by starting early, go ahead and dig some. It doesn’t matter that the tops haven’t died. These new potatoes will have shreds of thin skin, not the firm skins needed for potatoes to be storable, so just dig them as you need them. If this is your first year growing potatoes, you will be amazed at how good they taste boiled with a sprig of mint. So much tastier than store-bought!
Turnips: They are among the fastest growing crops other than leafy greens. We harvest our spring turnips gradually, pulling the biggest and letting the rest grow bigger. By the end of June, though, we need to have them all up and if we have plenty, we store some in perforated plastic bags in the walk-in cooler, until mid-July. Turnips will keep for about 4 months at temperatures close to freezing and humidity of 90-95%. Higher humidity will make them rot.
Other Root Crops Tasksin Central Virginia in June: Summer Potatoes
In early June, in preparation for mid-June planting, we chit (pre-sprout) our seed potatoes for two weeks in trays in the light. Unlike chitting in February and march, the potatoes don’t need supplemental heat at this time of year. The method is the same as I described in my post Planting Potatoes. Let all the sprouts grow. For warm-weather planting, one sprout per seed piece is usually sufficient – the chance of frost is over, and “spare” shoots are not needed. Tubers with many sprouts can be cut into many seed pieces, which can save money. See the Planting Potatoes post for details on Cutting Potato Seed Pieces.
In warm conditions, deeper planting, hilling and thick organic mulches all help keep the plants cooler, as does irrigation. To help keep the soil cool while the potatoes are growing through the heat of July, August and September, we mulch with spoiled hay. (Straw would be nice, but this is not a grain-growing area). We bale our hay in the big round bales, and we have almost a quarter acre of summer potatoes to cover, so it is by far easier for us to unroll the bales before the potato shoots emerge from the soil. To lay the mulch by hand around the potato plants after they come up would take way too much work on our scale. Home gardeners may use loose mulch and tuck it in around the plants later.
So, in order to mulch the day after planting, we cover the seed pieces with soil, using the tractor and the hiller. (When we used our BCS tiller for this, we simply tilled between the rows, which leveled the field and covered the potatoes well enough). Then we hill, and unroll round bales of spoiled hay immediately, or the next day. Potatoes emerge quickly in warm weather! Hilling is tricky without any visible signs of where the potato pieces are. We have sometimes used stakes and ropes to mark the rows, or else flags at the ends of the rows, and crossed fingers as we drive the tractor and ridger down the field.
Unrolling hay bales is close to an Olympic team sport! We line up the bales (using a tractor and hay spike or forks) shoulder to shoulder at the uphill end of the patch. Our land is almost flat, but even a slight slope makes a noticeable difference when pushing a hay bale, so do start at the top end! Next we study the pattern of the grass stems in the ends of the bale, and if needed twizzle it round 180 degrees on the ground, so that it will unroll itself when pushed. We cut and remove the twine, then two or three people start it rolling. Once it’s going, each bale has two people unrolling it, and eventually it gets small enough for one person to handle and the other can go back to the top and help start another bale. We try not to walk on the hills and we try to lay out the hay like wall-to-wall carpeting, without gaps.
About 16 days after planting, in late June, we do a walk-through, one person per row evening out the mulch, and freeing trapped potato shoots. Everywhere we expect to see a potato but don’t, we part the mulch carefully, seeking pale flattened shoot. If we find one, we rearrange the mulch a little, so that the shoot is exposed to the light, but the soil is not. It’s not necessary to expose the whole shoot – even a little bit of stem is enough for the plant to reorient itself and be fine.
Later in the season we’ll need to weed the potatoes. I haven’t been mentioning it, but weeding is important for all crops, especially direct-seeded crops.
Special Root Crop Topic for June in Central Virginia: Carrot Types
These days there are many fancy colored carrots, but my preferences all lie with bright orange carrots, rich in beta carotene. We have tried growing a few white, yellow and purple varieties, but frankly I found them all very disappointing, as far as flavor and succulence. They tended to be scrawny! All carrots sweeten up when days are warm and nights cool.
Carrots come in five different carrot types based on their shape and size. The factors influencing your choice will be soil type, climate, market, and harvest time and method.
Danvers are a long, thick-rooted cylindrical shape tapering to a point. They often have a yellowish core. The leaves and taproot are both longer than Chantenay types. They are suited to high production of bulk carrots and widely used in processing. They store well. They are more tolerant to poor soil, but grow best in deep, sandy loam. Making raised beds helps.
Varieties: Danvers (OP), Healthmaster (F1), Danvers Half Long (OP), Danvers 126 (OP) Season: spring to fall. Summer in cool climates Days to Maturity: 70-80 in spring, 80-110 in the fall
In central Virginia, zone 7, on a sandy clay loam, we grow Danvers 126, a sturdy open pollinated variety.
Nantes are medium-length, straight, cylindrical roots 5-7” (13-17 cm) long with blunt tips and sparse foliage. A very quick growing variety. Nantes types have sweet, juicy, tender, crisp, almost red flesh; but only limited storage potential, and they are somewhat brittle. They contain few terpenoids, the volatile flavor compounds we think of as “carroty”. When poorly grown, they can be watery and bland. Nantes do best inloose, sandy soil or raised beds enriched with organic matter
Varieties: Early Nantes (OP), Scarlet Nantes (F1), Bolero (F1), Mokum (F1), Napoli (F1) Season: spring to fall; summer if not too hot Days to Maturity: 55-70 in spring, 60-75 in fall
We have grown the 75-day Bolero, a high-yielding carrot that stays sweet even in storage. 6-7” (15-18cm) long, with a 1 ½” (4cm) crown. It looks a bit prettier, and has slightly better flavor than Danvers, but ultimately we decided the extra cost of the seed was not worth it to us. The resistance to Alternaria or Cercospora found in Bolero has been important for our fall crop.
Imperator –Most commercial growers produce this type. They are similar looking to Danvers, but bigger: longer, thicker in width, with stocky shoulders and strong fast-growing tops. They store very well. They perform best in deeply worked sandy loam soil. In rougher soils, they develop a slightly fibrous texture. Imperator types contain more terpenoids, and can be prone to bitterness if something goes wrong. Many hybrid varieties are a cross between Nantes and Imperator types.
Varieties: Sugarsnax (F1), Autumn King (OP) Season: spring to summer in cool climates, or summer to fall Days to Maturity: 55-100 in spring, 80-110 in fall
I have grown Autumn king in England and it was a very reliable variety.
Chantenay:short and broad conical roots with rounded tips, 6-7” (15-17 cm) long. Very vigorous top growth. Rich, sweet flavor. Chantenay store extremely well. They are the best type to plant in shallow, rocky or heavy clay soil due to their shape. Of course they also do well in better soils! These are a great choice for those gardening in containers. It is important to harvest at the appropriate length because they become woody and poorly flavored if harvested too big.
Varieties: Red Cored Chantenay (OP), Kuttiger (white, OP), Kuroda (OP) Hercules (F1), Carson (F1) Season: spring to early summer, midsummer to late fall Days to Maturity: 55-70 in spring; 70-110 in fall
I have grown Red CoredChantenay (65 days), a blocky variety with a blunt tip, 5″ (13 cm) long and 2″ (5 cm) at the shoulder. It resists splitting. The flavor of Chantenay types has been described as “parsley-like”. Kuroda types have a drier, creamier flavor. They are tolerant to Alternaria.
In the past, before the soil here had been improved, we had to grow shorter carrots, as the long ones would break in the tight soil. Most of the varieties recommended for clay soils are small, as well as short. Nearby at Southern Exposure Seed Exchange, they have had astounding success with Oxheart (90 days, OP) a large, squat, chubby Chantenay type, with shoulders reaching 5″ (13 cm) across and 3-4″ (7-10 cm) long with a full carrot flavor.
Miniature: round, cylindrical or tapered roots less than 5” (13 cm) long; crisp texture and frequently quite sweet This grouping includes carrot varieties that are shaped like radishes and miniature regular-carrot shaped ones. They work extremely well in containers due to their short taproot; They will grow in any fertile soil that drains well They have only limited storage potential.
Varieties: Thumbelina (OP), Little Finger (OP), Parmex (OP), Atlas (OP), Babette (OP), Romeo (OP), Paris Market (OP). Season: spring to early summer, late summer to fall Days to Maturity: 50-60 in spring, 60-70 in fall
Johnny’s has a pictorial comparison of some varieties on their website, under Growers’ Library/Vegetables at for maincrop and storage carrot varieties, the tiny round Atlas, Romance, Hercules, Bolero, Nectar and the long slender Sugarsnax; and for early varieties, small Adelaide, Yaya, Mokum and Napoli.
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Birth of Assassin Bugs
Debbie Roos, an Agricultural Extension Agent at Chatham County Center, North Carolina Cooperative Extension and the founder of www.growingsmallfarms.org is a wonderful photographer,. She recently reposted this.
A couple of years ago I posted a series of photos on my Growing Small Farms website showing assassin bug nymphs emerging from their eggs. It was an amazing thing to witness and not something you see every day. Folks really enjoyed seeing the photos back then and since it’s spring and time for more to emerge I thought it would be fun to share the photos again now that so many people are spending so much time at home!
Be on the lookout for these egg clusters on your property and you may even get lucky and witness the birth of an assassin!
Steve Albert has an informative website, Harvest to Table, and this post on quick-growing vegetables includes some warm weather crops like bush green beans and sweet corn. It includes names of fast-maturing varieties.
This magazine is “a quarterly publication committed to giving you in-depth expertise to bolster your organic garden each and every season. Roll up your sleeves and learn soil-boosting strategies, permaculture practices, and more! Formerly known as Heirloom Gardener.”
Margaret writes about home-grown seedlings, finding flavor, choosing between hybrids and open-pollinated varieties, saving seed, good tomato-hygiene, monitoring for pests and diseases, pruning, staking or otherwise supporting the plants, and dealing with the weather.