Time to Sow More Fall Brassica Crops

 

Young tatsoi plants.
Photo Bridget Aleshire

See my recent post for info about fall broccoli and cabbage. Here I provide some more information and discuss other brassicas you could grow in the fall.

Temperature and Timing for Fall Brassicas

  1. Germination: Brassica seeds will germinate at soil temperatures from 41°F (5°C) to 95°F (35°C). 41°F (5°C) can take 45 days for some brassicas, but in summer and fall, this isn’t the end of the thermometer we worry about! In summer and fall, soil temperatures are enough to germinate brassicas in 3-10 days. Optimum soil temperatures for germination are
  • 77°F (25°C) for most Asian greens, broccoli, Brussels sprouts, cauliflower, collards, kohlrabi, pak choy;
  • 86°F (30°C) for cabbage, including Napa cabbage, kale, turnips and rutabagas;
  • 68°F (20°C) for mustard greens, and perhaps arugula (which might do better even cooler)
Vates kale seedlings for bare-root transplanting outdoors.
Photo Pam Dawling
  1. Cold-Hardiness: Consult this list of winter kill (air) temperatures for brassicas, for the crops you are growing.
  • 32°F (0°C):  some cauliflower curds, some pak choy
  • 27°F (-3°C): many cabbage varieties
  • 22°F (-6°C): some varieties of arugula
  • 20°F (-7°C): broccoli heads (maybe OK to 15°F (-9.5°C)), some Brussels sprouts, some cabbages (the insides may still be good even if the outer leaves are damaged), some cauliflower varieties, some collards (Georgia Cabbage Collards, variegated collards), some mustards/Asian greens (Tendergreen), radishes (Cherry Belle), most turnips (Noir d’Hiver is the most cold-tolerant variety).
  • 15°F (-9.5°C): some broccoli and cauliflower leaves, some cabbage (Kaitlin, Tribute), Red Russian and White Russian kales, kohlrabi, rutabagas (American Purple Top Yellow, Laurentian), most covered turnips, winter cress.
  • 12°F (-11°C): some broccoli perhaps, some Brussels sprouts, some cabbage (January King, Savoy types), most collards, Koji greens, covered rutabagas
  • 10°F (-12°C): Purple Sprouting broccoli for spring harvest, a few cabbages (Deadon), some collards (Morris Heading can survive at least one night), Belle Isle upland cress, probably Komatsuna, Chinese Thick-Stem Mustard may survive down to 6°F (-14°C), covered winter radish (Daikon, China Rose, Shunkyo Semi-Long survive), Senposai leaves (the core of the plant may survive 8°F/-13°C), Tatsoi, Yukina Savoy.
  • 5°F (-15°C): some kale (Winterbor, Westland Winter), many of the Even’ Star Ice Bred greens varieties and the Ice-Bred White Egg turnip are hardy down to 6°F (-14°C)
  • 0°F (-18°C): some collards (Blue Max, Winner, McCormack’s Green Glaze), Even’ Star Ice-Bred Smooth Leaf kale
  • -5°F (-19°C): Leaves of overwintering varieties of cauliflower, Vates kale survives although some leaves may be too damaged to use. Lacinato Rainbow Mix kale may survive this temperature.
Frosty daikon leaves.
Photo Bridget Aleshire
  1. Your Climate: Consult WeatherSpark. com to see when it begins to get too cold in your area. At our farm, the average daily low temperature on November 30 is 36°F (2°C). Decide your ideal harvest date for each crop. Although kohlrabi can take 15°F (-9.5°C), I’d want to get it all harvested by November 30.
  2. Days to Maturity: Next factor in the number of days a crop takes to reach maturity. Work back from your desired harvest date, subtracting the number of days from sowing to maturity (or from sowing to transplant, plus from transplant to maturity). Work back another two weeks for the slowing rate of growth in fall. And perhaps work back another two weeks in case in gets colder earlier than usual. This provides your sowing date.
  3. Mid-Winter Harvests: For crops that survive your winter, are you sowing to harvest in the fall, during the winter, or only in early spring? Brassicas for early spring harvest only can be sown in September or October in our climate. For those to be harvested during the winter, you need to have big enough plants going into the winter, to provide sustainable harvests (once a week in November and February and more in spring, plus maybe once a month in December and January)
Overwintered Vates kale.
Photo credit Twin Oaks Community

Various Fall Brassica Crops

In the summer we try to have a No Visible Brassicas Month to break the lifecycle of the harlequin bugs. Once our spring kale is finished, the spring cabbage gathered in, and the spring broccoli mowed down, the only brassicas are seedlings hidden under insect netting. Our hope is to starve out the harlequin bugs or at least deter them from making too many more.

We sow other fall outdoor brassicas a bit later than cabbage and broccoli. These get transplanted from our netting-covered nursery seedbeds, to our raised bed area which is more accessible for winter harvesting and more suited to small quantities.

Asian Greens

Outdoors we grow Senposai, Napa Chinese cabbage and Yukina Savoy. We have also sometimes grown tatsoi and komatsuna. Note that senposai grows quite large – give it similar spacing to collards.

We sow Asian greens for outdoors in the last week of June and first week of July, aiming to eat them before we start harvesting the ones in the hoophouse, which feed us all winter. We use Asian greens outdoors as quick-growing greens to fill the gap before our main fall greens (spinach, kale, collards, cabbage, broccoli) are ready to harvest. We don’t grow a lot outdoors.

If you don’t have a hoophouse, you can sow for outdoors later into the fall than we do, to get a longer harvest season than you otherwise would. And you certainly can direct seed them.

Yukina Savoy outdoors in December, after several nights at 16-17°F (-8 to -9°C)
Photo Kathryn Simmons

Collards

We sow collards in the first two weeks of July and transplant the bare-root transplants from the nursery bed when they are 3-4 weeks old. We plant at 18” (46 cm) in the row, with rows 12” (30 cm) apart. (if you grow a large kale, you might want similar spacing. Our Vates kale is small)

Morris Heading collards.
Photo Kathryn Simmons

Brussels sprouts

are rather a challenge in our climate, and not worthwhile. We have worked on finding the best variety (Oliver) and timing for our situation. Harvest timing is critical, as Brussels sprouts will not overwinter here.

Cauliflowers

are a tricky crop for us too. Be sure to check the “days to harvest” for each variety (they vary widely) and sow at a realistic date to get a crop before too many frosts endanger the curds. The number of days quoted for fall varieties of cauliflower already allows for the expected rate of growth at that time of year, so the 14 days for slower growth isn’t a factor. However, cauliflower is more tender, so allow for the possibility of a fall frost earlier than average.

Harvested kohlrabi, Early White Vienna and Early Purple Vienna.
Photo McCune Porter

Kohlrabi

We sow Vienna kohlrabi mid-July and transplant early August at 8” (20 cm) apart in the row, with 9-10” (23-25 cm) between rows. Later sowings (up till early September) would also work for the fast maturing varieties. Superschmelz Kohlrabi (60 days from transplanting) can also be summer sown for fall harvest. It produces 8-10” (20-25 cm) bulbs, which remain tender and an attractive globe shape.

Kale

We direct-sow two neighboring beds of kale on each of 8/4, 8/10, 8/16 and then carefully thin them, leaving one plant every 12” (30 cm). These plants grow quicker than transplants, as they have no transplant shock. Meanwhile, if we have gaps, we use the carefully dug thinnings from those beds to fill them. We want a lot of kale, and there isn’t time to transplant it all. Dividing up the sowings lets us focus on watering just one pair of beds at a time. Vates kale is the hardiest variety we have found, although I’d love to find a taller Scotch curled variety that could survive our winters (Winterbor does not survive as well as Vates).

An outdoor bed of young Vates kale Photo Kathryn Simmons

Rooty Brassicas

Radishes, rutabagas and turnips are also brassicas, but I won’t say more here. look in the further resources.

Brassica Aftercare

Brassicas started in hot conditions do not usually bolt if they have enough water.

 

Brassica seedlings under ProtekNet in August.
Photo Pam Dawling
  • Protect seedlings and the new transplants with insect netting if you have brassica leaf pests (most of do!) You can remove the netting when the transplants are well established, or leave it on.
  • Use shadecloth to keep greens cool in hot weather, or plant them in the shade of other plants.
  • To keep crops in good condition later into the winter, use rowcover. I recommend thick Typar 1.25oz rowcover, which provides 6F degrees of cold protection. I wouldn’t spend the money on anything thinner, it’s too frustrating! We do not normally use rowcover in the winter for kale and collards, as they will survive without. In harsh winters we lose the collards.

Cultivation is a simple matter of hoeing, weeding, watering as needed, and watching for pests.

Further Fall Brassica Information

Book Review: Manage Weeds On Your Farm

Front cover of Manage Weeds on your Farm

Book Review: Manage Weeds On Your Farm: A Guide to Ecological Strategies, by Charles Mohler, John Teasdale and Antonio DiTommaso. SARE Handbook 16, 2021, 416 pages, color photos, drawings, charts, $24.00

This immense book is a game-changer! A resource enabling us to understand weeds better and deal with them smartly, exploiting their weaknesses, making best use of natural and created resources.

About 300 pages comprise a directory of major agricultural weeds of the United States and Canada: about 20 grasses and sedges; about 45 types of broadleaf weeds. Many of the weeds in North America came from Europe, so the book’s usefulness is not restricted to this continent. The focus is on weeds of arable farmland. Gardens fit in this category, although the physical tools will be smaller! This part of the book is not merely to help you identify weeds, but to develop a management plan for each one.

The first part of the book is 120 pages of agricultural gold – an exploration of concepts of ecological weed management. Understanding the biology of weeds is vital to successful ecological management. (Note that I’m avoiding the use of the word control, as the authors do.) The book is “intended to provide the information you need to grow crops without synthetic herbicides, great expense or back-breaking work.” Good information is an efficient tool. Understanding more about how the biological world works will enrich your life!

This is not a book many of us will read cover to cover. It’s a toolbox. Read the first section, then seek out the profiles of your most problematic weeds and make a plan for each one. In each profile there is an identification section with good photos, a management section, a concise summary, referring back to cultural and mechanical strategies, and an ecology section with specific information leading to the recommendations in the management section.

Chapter 2, How to Think About Weeds, starts with the reminder that weeds die from various causes (any of which we can use to advantage). Seeds may fail to germinate, or get eaten. Seedlings die from drying out, disease, competition from other plants, or lack of light, or being eaten, mowed or turned under.

“The goal of ecological weed management is to arrive at a balance between birth and death that keeps the density of weed populations low most of the time and reduces them quickly when density starts to increase.”

You need to increase the death rate and reduce the germination rate of the weed seed bank, or else the population continues to increase. This demonstrates the value of understanding which tools to use in which situation. Keeping on hammering with a wrench will not work well!

Seed size is one of the characteristics of weeds that affect their successful management. Smaller seeds are easier to kill, because the seed does not provide much food for the seedling. Large-seeded crops and transplants can out-compete small-seeded weeds, if the timing of cultivation is right. There is a good explanation for why tillage prompts seed germination, which can give weeds the upper hand. Environmental cues such as soil temperature, the difference between night and day temperatures, oxygen levels, even a brief flash of light, can indicate if the seed is near the surface and whether there are competing plants up there. The cues can be very specific. Velvetleaf and tall morning-glory germinate in response to a sudden absence of certain volatile compounds which are vented from the soil during tillage. Understanding this Secret Life of Plants can help us figure strategies for specific weeds.

Different weeds germinate in different seasons, and crop rotation between spring, summer and fall crops will disrupt weed lifecycles and prevent any one taking over. Another consideration is that the same percentage of the seeds still in the soil will die each year. This means that if no fresh weed seed is added, the seed bank declines rapidly in the first few years, leaving some seed persisting for years.

The main cause of seed death is probably that seeds germinate in unfavorable conditions and then die. Secondly, seeds are eaten. Lastly, some seeds rot and decompose. Small seeds deep in the soil are unlikely to germinate. It takes a big seed to provide the resources to grow a shoot that can reach a long way to the surface. Galinsoga seeds rarely emerge from deeper than ¼” (6mm). Few seeds can germinate from deeper than 2” (5cm).

June-planted potato emerged through hay mulch. Potatoes are a C3 crop
Photo Pam Dawling

Nowadays we are learning about two photosynthetic pathways, C3 and C4. C3 plants thrive in cool, moist conditions, not needing full daylight to maximize their photosynthesis. Most cool-season grasses and broadleaf weeds use the C3 pathway.  They can increase photosynthesis (grow more) as CO2 concentration in the atmosphere increases. C3 crops like potatoes, pumpkins and soybeans will probably do better against C4 weeds as CO2 concentration increases in the climate disaster. C4 plants perform best at high temperatures, with more sunlight enabling more photosynthesis. Bermuda grass, foxtails, pigweeds, and common purslane use the C4 pathway. But C4 crops such as corn will have a harder time with C3 weeds. If your climate becomes warmer and drier, C4 weeds and crops will be favored over C3 weeds and crops. This effect may be stronger than the effect of increased CO2.

Silver Queen sweet corn with wilting pulled pigweed amaranth. Corn is a C4 crop, amarnath (pigweed) a C4 weed. Photo Kathryn Simmons

Other factors influencing growth include frost tolerance, drought tolerance, and the presence or absence of mycorrhizal fungi. The majority of flowering plants do form mycorrhizal associations, but many weeds and some crops do not. Brassicas, chenopods (spinach, beets, lambsquarters, amaranths), smartweeds and sedges do not. Mycorrhizae assist the growth of host plants by providing nutrients and a good growing environment. When conditions favor mycorrhizae, those crops are more competitive against non-mycorrhizal weeds.

The diameter of the roots also has a role. Large-seeded crops tend to have large diameter roots, while small plants tend to have small diameter roots, which can grow longer faster. Pigweed (small seeds) after 28 days of growth has a root-length:weight ratio eight times higher than sunflower (large seeds). Pigweed roots are better at gathering nutrients, because they explore more of the soil, and can absorb more nutrients (because the ratio of surface-area:volume is greater).

Some weeds flower near the end of their lifecycle, after growing quite large, in a “big bang” (pigweed and lambsquarters). Removing these weeds early in life prevents the competition from these large plants that reduce the crop yield. If you miss that opportunity, killing the weed later in life (before it seeds) will help future crops.  Other weeds are “dribblers” – they start to set seed while still small. They can hide among the crop plants, making seed whenever conditions are favorable. Failing to remove these weeds early in life will potentially reduce yields for many years. This is how galinsoga can be such a nuisance in vegetable farms, surviving where the soil is frequently cultivated, and sometimes neglected long enough for seeds to mature. It’s always worth hand-pulling a large galinsoga as you walk by, as the largest plants produce the most seeds.

Galinsoga – a fast growing, fast-seeding weed of cultivated soil.
Photo Wren Vile

All plant species have natural enemies (diseases and pests that have co-evolved to live in balance), plus the occasional alien plant enemy that could devastate the population. Consequently, there are few natural enemies of weeds other than imported ones. Bio-herbicides are rare. But there are less obvious natural enemies of weeds. The authors measured the mortality of lambsquarters and redroot pigweed in the absence of human intervention. 80% or more of the lambsquarters emerging after tillage died before maturity. Fungi and insects were the likely predators. Results with pigweed were similar.

There is a chart of edible weeds for those inclined to engage in direct weed eradication, and the chart includes cautions about toxic parts of each plant.

The chapter summary lists ten important lessons. Dealing with roots and rhizomes of perennial weeds; rotating between spring, summer and fall-planted crops; influencing when weed seeds germinate and when they die; using transplants; using slow release nutrients to feed your crops rather than the weeds; avoiding over-fertilization; preventing weeds from seeding; reducing arrival of new weeds on your farm.

Wheelhoe, Courtesy of Valley Oak

Chapter 3 is about cultural weed management. Ecological weed management involves “many little hammers”, using multiple strategies together in a complementary way. Crop rotation is one that involves advance planning. Spring weeds can be destroyed while preparing the soil for summer planting, reducing future pressures in spring crops. Good stands of overwintering cover crops, especially mixtures, can inhibit winter and spring weed germination. The diversity of field operations associated with particular crops is as important as the diversity of the crops themselves.

Growing healthy competitive crops is a fundamental part of weed management, and involves many aspects, starting with using high vigor, fast-germinating seeds. Planting the crop at an appropriately dense spacing will reduce weed opportunities. Any crop that produces multiple harvests (kale, tomatoes, squash) can be planted closer than most recommendations without loss of yield, whereas those with a single harvest (cabbage, lettuce, corn, root crops) will get smaller if planted too close. Planting 50% closer is usually worth trying, for a higher total yield, when smaller individual units are acceptable. Thus may involve more time harvesting, and bigger seed purchases. The reduction of weeds may benefit many subsequent crops.

Other factors not yet mentioned include row spacing, row orientation (plants get more light in rows that run N-S), choice of fast-growing or large-leaved varieties (Danvers are better at shading than Nantes type carrots), planting date (avoid the period when the dominant weed species is likely to grow vigorously), intercropping (practice with caution, avoid having two crops in competition), nutrient and water supply.

No-till cover crops, where the residue remains on the soil surface, will inhibit many weeds, and provide many other ecological benefits. Organic no-till isn’t the answer for every situation. It keeps soil cool and somewhat compacted, and doesn’t release its nutrients quickly, so it isn’t good for early spring crops, or early warmth-loving crops. To sow the necessary good stand of cover crops, tilling is required. This means no-till can have a valuable place in your rotation, but continuous organic no-till is not likely to work.

Tarping is a method of covering the soil with large opaque tarps for several weeks, to germinate and then kill emerging weeds by depriving them of light. This provides a seedbed ready to plant. Tarping can also be used to kill mowed cover crops or crop residues. Tarping can be useful in the transition from tilled to no-till farming, while weeds are still a big challenge.

Solarizing with clear plastic. Photo Pam Dawling

Solarization is another soil-covering practice, this time with clear plastic and the goal of heating the soil to kill weed seeds, pests and disease organisms in the top layer of soil. This method works in hot weather in areas with a good amount of sunlight. It works best when the plastic is laid tightly over well-prepared beds, providing good soil contact. The edges are buried to hold in the hot air. It takes several weeks to kill weed seeds, even when conditions are right.

A flock of chickens can do a good job of weed management, if penned in the vegetable garden early enough to allow 90 days after their removal before the crop is harvested (above ground crops) and 120 days for in-ground crops. These are commonsense food safety precautions required for Organic certification.

There are two main approaches to weed management. The first is to remove enough weeds so that crop yields are not compromised in an economically significant way. The second is to minimize weed seed production, aiming for very low weed populations, meaning little weed management work in the future. This preventive weed management requires more precise attention in the early years, including removing weeds that are not, in themselves, causing measurably lower yields. Either approach can be successful, but the preventive strategy is a good one for people who are growing older (!) and want less work in the future, while maintaining an income and satisfying work.

Chapter Four covers mechanical and other physical weed management methods. “The effect of tillage or cultivation on a weed population depends on the interaction between the nature of the soil disturbance and the ecological characteristics of the weed.” In other words, to control a particular weed, we need to know the features of that weed and choose methods of cultivation and tillage that will exploit the weaknesses of that weed, and take account of the weather, the soil conditions and the crop stage. Timing determines success, and the greatest success comes from using a planned sequence incorporating several operations.

There is a very clear explanation of vegetative reproduction of perennial weeds and how to thwart that process. Tilling chops up roots, which grow into new plants. Partial damage to perennial roots stimulates sprouting of dormant buds. The best chance of success comes from exhausting the root or rhizome pieces. With most perennial weeds, carbohydrates flow from the storage organ into the leaves until they produce enough food to return some to the root. The ideal stage to kill such plants is when the pieces of the storage organs drop to their minimum weight after growing new leaves. Generally this is after three or four leaves have grown.

Tilled fallow is a time without crops, when the plot is tilled often enough to stop weeds proliferating. Most annuals take 5 weeks to set seed, and so once every three weeks is a good tilling frequency, for management of both perennial and annual weeds. This will inevitably damage the soil structure. Growing a fast cover crop (buckwheat or a mustard) between tillages will reduce the damage.

Buckwheat cover crop in flower.
Photo Pam Dawling

A discussion of ten Principles of Mechanical Weeding follows. A useful chart of two dozen weeding implements and tools provides information on when and how they are best used, which crops they are most suited to and what their limitations are. The chart is followed by pages of clear drawings of various cultivators, with explanations of when they are most useful.

Often one goal is the creation of a surface layer of small aggregates allowing good air circulation and decreasing germination of new weeds. This is widely called a “dust mulch”. Weeding early, shallowly and often, is widely shared advice. Shallow soil disturbance can eliminate a large percentage of annual weeds, without bringing new seed to the surface. Small weeds do not re-root easily, as they have only small reserves of energy. Weeds over 2” (5cm) tall are more likely to re-root.

After the profiles of five farms with great weed management strategies, explaining their overall approach to weeds, comes the directory of weeds, including information on resources, naming, ecological information, recommendations for management and the limitations of those recommendations (for example, whether or not they have been field-tested).

There are summary tables of summer annual weeds, winter annual weeds, and perennial weeds, each subdivided into broadleaf weeds and grasses, with information on characteristics. To help with visualizing seed sizes from the weights given, they helpfully tell us that a lettuce seed is likely to weigh 1mg. The tables are followed by 3-4 page profiles for each weed, including several clear photos of the weed at different stages of growth, management suggestions, ecology and a handful of references for further reading.

There are tips on developing management plans for weed species that are not in the book. Some weeds are a big problem in a small geographical area, and of not much consequence elsewhere. Record your own observations, using the questions provided to focus your attention and identify the weed. Each taxonomic level (family, genus, species) can provide actionable information. There are some great resources for weed identification, leading me to find one from Virginia Tech https://weedid.cals.vt.edu/.

There is hope for dealing with even the worst weeds! “Competitive cover crops are effective for suppressing bermudagrass.” Example: A dense fall sowing of winter rye, barley or oats, harvested for forage in spring, with the stubble plowed under to allow sowing of a very competitive summer cover crop like cowpeas. The dense shade following the late spring soil disturbance will suppress the grass.

The directory is the main part of the book, and the part where you will want to search out your worst problems and form a plan. Keep this book in a place you can always find it when needed, for the rest of your farming life!

SARE logo

Time to sow fall broccoli and cabbage

Broccoli head after rain
Photo Wren Vile

We are almost at a big turning point of the growing season, the Summer Solstice, the longest day. We know that day-length influences plant growth, and that after the Solstice, some crops will gradually take longer and longer to reach maturity (others will bolt). Crops more influenced by temperature (like sweet corn) will continue to mature faster while the summer temperatures rise.

Here in central Virginia, most brassicas are planted in spring and again in fall. Unless your broccoli keeps going all summer, consider sowing a new crop for fall. Although it can be hard to think about sowing seeds in mid-summer, it’s very worthwhile to grow fall brassicas because as they mature in the cooler fall days they develop delicious flavor, while weeds and pests slow down. These crops need little care once established. The most challenging part is getting the seedlings growing well while the weather is hot. However, unlike some cool weather vegetables such as spinach and lettuce, brassica seeds actually germinate very well at high temperatures. The ideal is 77-85°F (25-29°C), but up to 95°F (35°C) works. Given enough water, summer seedlings will emerge in only 3 days. Once they have emerged, the challenge begins. As well as temperature and moisture in the right ranges, the seedlings need light (very plentiful in mid-summer!), nutrients, good airflow, and protection from bugs. We deal organically with flea beetles, Harlequin bugs, and sometimes cabbage worms. Our main defenses are farmscaping, and netting (and previously, rowcover).

My book Sustainable Market Farming, has a chapter devoted to Broccoli, Cabbage, Kale and Collards in Fall.

Fall broccoli patch.
Photo Kati Falger

Timing sowing of fall broccoli and cabbage

The number of days to harvest given in seed catalogs is usually that needed in spring – plants grow faster in warmer temperatures. To determine when to sow for fall plantings, start with your average first frost date (as an indicator of cooling temperatures), then subtract the number of days from seeding to transplant (21-28), the number of days from transplanting to harvest for that variety (given in the catalog description), the length of harvest period (we harvest broccoli for 35 days minimum), and another 14 days for the slowing rate of plant growth in fall compared to spring. For us, the average first frost is 10/14-10/20, and we sow 53-day broccoli 21+53+35+14 days before 10/14, which is 6/13-6/19.  The last date for sowing broccoli and cabbage is about 3 months before the first fall frost date. In our case that means July 14–20.

Planning and crop rotations for fall brassicas

Our rotation plan shows us a long way ahead how many row feet of fall broccoli and cabbage we can fit in. By the time we order our seeds in the New Year, we know roughly what we expect to grow. In February we draw up a spreadsheet of how much of what to sow when.

Because fall brassicas are transplanted in summer, it’s possible to grow another vegetable crop, or some good cover crops, earlier in the year. An over-wintered cover crop mix of winter rye and crimson clover or hairy vetch could be turned under at flowering, and be followed by a short-term warm weather cover such as buckwheat, soy or cowpeas. Brassicas are heavy nitrogen consumers. To minimize pests and diseases, don’t use brassica cover crops.

Systems for growing fall broccoli and cabbage transplants

The same systems you use for growing transplants in spring can also work well for fall. It can help to have your plants outside on benches, above the 3’ (1m) height of flea beetles. A shade-house might be ideal too. Direct sowing, in “stations” (groups of several seeds sown at the final crop spacing), works for small areas.

We use an outdoor nursery seedbed and bare root transplants, which suits us best. The nursery bed is near our daily work area, so we’ll pass by and water it. Having the seedlings directly in the soil “drought-proofs” them to some extent. They can form deep roots, and do not dry out so fast.

For the seedbeds we use ProtekNet on wire hoops. Choose the mesh size carefully. One with small holes is needed to keep flea beetles away – 25 gm or 47 gm. Overly thick rowcover can make the seedlings more likely to die of fungal diseases in hot weather – good airflow is vital.

Sowing fall broccoli and cabbage

Brassica seedlings growing outdoors under insect netting.
Photo Pam Dawling

 Our rough formula for all transplanted fall brassicas is to sow around a foot (30 cm) of seed row for every 12-15’ (3.6-4.6 m) of transplanted crop row. We aim for 3 seeds per inch (about 1 cm apart). This means sowing 36 seeds for 10 plants transplanted on 18” (46 cm) spacing. And we do that twice (72 seeds for 10 plants!), in two sowings a week apart, to ensure we have enough plants of the right size.

Fall Brassica Schedule

Our seedbeds have an 8-week program – see the spreadsheet above for examples of our timing, quantities and varieties. I like to have a regular afternoon every week to grow the transplants. If you’re growing for fewer than 100 people, you won’t need a whole afternoon! Each week after the first week, we also weed the previously sown plants, and thin to 1” (2.5 cm) apart. Then we check the germination, record it, and resow if needed to make up the numbers.

 

Bare root brassica transplants under Proteknet.
Photo by Bridget Aleshire

Transplanting fall broccoli and cabbage

We transplant most brassicas at 4 true leaves (3-4 weeks after sowing at this time of year). It is best to transplant crops at a younger age in hot weather than you would in spring, because larger plants can wilt from high transpiration losses. If we find ourselves transplanting older plants, we remove a couple of the older leaves to reduce these losses.

We transplant 6 days a week for an hour and a half or two hours in late afternoon or early evening, for 2-3 weeks. We water the soil in the plot an hour before starting to transplant. It is very important at this time of year to get adequate water to the plants undergoing the stress of being transplanted. Likewise, good transplanting technique is vital. Water a lot more than you do in spring. If you have drip irrigation, you can easily give a little water in the middle of each day too, which will help cool the roots.

One of our impact sprinkler tripods, in a broccoli patch.
Photo Pam Dawling

We transplant broccoli and cabbage in 34” (86 cm) or 36” (91 cm) rows, which is wider than necessary. Beds or paired rows can fit more plants in the same space, while still allowing room to walk. We hammer in stakes along the row, and attach ropes between them. These both mark the rows for transplanting, and support the netting that we use after transplanting to keep the bugs off. An 84” (2.1 m) width netting can form a square tunnel over two crop rows, giving good airflow. Wire hoops are an alternative. Watering the soil before planting, as well as afterwards, helps survival during the hot summer days.

Aftercare of fall brassicas

About a month after transplanting the broccoli and cabbage (late August-early September), we remove the netting, stakes, ropes and the sticks we use to hold down the netting edges, then hoe and till between the rows. Next we broadcast a mix of mammoth red clover, Ladino white clover and crimson clover. We use overhead sprinkler irrigation to get the clover germinated, and it also helps cool the brassicas. The ideal is to keep the soil surface damp for the few days it takes the clover to germinate. Usually watering every two days is enough. We may replace the netting if pest pressure seems bad.

 

Fall broccoli undersown with a mixed clover winter cover crop.
Photo Nina Gentle.

If all goes well, we keep the clover growing for the whole of the next year, mowing several times to control annual weeds. You could, instead, till in the clover in late spring or early summer to plant a food crop then.

Harvesting fall broccoli and cabbage

We harvest all our brassicas three times each week, and take the produce directly to our cooler.

Broccoli side shoots.
Photo Nina Gentle

Our main broccoli harvest period is 9/10-10/15, with smaller amounts being picked either side of those dates We like our broccoli heads to get as large as possible (without opening up) before we harvest. We test by pressing down on the head with our fingertips and spreading our fingers. We harvest as soon as the beads start to “spring” apart. This may be a little late for other growers. We also look at the individual beads and aim to harvest before the beads even think about opening. We cut the stem diagonally to reduce the chance of dew and rain puddling, which can cause rotting of the stem. Later we harvest the side shoots, until they are too small to bother with.

A storage cabbage, with curled-back leaf on the head, showing maturity.
Photo Bridget Aleshire

Cabbage heads up from 9/25 and holds in the field till late November. Cabbage is mature when the outer leaf on the head (not the outer plant leaves which are left in the field) is curling back on itself. For storage cabbage, we set the cut heads upside down on the stump, in the “basket” of outer leaves, and come back an hour later to gather them into net bags. This allows the cut stem to dry out and seal over, improving storability.

If you are already looking ahead to the fall, see my post Fall and Winter Vegetable Growing, Harvest and Storage, for lots of links to more info on season extension into cold weather; fall and winter vegetable harvests; and fall and winter vegetable storage. I will write more about other fall brassicas in the near future.

Big frosty fall cabbage.
photo Lori Katz

Fruit for the Month: June

Blueberries.
Photo Marilyn Rayne Squier

This is another post in my new monthly series, about small fruits that can be grown sustainably in a mid-Atlantic climate. I’ll talk about planting, pruning, harvesting and care of the plants, according to the season. I’ll give links to useful publications. I’ll have a focus fruit, and then more about others that need attention during the month. We do grow apples and pears, and some other tree fruit, but I’m not writing about those as I don’t have much recent experience.

Blueberries are the focus fruit for June

June is the month in our climate, to harvest blueberries. Blueberries are a great crop to grow, as they are not troubled by many pests or diseases (apart from birds). While you are harvesting take notes (or photos) of the various varieties you have, and when and how well they are producing, so that you will know which ones to propagate from in the winter, if you want more.

See my article about blueberries in Growing for Market magazine

See ATTRA Blueberries: Organic Production available free online, for a wealth of information from choosing varieties, planting, details on pests and diseases you might encounter. Updated 2022. Also search the ATTRA site for other info on blueberries, such as soil management (blueberries need acid soil), living clover mulches, and honeybees and alternative pollinators.

Harvesting blueberries

Blueberry harvest. Note “berry bucket” hanging around the worker’s neck. Photo Marilyn Rayne Squier

I recommend harvesting two days a week, in the mornings, once the dew has dried, to avoid spreading fungal diseases. Blueberries don’t deteriorate or over-ripen as quickly as softer fruit, so if you can only find time once a week, that will be OK. Or if you are selling blueberries, once a week may work better for your sales. Blueberries don’t crush as easily as strawberries or raspberries, so if you have lots you can put them in buckets or crates. We usually harvest into homemade berry buckets with long rope handles, that we can hang around our necks, freeing up both hands for picking berries. Our berry buckets are made by cutting plastic gallon jugs and adding rope through holes we punch near the top. Full berry buckets get emptied into a bigger bucket.

Only pick the berries that are purple-black all over. Check the back of each each ripe-looking blueberry to make sure it’s ripe all over. The area around the stem is the last to change color. Really ripe blueberries will “tickle” from the bush into your hand

Do not wash fruit before refrigerating, as this leads to rot.

Types of blueberries

We grow Northern Highbush blueberries here in winter-hardiness zone 7a (suitable for zones 3-7) and we like to have a crop we can harvest standing up!  There are also lowbush blueberries, which are popular in cooler climates, such as Maine. Rabbiteye varieties are better to the South, in the region roughly south of Interstate 40 (mostly zones 6-9). Rabbiteyes are taller plants, with smaller berries than highbush types. A new hybrid type, Southern highbush, is adapted to the southern rabbiteye zone and the coastal South (zones 6-10). Look into these if you are in the right area: they have a lower chilling-hours requirement, and flower and fruit earlier than highbush or rabbiteye varieties. As the climate changes, fruit growers are challenged by traditional crops no longer getting enough winter chilling hours to fruit. (Chilling is the number of accumulated hours at temperatures below 45°F/7°C in the dormant season.) Balance this with your changing frost dates, as earlier flowering will not be an advantage if your last frost is going to cancel the fruit. Remember that all blueberries are self-fertile but will produce better crops if you plant several compatible cross-pollinating varieties.

Young Blue Crop northern highbush blueberry.
Photo Kathryn Simmons

At our farm, Duke has been a very reliable early fruiting highbush variety, whereas Spartan has not worked out. We like to have several varieties with different ripening dates, to extend the harvest. Blue Crop, Blue Jay, Elliott and Chandler also do well here. If I was starting over, I’d also try some Southern Highbush varieties.

We have bought good plants from Finch Blueberry Nursery in Bailey, North Carolina, as well as from a more local source in SW Virginia (now retired). If you only want a few plants, buy potted blueberry plants locally. Otherwise, order bareroot plants shipped to you. In Virginia Edible Landscaping offers a wide choice.

When to plant blueberries

If you are planning to plant blueberries, here are some considerations. Generally you will want o buy young bushes and plant them in the dormant season. In warm areas, plant in late fall so the plants get roots established before your early spring thrusts them into opening buds. In cooler zones, plant in early spring, so that winter does not kill them.

New blueberry plant with winter wire mesh protection. Photo Kathryn Simmons

As with all perennials, clear the area of perennial weeds the previous year, and reduce annual weeds, for instance by growing a good cover crop, which will smother emerging annual weeds and also feed the soil. Get a soil test, and follow the recommendations to amend the pH to 4.8-5.5 using sulfur in spring or fall before planting. I like the pelleted sulfur, that looks like lentils, because it is easy to spread, and no dust gets in your lungs. Depending on your soil type, you might need 430-1750 pounds of S per acre, or 1-4 pounds per 100 sq ft. Work in some good compost before planting.

Plan space between the rows that will let you walk, mow or whatever you need to do even once the bushes have reached full size. 8-12ft is recommended. Ours are a bit closer than that. In the row you can either plan for a hedge effect, or leave yourself access space. You can plant blueberries on raised beds or wide ridges. You can move bushes later in life, if you find they are competing too much.

Blueberries six years after planting. Photo Kathryn Simmons

Plan how you will cover the soil. I recommend landscape fabric topped by bark mulch or woodchips. This combination works well to keep perennial weeds at bay (wiregrass!). If you are avoiding plastic, you can use double layers of overlapping cardboard topped by 3” of organic mulch: chips, sawdust, straw or spoiled hay. Blueberries don’t do well with plastic mulch that is impervious to water, as it encourages the roots to grow just under the plastic, where they can easily get overheated and die. Some people like to grow a living mulch, perhaps mowing it to mulch closer around the plants once it dries. A hybrid model has mulch in the rows and a cover crop between the rows.

Blueberries have shallow roots, so you will likely need some irrigation method. I like drip irrigation, but overhead sprinklers work too.

You will, of course, have some annual care to provide. Each spring, expect to provide some source of nitrogen and potassium, as needed.  I’ll cover that another time. Each winter, prune for strong branches and good levels of production, and remove any perennial weeds.

Blueberries showing Tenax fencing and basket balls on posts to support roof netting. Photo Kathryn Simmons

Pests to watch out for include big ones like deer, groundhogs, birds and uninvited humans. We have a triple fence, with wire netting in the ground against burrowing animals, 7’ tall Tenax deer fencing, and seasonally, Avigard flexible bird netting over the top. For our newer blueberry planting we make a temporary hooped structure and cover just with the bird netting, held down to the ground with 6” soil staples. This planting is nearer our buildings than the older one, and is not visited by deer or groundhogs.

Blueberry netting on PVC electrical conduit hoops. Photo Pam Dawling

Smaller pests include blueberry maggots, blueberry stem borers, cranberry fruitworms, cherry fruitworms, Japanese beetles, leafrollers, leafhoppers, and aphids. Our perhaps, like us, you will not be troubled by any of these.

Diseases include mummy berry, Botrytis grey mold, Anthracnose, stem blight, stem canker, rust, phytopthora root rot, Phomopsis twig blight, blueberry stunt and several viruses. A Cornell University blueberry diagnostic tool offers a step-by-step exercise to help figure out what diseases may be affecting your crop.

Propagate blueberries by layering a low branch, as you see here with Chandler variety. Photo Kathryn Simmons

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Other small fruits available in June

Two rows of floricane raspberries with a willow and grapes in the background. Photo Kathryn Simmons

Cherries, red raspberries, strawberries, Juneberries, gooseberries  mulberries. Blackberries, apricots, peaches, plums.

If you live in Virginia or nearby, see this produce calendar

Other fruit care in June

New grape vine in May. Photo Bridget Aleshire

Grapes: Mow, weed, water in drought. If you have young vines, remove side branches from the trunks, and fruitlets. Your goal is to first grow strong plants, then produce grapes after that.

Strawberries: Prepare for new strawberries in early June: Disk or till the area for new strawberries if using bare-root plants, and prepare the beds with compost, driptape, and landscape fabric.

June 16-July 16: If using bare-root transplants, plant new strawberry beds.

Late June/early July (after fruiting): Dismantle two-year-old beds. Renovate carry-over strawberries by mowing or shearing/clipping weed and mulch, but don’t compost them. . Plant new strawberries if using bare-root transplants, perhaps rooted runners in the paths of older beds.

Rainbow and Kathryn spread hay over the new strawberry bed. Photo Luke Stovall

All fruit: Water all fruit crops. Weed, mow aisles as needed. Weed and mulch rhubarb, lop flowers. Record condition and fruiting dates of new grapes, blueberries. Note best varieties.

Speaking Events September 2022-April 2023

 

Signing books at a winter conference.
Photo P J Kingfisher

I started to make in-person bookings again a year ago, then Omicron arrived and lots of conferences switched to being virtual. The only in-person event I attended this spring was the PASA conference, which I enjoyed a lot. I am still doing some virtual events, and planning some live ones too. Everything is subject to change!

As of right now I have two in-person events booked, and one new podcast interview. June and July are the months for speakers to apply to make winter and spring conference presentations, so I’ll be doing that! See my Events Tab for ideas I have of which events to apply to.

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Center for Arkansas Farms and Food logo

September 2022 Event

Center for Arkansas Farms and Food

https://farmandfoodsystem.uada.edu/

Sunday September 18, 2022, 1-4.30 pm

High Tunnel Season Extension (Cool Season)

View through the hoophouse doors in December.
Photo Kathleen Slattery

Contact 479-575-2798 or [email protected]

CAFF Beginning Farmer/Apprenticeship Farm Tours and Workshops

Workshop: In-person. CAFF Farm, 1005 Meade Ave, Fayetteville

CAFF was developed to strengthen and expand our food and farming system, enhance local communities, and provide opportunities for farmers, food entrepreneurs and food system leaders.

Combining traditional and experiential learning opportunities, their Farm School and Apprenticeship programs teach the production and business skills to develop resilient and sustainable businesses.

CAFF is dedicated to increasing the number of thriving farms and farmers in Arkansas. To accomplish this, the center provides farm education, training, networking, and resources. Creating a supportive farm community network will bring more people into farming and help retain current farmers by increasing their success.

Join CAFF at the farm to learn about extending your growing season with high tunnels. Space for this class is limited.

The CAFF Jan. 11 to March 1 two-hour courses remain available for viewing through Oct. 31. To pay the $10 access fee, please visit the registration page and email Heather Friedrich, program manager, at [email protected] to confirm receipt.


March 2023 Event

John C Campbell Folk School 

https://www.folkschool.org/index.php www.folkschool.org

March 26-April 1 2023

One Folk School Road, Brasstown, NC 28902

A week-long course:

Growing Vegetables Year Round

A harvest cart with cabbage, kale, squash and lettuce.
Photo by Wren Vile

Make the most of your space and time growing vegetables at home using planting schedules and techniques timed to the seasons, seed varieties, crop rotation, and use of protective structures such as coldframes and greenhouses. Learn labor saving and innovative planting and soil fertility techniques for growing and harvesting a full range of fresh, delicious, organic vegetables. Fill your salad bowl and dinner plate year round!

Folk School logo

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Accidental Gods Podcast

Exploring the liminal space between science and spirituality, philosophy and politics, art, creativity – working towards the conscious evolution of humanity.

Accidental Gods is two women, Manda Scott and Faith Tilleray, dreaming of a different future. Faith Tilleray designs the website and the Instagram feed. Manda Scott is a podcaster (also: novelist, smallholder, renegade economist etc. etc. ). Both are living in the UK.

Accidental Gods Blog

Recent posts include Imagination Activism, Bioregionalism, Sacred Earth Activism, managing the New Economy (based on SEEDS regenerative currency), and Making Use of Methane.

Which Vegetables are Genetically Modified (GMOs)?

Our first sweet corn of the season. Bodacious. Early July. Not GMO
Photo Pam Dawling

Recently we were given a gift of sweet corn from somewhere warmer than central Virginia. It wasn’t Organic, so I wondered if it was genetically modified. I try to avoid eating GMOs, because I don’t support the practice of inserting bits of other organisms in existing crops. Corn varieties often have Bacillus thuriengensis (Bt) inserted in their DNA with the goal of killing caterpillars that eat corn kernels.

USDA Organic symbol

Anything certified USDA Organic is not allowed to have any GMOs in it, so that’s one way to avoid getting GMOs. Growing your own food is a certain way to avoid GMOs, if you don’t buy GMO varieties or suffer cross-pollination from GMO crops.

Non-GMO Project symbol

The Non-GMO Project is the U.S. organization that provides testing and labeling for absence or presence of GMO in products. The “Non-GMO Project Seal” certifies that the product contains 0.9% or less GMO ingredients.

I’m going to skip ahead to talking about which vegetable crops are available in genetically modified varieties, because there are not many, and I’m not interested in worrying people! Then I’ll go into details.

The Big Three GMO Crops in the US

Edamame soy beans (soy for fresh eating). Not GMO.
Photo Raddysh Acorn

Soy, canola and corn are the three food crops in the US that are most likely to be genetically modified. Starting with corn (maize): 92% of all corn grown in the US is GMO. Of corn grown, only 1% is sweet corn. Of sweet corn grown in 2018, 10% is GMO. When you see a field of corn, it is almost certainly GMO, unless you are looking at an Organic farm.

What is field corn? “Corn (such as dent corn or flint corn) with starchy kernels that are used especially as livestock feed or processed into food products (such as cornmeal, corn oil, and corn syrup) or ethanol,” (Merriam Webster). Of the field corn in the US, 40% goes to make ethanol for vehicle fuels, 40% goes to livestock feed, and 20% goes into processed foods for humans.

In 2000, GM StarLink corn was recalled, when over 300 different food products were found to contain a genetically modified corn that had not been approved for human consumption (only animal feed). It was the first recall of a genetically modified food.

What about wheat? Farmers have shown a distinct preference for not growing GMO wheat. This is because much of the wheat grown in the US is for export, and people in many other countries refuse to eat GMOs.

Which Other Vegetables Might be GM?

Here is a 2013 article published in the Journal of Food Science and Technology. “Genetically modified foods: safety, risks and public concerns—a review” by A. S. Bawa and K. R. Anilakumar

There are only a few vegetables that have any GMO varieties. Some have been tried and failed. All vegetable seed is non-GMO unless labeled, and when purchasing GMO seed, you have to sign waivers. When searching on line, try various labels: genetically modified, GM, genetically engineered, GE, transgenic.

Gentry yellow squash in our hoophouse in late May. Not GMO
Photo Pam Dawling

Summer Squash and Zucchini

To avoid zucchini yellow mosaic virus and watermelon mottle virus in summer squash and zucchini, GM varieties were created, starting in 1995. When I researched GM squash varieties in July 2017 for an article I wrote, I found mention of ten summer squash and zucchini, but now there seem to be fewer. On the Bayer/Seminis website for their squash varieties, in 2017, these all helpfully had a “B” icon (Biotech). The names sound like B-movies: Conqueror III, Destiny III, Liberator III, Patriot II, Prelude II, XPT1832 III yellow squash and Judgement III, Justice III, SV0474YG, SV6009YG zucchini. The website has been updated, as have the variety offerings, and they are less prominently labeled. ZW-20 virus-resistant yellow crookneck squash is a current transgenic line.

In 2005, about 13% of the zucchini grown in the USA was genetically modified to resist three viruses; the zucchini is also grown in Canada (Johnson 2008).

Mexican researchers in 2004 wrote a paper Assessing the risk of releasing transgenic Cucurbita spp. in Mexico. Localities with native wild relatives of transgenic squash were at risk of the greatest trouble from cross pollination. The genetic legacy of ancient squash lineages was at risk. Gene flow between crops and their wild relatives was widely documented. The authors urged much caution about where and when GMO squash should be permitted.

GM squash also poses a risk that its virus genes or the proteins they produce could interact with other viruses to produce new diseases. And, as with any genetically engineered crop, the squash poses the risk that its new genes might cause it to spread and become difficult to control.

Sugar Beets

The USA extracts 90 % of its sugar “needs” from US-grown sugar beet and sugarcane. Of the domestically grown sugar, half comes from sugar beet, and half from sugarcane. After deregulation in 2005, sugar beet resistant to glyphosate (RoundUp) was extensively adopted in the USA. 95% of sugar beets grown in the US are GM. The sugar produced from GM sugar beets is highly refined and contains no DNA or protein—it is just sucrose. In 2008, the Animal and Plant Health Inspection Service (APHIS), a division of the USDA, performed a court-ordered environmental review of the modified seed and announced that there was no risk to other crops such as beets (beetroot) for fresh eating and pickling, or related crops such as Swiss chard.

Hawaiian Papayas

Since 2010, at least 80% of papayas grown in Hawaii are GM, to get around the devastating problem of papaya ringspot virus.

 

Jubilee tomato in our hoophouse in early June. Not GMO
Photo Pam Dawling

The ‘Flavr Savr’ Tomato

Consumers in the northern regions of the U.S. rely on tomatoes shipped in from the South if they want fresh tomatoes beyond the summer. To survive shipping, tomatoes are picked at the “mature-green” stage. They have already absorbed all the vitamins and nutrients from the plant that they can, but have not started to ripen. To ripen the green tomatoes, they spend 3 to 4 days in rooms where ethylene gas is released, and are then shipped at temperatures not lower than 50 degrees, to preserve what flavor they have.  These tomatoes are probably still a few days away from being ripe.

Calgene, a biotechnology company, developed a tomato with a gene that slows the softening process that happens with ripening. Pectin gives tomatoes their firmness. The pectin in ripening tomatoes becomes naturally degraded by an enzyme and the fruits soften, making them difficult to ship.

The scientists “reversed” the tomato softening gene and reintroduced it into the plants. Reducing that enzyme in tomatoes slows cell wall breakdown and keeps the fruit firmer for longer. In order to tell if their “Flavr Savr” gene was successfully inside the plants, scientists attached a gene that makes plants resistant to the antibiotic kanamycin. By exposing the plants to kanamycin, they could tell which plants had accepted the Flavr Savr gene. Once in a tomato plant, the Flavr Savr gene attaches itself to the gene activating the softening enzyme. When the Flavr Savr gene is there, the “softening” gene cannot give the necessary signals to produce the enzyme that destroys pectin.

Production of the Flavr Savr stopped in 1997. Production costs were too high, and consumers did not find a benefit. See Whatever Happened to the Flavr Savr Genetically-Engineered Tomato

A ladybug on a potato leaf, looking for pests to eat. Ladybug larvae eat eggs such as Colorado Potato Beetle eggs. Not GMO
Photo Kathryn Simmons

NewLeaf (and other GM) Potatoes

 The NewLeaf GM potato was brought to market by Monsanto in the late 1990s. It was developed incorporating Bacillus thuringiensis (Bt) bacteria to kill Colorado potato beetles. The target audience of fast food retailers rejected it and food processors ran into export problems. It was withdrawn from the market in 2001.

In 1998, a safety study (Ewen and Pusztai 1999) of GM potatoes with incorporated snowdrop bulb lectin (GNA) gene (Lectin acts as an insecticide), showed significant changes in the intestines of rats fed GM potatoes. The tested potatoes were not a commercial variety and not intended for human consumption, but the public were alarmed.

In 2010 Amflora was developed by BASF Plant Science for production of pure amylopectin starch for manufacturing waxy potato starch. It was approved for industrial use in the European Union in 2010, but was withdrawn in January 2012 due to rejection by farmers and consumers.

In 2011, BASF requested approval for its Fortuna potato as feed and food. The potato was made resistant to late blight by adding resistant genes that originate in the Mexican wild potato Solanum bulbocastanum. In February 2013, BASF withdrew its application.

In 2014, the USDA approved a GM potato type, Innate, developed by the J. R. Simplot Company that contained 10 genetic modifications that prevent bruising and produce less (carcinogenic) acrylamide when fried. The modification uses RNA interference (deactivating genes already present), rather than introducing genetic material from other plants or animals. Ranger Russet, Russet Burbank, and Atlantic potatoes are examples of varieties using this technology. McDonald’s announced that they have ruled out using Innate.

In 2017 scientists in Bangladesh developed a GM variety of potato resistant to late blight.

Arctic Apples

In February 2015 Arctic Apples became the first GM apple approved for sale in the US. RNA interference is used to reduce the activity of polyphenol oxidase, preventing the fruit from browning.

Mushrooms

In April 2016, a white button mushroom (Agaricus bisporus), genetically modified using the CRISPR technique, received the go-ahead, as the USDA considers it exempt because the editing process did not involve the introduction of foreign DNA, just deletion from a gene coding for an enzyme that causes browning, reducing the level of that enzyme by 30%.

 The Problems with GMOs

When GM varieties are planted on a commercial scale, resistant weeds and pests can evolve. The emergence of resistant insects can negate the effects of a Bt GMO. Also, if herbicide spraying becomes more frequent on herbicide-tolerant GMO varieties, weeds can develop resistance to the herbicide. This can cause an increase in herbicide use or an increase in the amount and types of herbicides used on crop plants. It is not a coincidence that herbicide producers are behind this research.

Further investigation is needed to learn if residues from herbicide- or pest-resistant plants could harm soil organisms. Another uncertainty is whether the pest-resistance of GE crops can cross to related weeds, creating resistant weeds. Possibly insect-resistant plants can cause increased death rates to one specific pest, decreasing competition and allowing previously minor pests to become a major problem. Also, it could cause the pests to move to another plant that had been unthreatened. A study of Bt crops showed that beneficial insects are also exposed to harmful quantities of Bt. It is possible for the effects to reach further up the food chain to affect crops and animals eaten by humans.

It is possible that virus-resistance can lead to new viruses and new diseases emerging. Naturally occurring viruses can recombine with viral fragments, forming new viruses.

The main concerns about adverse effects of GM foods on human health are the transfer of antibiotic resistance, toxicity and abnormal immune responses. A known allergen may transfer from a GM crop into a non-allergenic crop and create a new allergen. Patients allergic to Brazil nuts and not to soybeans showed an allergic response towards GM soybeans.

  A Law on our Side

In January 2022 the National Bioengineered Food Disclosure Standard became mandatory. The new Standard requires food manufacturers, importers, and other entities that label foods for retail sale to disclose information about BE food and BE food ingredients. This rule is intended to provide a uniform national standard for providing information to consumers about the BE status of foods. The Final Rule was published in December 2018

 

Bioengineered Food symbol

The BE Food Disclosure must be placed on either the main information panel on the label, or an alternate panel “likely to be seen by a consumer under ordinary shopping conditions.” For bulk foods, retailers are responsible for displaying the BE food disclosure on or near the bulk item. Now you know what to look for!

Book Review: Grow More Food by Colin McCrate and Brad Halm

Cover of Grow More Food, by Colin McCrate and Brad Halm

Book Review: Grow More Food, a Vegetable Gardener’s Guide to Getting the Biggest Harvest Possible from a Space of Any Size, by Colin McCrate and Brad Halm. Storey Publishing, 2022, 300 pages, diagrams, $24.95

This book, Grow More Food, is an updated version of the authors’ 2015 book, High Yield Vegetable Gardening. I have been a big fan of that book since it was published. This book has much the same content but is a larger format with color photos and a larger print size.

Some of the content has been rearranged into a different, more logical, order, (athough a good index does make all topics findable). Some of the more technical or professional terms have been changed from the earlier book. “High yield” has become “productive”. The real or fictional example gardeners have almost disappeared, although drawings of their gardens live on.

If you have High Yield Vegetable Gardening and like it a lot, as I do, you probably don’t need to buy Grow More Food, unless as a gift for a friend, or if you are going to relegate the old version to the greenhouse or shed as a quick reference work. You may like to have the bigger print and the more informative and inspiring color photos in your house for periods of longer contemplation and planning. The new one, however, does not have the lay-flat spiral binding of the old one. The book is definitely a good one to keep on hand, in one version or the other.

The authors founded Seattle Urban Farm Company in 2007, and have been running it since, helping more people grow food. Their focus is to ‘find joy in the simple pleasure of doing a little better each season.” Here they are bringing proven professional techniques for bigger harvests to vegetable gardeners on any scale. The information is presented very clearly, without jargon, so that home gardeners will easily benefit. As I said in my review of High Yield Vegetable Gardening, this also provides newbie professional growers with solid information on techniques that work, without the need to understand everything at once.

These are gardeners after my own heart. Here are details you will benefit from knowing and putting into practice, which are not found in many gardening books: interpreting and using soil tests, choosing onion varieties that work at your latitude, succession planting for continuous harvests, flame-weeding, making soil block mix of the right consistency, dealing with salt build-up in greenhouse soils, minimizing nitrate accumulation in winter greens under cover. There are lots of useful charts.

This edition has more emphasis on building and maintaining good soil, and includes sidebars that dig deep into particular topics such as providing onion flavors all year, making space dedicated to perennial vegetables, converting farm-scale soil amendment rates to garden-scale ones, setting transplants at different depths, hand pollination of cucurbits, and the role of ethylene in crop storage.

Dibbling holes for planting leeks.
Photo Wren Vile

The sequence of topics starts with clarifying your garden priorities, planning and record keeping: “It’s no exaggeration to say that a detailed garden plan alone can double or triple the productivity of a garden.” There’s help in choosing the right size of garden for your needs, experience and available time. Next, create a map or drawing of the garden site, including buildings, paving and trees, and consider which crops to grow. The chart of annual crops includes days to harvest and whether to direct sow or transplant. This enables gardeners to compare short-season crops, long-season crops and those in between, to plan food for the whole season; and sequential follow-on crops to make best use of all your space.

Once you’ve figured which crops to grow, how much of each to plant, when (and how often) to plant them, you can create your planting calendar. There are options for format, and a real-life example with arugula. This is followed with a sample section of a planting calendar with harvest tracker and room for notes for next year.

The next big question is “Where?” Make a map of your garden and think about a crop rotation to help you get the best yields by avoiding planting the same crop in the same place each year. A two-year rotation simply has two groups of crops and two beds or plots that flip each year. A three-year rotation can consider which crops need heavy feeding and follow two years of heavy feeders with one of light feeders. Also, if you don’t have soil-borne diseases, consider the counter-intuitive idea of following brassicas with brassicas in the spring and fall of a year, and avoiding brassicas in that bed for the next two or three years. For gardeners like me who grow a lot of brassicas, this makes planning a rotation easier. As well as an overall map of the whole garden, make a planting schedule for each bed, with space to write things down.

A pest and disease management log is another useful piece of record-keeping. It will remind you when to be on the lookout for particular problems, and what strategies worked for you previously. A garden log or diary with entries each day you garden can end with a To-Do list, including things to buy, and watch for.

Colorado potato beetle on an eggplant leaf.
Photo Pam Dawling

And that’s just the first part of five. The second is about building healthy soil, providing a diverse ecosystem, high nutrient-level crops and big harvests. There’s information on making boxed beds, if you want to go in that direction, or lasagna beds, where organic materials are piled in layers, and tilled beds incorporating amendments. Tarping (covering soil with tarps to smother weeds) is also discussed. Mulches for pathways are compared. There is a very clear description of taking, submitting and understanding results from soil tests, accompanied by an annotated soil report.

There are clear instructions on making quality compost, buying compost, improving soil with cover crops, and mulching over winter. This chapter includes a manageable chart of “beginner” cover crops (buckwheat, four clovers, peas, vetch, mustard, oats and winter rye). Then comes the weed-reduction chapter. Strategies include dealing with weeds while they are small and seed-free, hoeing (photos of various types, with pros and cons), flaming (good safety tips here!), tarping and mulch.

Part 3 is Get to Know Your Plants – “Grow More Food by Planting the Right Varieties at the Right Time with the Best Care.” Smart gardening, with no wasted effort. Choose suitable varieties (open pollinated ones and hybrids) to match your climate and your goals. Order sensible quantities, store leftovers carefully (cool, dry, dark, airtight, mouse-proof) for use next year. There’s a two-page chart of Seed Lifespan, including parsnips and peanuts, something for every climate. Seed treatments to improve yields are covered, including soaking, scarification and inoculation.

The chapter on transplanting and direct seeding advises on which technique works for which crops. There’s information about supporting plants, from hilling up with soil, to making trellises. Supplemental fertilizers (during the growing season) are useful for some crops, not needed for others (the lists are in the book). The general theme is that heavy feeders and fast-growing crops will benefit. There’s an interesting section on pruning for production, including for good air circulation; for delaying bolting; for encouraging earlier harvests (by root pruning); and removing late flowers to focus energy on maturing fruits already formed.

The goal of managing pests and diseases is not to eliminate them all, but to control levels by cooperating with and stimulating natural processes that restore balance. This process starts with preventing problems, and ramps up if this does not succeed well enough. Develop good soil; attract beneficial insects; use rowcover or netting to keep expected insect pests from vulnerable crops; use deterrent sprays such a baking soda, hot pepper, garlic, kaolin clay for various problems; bring in beneficial organisms.

To nip any problems in the bud, it is important to monitor or scout your gardens at least once a week, looking for problems. Distinguish problems caused by extreme temperatures and water shortage from those caused by pests and diseases. Find good ID resources. You may be able to hand pick or trap enough pests to make the difference between a damaging outbreak and a trivial level. The authors explain why it is unwise to rush for the sprayer. Sprays are a last resort, even organic ones, because they may kill unintended insects, and they leave some of the pests alive to develop resistance, making that spray ineffective in the long run. There’s a two-page chart for pest and disease management strategies.

Part 4 is entitled Create Efficient Systems. It describes how to use your resources well, so time, money and space are not wasted, and you get the best from your efforts. Set up a home nursery to grow your own transplants, and plant the varieties you want in the quantities you want, to fit your schedule. Here are details on light intensity and where on the color spectrum the light should fall. You may be surprised just how much light plants need. For overall plant growth, general full-spectrum lights are just fine for a nursery, where the plants are headed outdoors to the natural source. Growing plants to maturity indoors is another (costly) matter.

The photos on making soil blocks are very helpful, and it’s a topic not covered in many places. Various types of plant container are covered. Making your own seed-starting schedule is explained. There’s info on propagating from cuttings, grafting with silicone clips, and watering or misting tiny plants. The next chapter covers irrigation of more kinds: drip systems (good description and photos for newbies) and sprinklers (including oscillating lawn-type sprinklers, wobblers, impact sprinklers and microsprinklers). This section will clear up a lot of confusion. Whichever you choose, make yourself an irrigation map, helping ensure you run pipelines and hoses along the best route, and set up sensible zones. Designs that minimize the need to move equipment around during the growing season will preserve your sanity and sense of well-being.

One of our im[act sprinkler tripods, in a broccoli patch.
Photo Pam Dawling
Part 5 is Extend and Expand the Harvest. This includes storage. Good techniques and timely harvesting let you get the most food from your crops, and eat them at peak quality and flavor. Extending the growing season includes starting as early as possible, finishing as late as possible, helping crops get through hot weather as well as cold, and planting successions to give you a seamless harvest through the growing season. Try crops you have not grown before.

The section on choosing protective structures will help you think about the pros and cons, costs and benefits of low tunnels (with rowcover or clear plastic), cold frames, greenhouses, high tunnels (also called hoophouses), and combinations of low tunnels inside high tunnels. If you are undecided on this topic, Grow More Food could save you from buying the wrong thing and wasting many times its cover price. And it could save you the big disappointment of not getting the harvests you hoped for. Consider not just cost but also ease of use (let’s enjoy our gardening!), suitability for your climate, and gained productivity. Glass greenhouses and greenhouse heating are often not cost-effective, and heating brings environmental costs too.

When weighing up design features, do the math for your own situation. I dislike the “comb” greenhouse bed design because it doesn’t work so well with drip tape. The authors say it maximizes usable space. But the difference is very small and the disadvantages are several. You lose the staging area of the lengthwise beds design. Many gardening books neglect methods of summer cooling, but the climate emergency is upon us. Here you will find good ideas about shade cloth and using overhead irrigation for cooling.

The next chapter is about timely harvesting and successful storage. Remember when planning your garden to think about how much food you can use, including not just how much your household can eat, but also how much time you have each week for harvesting and storage. There is a good discussion about becoming a skilled harvester. For each likely crop there is a short description of which part to harvest, and how to recognize maturity.

Next is a section on harvesting “hidden” crops – extra harvests form your garden: weeds, less usual parts of crop plants, such as flowers, garlic scapes, carrot leaves, pea shoots and tendrils, and sweet potato leaves. You can harvest more food from the same plants by choosing varieties that provide multiple harvests (loose leaf crops, broccoli side shoots, turnip and beet greens and roots).

How to harvest garlic scapes.
Photo Wren Vile

There’s a bit on washing crops, and food safety. Then harvesting for maximum freshness and quality, and storage, short and long term. Not everything should be refrigerated! Onions, garlic, winter squash, potatoes and sweet potatoes need to be cured before long-term storage. Be sure to get the details right, or you could have big losses. There is a 4-page chart of storage conditions for various crops. Although I agree with the authors on almost everything they write, I wouldn’t wipe down winter squash with bleach. I’ve never found it necessary.

At the end of the book are worksheets you can photocopy and use. Or you can download them from Seattle Urban Farm. They include a Crop Amount Worksheet, Planting Calendar Worksheet, Planting Dates Worksheet, and Garden Planning Chart. The website also has sample log pages for a specific bed, for the garden as a whole, a pest and disease management log, harvest log, and planting calendar with harvest tracking.

There is a resource section and I was particularly happy to find two resources for non-toxic wood preservatives for garden use. The index looks very thorough – 21 columns for 300 pages.

The Seattle Urban Farm Company has a blog and a podcast, and their Projects page will give you lots of ideas on garden layout and design. Their shop sells training sessions, webinars, and individual coaching.

Brad Halm
Colin McCrate

Okra Planting Time

Young okra plants.
Photo Wren Vile

We’ve reached mid-May, the time of year to transplant our okra. Okra is a tropical annual in the mallow family, and is widely adapted where the frost-free season is long enough. Okra is heat- and drought-tolerant and has few serious pests or diseases. Those in hot climates will need to deal with its exuberant growth in mid-summer. Those in cold climates should choose fast-maturing varieties and transplant into black plastic. In areas with cold nights, okra can only be grown in a hoophouse.

Okra Varieties

We like Cow Horn okra from Southern Exposure Seed Exchange, which gives good yields and sturdy plants in our zone 7a climate. It is one of a few varieties that can grow relatively large pods without their becoming tough. We are sometimes not good at finding all the pods when harvesting, so it is an advantage to us if they are still good to eat when bigger than normal. SESE has an Okra Growing Guide.

High-yielding varieties include Cow Horn (55 days), Jade (55 days), Cajun Jewel (50 days).

Spineless (easy to harvest) varieties include Clemson Spineless (56 days), and Evertender (50 days). Red-podded varieties include Burmese (58 days), a high-yielding dwarf heirloom, and Red Burgundy (49 days), reported to do well in “cooler” areas, although it will not do much until day time temperatures reach 80°F (27°C).

Close up of Cow Horn okra pods.
Photo Kathryn Simmons

Crop Requirements and Yield

Okra does best in well-drained, fertile, loamy soils with high organic matter. Wet clay soils can drown the plants. It grows best with a pH between 6.5 and 7.0, although as high as 7.6 is still OK.

5 gm sows 50’ (15 m) at 6” (15 cm) spacing. Average yields are about 50-100 lb/100’ (7.6-15 kg/10 m). We grow 90’ (27 m) for 100 people, which provides enough for some pickling too.      

Sowing okra

According to Rodale’s 600 Answers, germination speed can be improved by freezing the seed overnight, then soaking in hot water for ½-1 hour before sowing. It needs to be warm enough to get your seed germinated: you can soak the seed for 8 hours in water at 88°F (31°C).

When we direct sow, we “station-sow” – we put three seeds ½-1” (1-2.5 cm) deep at each spot where we want a plant to grow. We do this on May 1, with rowcover, as this is around our last frost date, and we want to avoid disasters! Direct sow once the soil temperature averages 65°F (20°C), 3-4 weeks after last frost.

When seedlings have 3-4 leaves, we thin to the strongest seedling. Okra is sturdier if direct sown, rather than transplanted, but you work with the climate you’ve got!

Transplanting okra

Okra seedlings in a Winstrip 50-cell tray.
Photo Pam Dawling

Usually we transplant, especially if we are intercropping. For transplants we sow April 15, using soil blocks or Winstrip 50-cell flats. I was amazed to learn that at 6″ (15 cm) tall, plants could have taproots three times as long! At full maturity, the tap root could be 4½ ft (1.4 m).  To avoid stunting the taproot, get the small plants in the ground as soon as you can, carefully.

We transplant 3-4 week old starts – a plant with 3 or 4 leaves is ideal – at 18” (45 cm) spacing in a single row down the middle of a bed. We transplant May 11, 10 days later than the direct-sowing date. In the past we used wider in-row spacing, but found we could get a higher yield with the “hedge-like” closer spacing.

Some growers plant as close as 6” (15 cm) in the row, with 5’ (1.5m) between rows, or plant double rows with 12” (30 cm) between plants, and wider spacing between the beds. Thick planting requires very fertile soil, and risks diseases from poor air circulation. Wide spacing can lead to heavily branched plants, and more pods per plant, but not necessarily more pods for a given area. It may lead to a later start to the harvest, as flowering is delayed while the plant grows bigger.

Burmese okra flower.
Photo by Raddysh Acorn

Intercropping Okra

Okra is slow-growing until hot weather arrives. We sometimes take advantage of this and its upright growth habit to transplant okra into a bed of early cabbage. We transplant cabbage in two rows along a 4’ (1.2 m) bed on March 10 and the okra in a single row down the middle on May 11. We mulch the cabbage, which has the disadvantage for the okra, of cooling the soil, so don’t try this if direct sowing! At first the cabbages are relatively small, and the okra uses the open space in the middle of the bed. As the plants grow, we remove outer leaves of the cabbage that might overshadow the okra. Finally, we harvest the cabbage and leave the okra to grow to full size. This method saves space, and efficiently uses our time to help two crops with one weeding.

Okra plants can be huge by September!
Photo Pam Dawling

This post is part of what I have written about okra in my book Sustainable Market Farming. Buy the book to read the rest, including crop rotations, pests and diseases, harvesting and post-harvest care of okra.

Pickled okra, garlic scapes and beets.
Photo Bridget Aleshire

The Whole Okra

See my review of Chris Smith’s book The Whole Okra. Chris has grown 125 varieties of okra, and still counting, and cooked it in many different recipes. His book includes using the oil from the seeds, eating the leaves; making okra-stem drinking straws, okra seed tempeh, okra marshmallow delights; okra history and geography, medical and industrial uses and so much more. Here are instructions for freezing the sudden glut of okra that often arrives at some point in the summer, pickling (both by fermenting and with vinegar), drying (best when strung on dental floss). Best of all are the okra chips. Chris has a video of taste testing on YouTube, https://www.youtube.com/watch?v=sAy0pouxlME

Fruit for May

Flowers on a two-year-old strawberry plant.
Photo Kathryn Simmons

This is the first of my new monthly series, about small fruits that can be grown sustainably in a mid-Atlantic climate. I’ll talk about planting, pruning, harvesting and care of the plants, according to the season. I’ll give links to useful publications. I’ll have a focus fruit, and then more about others that need attention during the month. We do grow apples and pears, and some other tree fruit, but I’m not writing about those as I don’t have much recent experience.

Strawberries are the focus fruit for May

May is the month in our climate, to harvest and weed strawberries. Actually weeding strawberries in bare soil is a job that needs doing once a month from February to November here! We don’t have any strawberries in our gardens this year. Once upon a time, we grew matted rows, where you keep the same bed in production for multiple years, removing the oldest plants to make space for younger more vigorous plants. Weeds were our downfall. Once you let weeds seed in a strawberry bed, you have lost the battle. In our climate, we have cold-weather weeds and warm weather weeds. Semi-permanent strawberry beds get them all. I wouldn’t choose this method again.

See ATTRA Strawberries: Organic Production available free online, for a wealth of information. Updated April 2021.

Strawberries need a lot of weeding if grown on bare soil.
Photo Twin Oaks Community (Renee)

Harvesting strawberries

I recommend harvesting three days a week, in the mornings, once the dew has dried, to avoid spreading fungal diseases. Use shallow containers, although strawberries don’t crush as easily as raspberries. Turn each ripe-looking strawberry over to make sure it’s ripe underneath too. We will harvest with white tips, but not green. Commercial strawberries that will travel long distance are harvested ¼ green and arrive very red, but with not much flavor.

Nip through the stem of the fruit with your nails and set the fruit in the container. Also, now or preferably separately, collect up any moldy or bird-bitten fruits to compost. It’s better not to handle healthy plants after moldy fruit, but if you have dry weather and not many moldy ones, it’s very tempting to remove them as you go. When “Mouseberry”, our nickname for Botrytis grey mold, is only a minor problem, we just hurl each one as far from the strawberry bed as we can, rather than collect them up.

Unblemished strawberries can be stored for several days in the refrigerator. Do not wash before refrigerating, as this leads to rot. If you are planning to process lots of strawberries for drying, jam, juice or other value-added products, I recommend finding a simple little tool, a pair of round-ended tweezers about 2” (5 cm) long and ½” (1 cm) across. You can twist our the green tops quickly with minimal wastage.

A dormant bare root strawberry plant.
Photo Kathryn Simmons

When to plant strawberries

In case you don’t yet have strawberries, and now wish you did, here are some considerations about when to plant. Many gardening books are written in more northerly climates, where bare-root transplants are set out in early spring. But then it is necessary to pinch off the flowers the first year. And still weed once a month! We found it better here to plan for September planting of runners we had potted up in July, leaving them attached to their mother plants until time to make the new bed. They are less likely to die if still attached to the well-rooted mother plant. Fall-planted strawberries do not need to have the flowers removed in their first spring. It is not easy to find bare-root transplants to buy in the fall.

In Virginia, many commercial growers plant new strawberries on plastic mulch every year, buying in plugs. The costs are covered by the high price that strawberries bring in when sold. We were not selling, but feeding our intentional community. This means that produce that would get high prices doesn’t repay us for the time spent. We need nutrients for a well-balanced diet, not fancy stuff. This issue also came up for us when we grew ginger in our hoophouse. Tasty and enjoyable, but not lots of food for the space and time.

Newly prepared strawberry beds with landscape fabric.
Photo Wren Vile

As a balance, we settled on keeping two beds (one early variety, one late) for two years each, using landscape fabric with holes melted in it. Each year we would make 1 new patch, till in the older one after 2 harvests. Some years we bought plants, and we also figured out a good propagation method, which gave us plants when we needed them, without too much money or labor. We had backup plans in case we failed to propagate enough replacements.

In early June we’d prepare new beds if going for bare-root plants; after fruiting we’d dismantle the two-year-old bed, renovate the one-year-old bed, and in early July prepare the new bed if using plugs. We did the propagation of our own plugs during July, setting up a misting tent. We planted the new plugs in early August. I’ll go into detail about these tasks when we get to that time of year.

Patented varieties

Some varieties are patented and it is illegal to propagate your own without permission from the patent holder. It’s most illegal to sell plants you have propagated from a patented variety. Technically, it is also illegal to propagate for you own use, and even to let strawberry runners root themselves beside a mother plant. Not all varieties are patented. Cornell has a page Patent Status of Select Strawberry Varieties with info for varieties that do well in NY State. It includes when patents expire. StrawberryPlants.org has a lot of information, including an interactive variety list. Unfortunately, it doesn’t include info on which are patented.

We cover the new strawberry bed in newspapers and hay. Our method prior to using landscape fabric. Note the drip tape in position below the mulch.
Photo Luke Stovall

Climate change, challenges and options

Our climate is variable, and is changing to more of all extremes, so we need to change our systems to meet the challenges. It always helps to have a plan B.

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Fruit still available in May

If your rhubarb flowers, cut off the flower stems, preferably before the buds open, to keep the energy for the stalks.
Photo Pam Dawling

Rhubarb can be harvested until the stems get too thin. April is its main month here in central Virginia. Weed and water. Lop off any flower heads or buds, to concentrate energy into the stems.

Other fruit care in May

Install blueberry netting before the fruit sets, so the birds will have no reason to be interested. Weed, water, top up mulch, as needed. Check periodically to ensure the netting has no holes.

Grapes: Mow, weed, water in drought. Mow aisles as needed. New vines: remove side branches from trunks, and fruitlets. I like to walk through in May to record the condition of the grape vines.

A young grape vine in early May.
Photo Bridget Aleshire

Green Beans All Summer

A newly emerged bean bed with sunflower landmarks. When lilac is in full bloom, plant beans, squash, corn.
Photo Pam Dawling

Here I’m talking about snap beans, both bush beans and pole beans, often simply called green beans. By choosing appropriate varieties and giving thought to planting dates, you can get high yields all summer until frost.

Bean Varieties

We like Provider and Bush Blue Lake snap beans for productivity and flavor. We often sow Provider for the early and late crops, with Bush Blue Lake during the main season. Contender may have more flavor, but is less productive then Provider. Jade is a delicious, very tender bean, which grows well in hot weather, but will be a dismal failure if the soil is too cold. Our approach is to plant a succession of 6 sowings of bush beans, so we always have some at the peak of production.

Those who like flat beans often choose Romano II as a reliable producer of tasty beans whether it is hot or cool, wet or dry. Some people like yellow (wax) beans for visual diversity – the flavor is not much different from green beans. Purple-podded beans look attractive while raw, although the color fades on cooking.

Yellow wax beans.
Photo Small Farm Central

We have given up on pole beans as we don’t like putting up trellises. If the advantage of standing to harvest beats the disadvantage of putting up a trellis, you’ll prefer pole beans over bush varieties. Pole beans take a few days longer to mature but can then be picked for a longer period, if they don’t get damaged by the Mexican bean beetle. Half-runner beans can be grown with or without trellises, and are capable of high yields. We haven’t grown any we really liked.

Prepare for green beans

Beans tolerate a wide pH range, and like plenty of sun and well-drained soil. They definitely don’t thrive if flooded! An open site with good air drainage will help minimize mold problems and other leaf diseases. Bush beans take 50-62 days from sowing to first harvest, a bit less once the soil is really warm. A soil temperature of 77°F (25°C) is best for germination, although a temperature of 55-60°F (13-16°C) and rising is workable for dark-seeded varieties. Air temperatures of 65-85°F (18-29°C) are best for growth.

Like all legumes, beans produce nitrogen in their root nodules, although this doesn’t peak till after the beans are being harvested. In order to grow strong bean plants, you can fertilize before the beans at about 4 oz N/100 sq ft (13.4g/sq m), and use the bean-produced fertility for the following crop. If your soil is already very fertile, you could skip fertilizing before sowing the beans. Excess nitrogen will produce lots of leaves but delay flowering. 80-85% of the nitrogen produced ends up in the bean tops, so if possible turn them under before planting the next crop, rather then remove them to the compost pile.

Because they are not planted until spring is well underway, beds for beans can grow a good stand of winter cover crops ahead of the bean crop. Winter rye should be turned under three weeks ahead of sowing, to allow the rye to break down and for the allelopathic compounds to break down. We have found wheat to be easier to incorporate and to have less of an inhibiting effect on germination of the next crop. It is usual to avoid legume cover crops ahead of legume food crops, to reduce the likelihood of spreading pests or diseases. For the same reasons, it is better to grow beans where there have not been other legumes for 3 years. Sclerotinia white mold can be avoided by rotating with sweet corn or other grass crops, and avoiding nightshades, brassicas, lettuce, or other legumes. 

Newly emerged beans (in rather dry soil).
Photo Pam Dawling

Start beans as early as possible

We make our first sowing 10 days before the average last spring frost date, and cover the bed with rowcover. Dark-seeded varieties are more resistant to rot in cold soils, so use these at least for the first spring sowing. To speed germination, soak the seed overnight (up to 8 hours) in tepid water. If the sowing has to be postponed after the beans are soaked, rinse them twice a day and drain. Plant in 3 or 4 days. If you wait longer than that, the rootlets will be too long and fragile.

Sow your beans

If possible, ensure the soil has enough water before you sow, as watering after sowing can cause crusting and also chilling injury to the seed from the cold water. Avoid irrigation for two weeks after sowing to reduce the chance of the seed rotting. Sow 1” (2.5cm) deep, a little shallower in spring, a little deeper in hot weather. Place seeds 2-3” (5-7cm) apart. We use the wider spacing for new seed, and the closer planting for one-year-old seed. Two-year-old beans often have a germination rate of only 50%, and are not worthwhile. 

You can plant beans 2 rows to a bed, or on-the-flat in single rows with enough space to accommodate the pickers. The best spacing for optimum yield is 36 sq ins (232 sq cm) per plant. For example, 2” in-row x 18” between rows (5 x 46cm). Another advantage of close spacing is that the plants are more upright, with the beans higher in the leaves. This is less space than recommended for areas prone to fungal diseases.

Planting soaked inoculated beans through holes in plastic.
Photo Brittany Lewis

Beans host nitrogen-fixing bacteria in nodules on the roots, and if you are growing beans on land that has not grown legumes before, or it’s spring and you don’t want to rely on the existing bacteria waking up, add some powdered inoculant. You could add this at each sowing, as it is cheap and easy, especially if the beans have been soaked. Simply scatter some of the black powder on the beans as if you were adding pepper to your dinner, then stir the seed gently. Each bean needs only a few specks of the inoculant to get started. Contrary to any rural myths, the inoculant does not speed germination.

Care for your beans

Don’t cultivate or harvest while the leaves are wet, since anthracnose, bacterial blight and rust disease are more likely to spread under these conditions. Hoe or machine cultivate while the bean plants are still small, and once they grow taller and bush out, few weeds will cause trouble. We have tried sowing beans through biodegradable plastic mulch, poking holes with rods and popping the seeds in. This crop stayed very clean, and withstood a drought caused by a crew member mistakenly pulling the drip tape out too soon. Sowing took a long time, and anyone tempted to try this would be advised to make a jig that punches multiple holes at once. In that way, the saved cultivation time, lack of diseases, and extended life of the plants might balance out the extra sowing time.

Using the bean dibble to punch holes through the plastic mulch (the soil is holding down the edges of the mulch).
Photo Brittany Lewis
Beans growing on biodegradable plastic mulch.
Photo Nina Gentle

Irrigation is most needed during bloom, pod set and pod enlargement. Time the watering so that the leaves dry before nightfall. Beans need around 1” (2.5cm) of water until the end of May, then up to double that in summer.

Carry on sowing beans as late as sensible

To calculate your last worthwhile sowing date, subtract the number of days from sowing to harvest from your first frost date. Then count back a further two or three weeks, whatever would be a worthwhile length of harvest period for you. If you don’t have rowcover for when it turns chilly, count back another week or two in case frost is extra-early. Our first frost could be October 14, and counting back 60 days gets us to mid-August. We go with a last sowing in early August. We pay attention to weather forecasts, and when frost threatens, we cover with rowcover on the cold nights. Usually this lets us get several more pickings before any serious cold weather arrives. During the day, rowcover would stop pollination, but it does not stop beans that have already set from growing to full size.

Bad damage from Mexican bean beetles on these bean leaves. Beetles will also attack the pods after a while, making them inedible.
Photo Wren Vile

Plant beans often for continuous harvest

Before we discovered the Pedio wasps to kill the Mexican Bean Beetles, we needed a new patch of beans coming into production every 2 weeks. We made 7 plantings at 15 day intervals. We now plan for a new patch to harvest every 20 days, sowing 6 times rather than 7. As well as saving space and sowing time, we get more beans than previously. Some of the time we pick from two overlapping patches.

To calculate the best planting dates for your farm, you’ll need four pieces of information: first possible planting date in spring, last planting date that will provide a crop in time before fall frost, first harvest date from each sowing you’ve done, and the number days you want to be picking from the same plants. For us, space is tight, and we want to pick from the same plants for 3 weeks, after which the yield goes down, and it takes too long to “search” for the ripe beans.

We determined our earliest possible and latest worthwhile harvest start dates, and then divided the period in between into a whole number of intervals. In our case we went for 20 days. If we expect the first beans to start coming in on 6/16 and the last ones on 9/24, then the period in between is 100 days long. If we want fresh beans every 20 days, we’ll need a total of 5 intervals between plantings, which is 6 sowings.

A May sowing of Provider beans in late June.
Photo Pam Dawling

Our records tell us that for harvest dates of 6/16, 7/6, 7/26, 8/15, 9/4 and 9/24, we need to sow 4/20, 5/14, 6/4, 6/26, 7/19 and 8/7. In practice we use sowing dates of 4/16, 5/14, 6/7, 6/29, 7/19 and 8/3. Notice that beans mature faster in warmer weather, and to keep up with them, we need shorter planting intervals later in the summer. Our sowing intervals are 28, 24, 22, 20 and 15 days.

Harvest your beans

We pick beans three times a week, going for pencil-sized pods with pliable tips. In our climate, beans can size up in two days. It’s important to nip through the stem of the pod, and not leave the cap part on the plant, as this is the part which signals to the plant whether to continue cranking out beans or stop and focus on ripening seed. For the same reason, it is important to pick and discard any oversize pods.

Like many warm weather crops, beans are liable to chilling injury if over-refrigerated. If possible keep the temperature above 40°F (4.5°C), or you risk having the beans become slimy and pitted. At 40-45°F (4.5-7°C) and 95% humidity, beans can be stored for 7-10 days. Temperatures above 45°F (7°C) are likely to lead to yellowing and development of fiber.

A plentiful supply of beans!
Photo Kathryn Simmons

Watch out for trouble

Scout the fields once a week, and keep a weather-eye open while harvesting or cultivating, to spot small problems before they become large ones. See the Cornell University 2016 Organic Production and IPM Guide for Snap Beans for detailed organic disease and pest control information.

Lifecycle of the Mexican bean beetle.
Photo Purdue University

By far the worst pest of beans we ever deal with is the Mexican Bean Beetle, a yellow-bronze beetle with eight black spots. Adults overwinter in plant debris, so clean up well in the fall, and try not to have your first bean planting be near the site of your last one the previous year. Here, the MBB emerge on the first cloudy day in early June. We used to flame each bean planting when numbers and damage became intolerable, and move on to the next planting. A smarter move would have been to plant a small early trap crop of beans deliberately at or near the site of the late beans the previous year, and then flame the trap crop when there are larvae, but not yet any pupae.

Nowadays we buy the parasitic wasps Pediobius foveolatus, ordering them as soon as we see the fuzzy yellow MBB larvae, which is the stage the wasps attack. The package contains mummified MBB larvae, with the wasps on the point of hatching. Set the open container under the bean plants close to some MBB eggs and larvae. Sometimes I shake out a few mummies here and there along the row. Once hatched, the wasps are very mobile, and will likely take care of your neighbors’ MBB as well. The Pediobius do not overwinter in our climate, but we have found that good control for a few years reduces numbers so that we can sometimes take a year off from buying the parasites.

See Using Pediobius Foveolatus as a Biological Control for Mexican Bean Beetles on Organic Vegetable Farms by Kim Stoner. Suppliers come and go, apart from the Phillip Alampi Beneficial Insect Rearing Laboratory, who we have been buying from for many years. Two other suppliers are Bugsforgrowers.com and Arbico, Read the instructions here.

Other insects that can damage bean crops include bean leaf beetle, potato leafhopper, seedcorn maggot, European corn borer and tarnished plant bug. Mites and slugs can also cause trouble.

The main defenses against disease are to keep the leaves as dry as possible. Consider orienting the rows to take advantage of the prevailing winds, planting on raised beds, using wide row spacing or in-row plant spacing.

Fungal diseases tend to be furry. Botrytis Grey Mold and Sclerotinia white mold are the most common.

Bacterial diseases of beans cause sunken or water-soaked brown spots perhaps with paler margins, on leaves and pods. Virus diseases cause leaves that are typically mottled, blistered or curled.

Most likely, it will be you enjoying your beans and not pests and diseases!