A few weeks ago I wrote about clearing tomato plants, and mentioned our hoophouse troubles with nematodes. Nematodes are tiny soil-dwelling worms that have a wide host range and are hard to control. They move only 3’–4′ (1–1.2 m) per year on their own, but people move them on shoes, tools, etc. We have had peanut root-knot nematodes (Meloidogyne arenaria) since 2011 when we found them in spinach transplants we were growing for outdoors in early spring.
In my August 2014 post Good news – great hoeing weather! Bad news – more nematodes in the hoophouse I wrote about solarization to fight nematodes in our hoophouse (scroll down to the end of the post). The post includes a photo of our first attempt at solarizing – a bit of a How Not To! Be sure to use UV-inhibited polyethylene. This year we somehow got some construction plastic mixed in. It doesn’t work! It goes cloudy (thus not heating up the soil) and it shatters into little pieces.
My most thorough blogpost about nematodes was in 2018 for Mother Earth News: Managing Nematodes in the Hoophouse.
My postSolarization and crop choices to fight nematodes in August 2019 includes a photo of a much better way to solarize an individual bed. In that post I gave a list of nematode-resistant food crops, and also talked about cover crops. There is a photo of nematodes on cucumber roots there too).
Food crop choices to fight nematodes
Most resistant and most helpful are the Juncea group of mustards. I did some research into more Juncea options in Solarization and crop choices to fight nematodes. We don’t like very pungent greens, so we have not yet taken the route of planting a whole bed of Juncea types. Instead we have mapped and flagged the nematode-infested areas of our beds, and try to be mindful of what we plant in those spots. Three of our seven beds have no nematodes so far.
This year we looked at the nematode map we had made and decided to focus our attention on the bed with the highest number of nematode patches, and grow the most resistant winter crops (of the ones we like to grow) there. That’s the frilly mustards (Ruby Streaks, Scarlet Frills, Golden Frills, all Juncea mustards, and Mizuna, a Japonica mustard), Yukina Savoy (variously reported to be Brassica juncea, Brassica rapa pekinensis, and Brassica rapa), and Russian kales (Brassica rapa).
Mapping nematode areas
See the post with info from Gerry Ross I mentioned above. We have previously tried for a “Two years good, One year bad” strategy. This was to grow nematode-resistant crops in the infected areas for two years, then try risking one year of susceptible crops. That was a bit demanding on careful management, and we haven’t kept that up.
A reader asked about cover crop choices to fight nematodes. In June 2019 I wrote about using marigolds, sesame, Iron and Clay cowpeas as warm-weather nematode resistant cover crops. We’ve also used winter wheat (in winter!), and white lupins (not worthwhile, in my experience). See that post for a few other ideas on nematode-fighting cover crops, and why we decided against some options. At that time, we decided not to grow sunnhemp (Crotolaria) because it is poisonous, although newer varieties of Crotolaria have lower toxin levels. More recently we have been growing sunnhemp, after I saw it growing so well in North Carolina. It is a warm-weather legume, so it is feeding the soil while tackling the nematodes. It does grow tall in the hoophouse, and we have taken to chopping it down with hedge shears to an ergonomic elbow-height every few weeks whenever it gets too tall. The cut tops create a nice “forest-floor” mulch effect. You can almost feel the extra organic matter nurturing the soil! (High OM levels deter nematodes.) 60-90 days to maturity.
We previously used soybeans as a short-term leguminous summer cover crop, but they do not offer the nematode resistance. Iron and Clay, Mississippi Silver and Carolina Crowder cowpeas are all nematode-resistant and can be grown in summer instead of soybeans. Sesame is a legume that is particularly good against peanut root-knot nematodes.
A Florida reader gave me information about partridge peas, which I have not yet tried: After terminating cool-season brassicas and celery between April and June, their late spring sowing of partridge peas were too late this year to be productive, because the hard seed was very slow to germinate. Partridge pea could be a good cover crop for mid- to late-summer, if you scarify those hard seeds to speed germination.
Some cover crops can be alternate hosts for pathogens like cercospora, rust, or bacterial leaf spot, so be on the lookout for new problems while solving old problems. In the deep south, beans, yard-long (asparagus) beans, and cowpeas can succumb to heat, nematodes, rust, bacterial spots, and other pathogens and pests. Senna (tall) and Partridge pea can provide “chop-and-drop” organic matter as sunnhemp does. Sunn Hemp can host foliar pathogens (some possibly seed-borne), in Florida, and does not reliably form nitrogen-fixing nodules on the roots, even when inoculated. Even so, it is useful as a fast warm season green manure cover.
The flower Gaillardia (blanket flower) is a quick-to-compost, chop and drop option for late winter to late spring, It decomposes quickly, and can provide a quick green manure. Gaillardia is nematode-resistant, great for beneficials and pollinators, but is susceptible to some foliar pathogens later in the season. You can sow Gaillardia in August, or even later in fall for early spring flowering.
Due to climate change, and the more year-round activity of nematodes, pathogens, and pests in Florida, they’ve been including more nematode-resistant grasses into their rotations. We all need to be thinking more about warmer-climate options, as climate change continues to push pathogens and pests farther north, earlier each year.
If you don’t already have a crop rotation plan, this is the time to put one into place, especially if a lot of your ground is taken up with sweet corn every year! Our sweet corn occupies a lot of our space, so we pay attention to crop rotation. Corn is the only crop in the grass family that we grow, so this is not hard. We keep two or three years without corn between the corn years. Here’s the crop and cover crop sequence for each of our six sowings:
Sowings 1 & 2: The winter before the corn, we have a winter-killed cover crop of oats, (or sometimes a clover patch which has been growing all the previous year). Half the patch of this early corn is followed by oats in August and then garlic in early November. The other half gets oats and soy in August, to be winter-killed. This area will be easy to work up in early spring for our broccoli and cabbage.
Sowings 3, 4, & 5: The previous winter cover crop is winter rye or wheat with crimson clover (if we sow before 10/14) or winter rye or wheat with Austrian winter peas if after 10/15. The corn is followed by more rye or wheat and crimson clover in October. The following year we will plant potatoes here in June. The clover will have plenty of time to reaching flowering and therefore have plenty of nitrogen nodules on the roots.
Sowing 6: The previous winter cover crop is winter rye and Austrian winter peas. We undersow this corn with oats and soy. We mow high after harvest, and leave the oats and soy to grow until winter-killed. This patch is easy to prepare for our potatoes in March.
For the later sowings of sweet corn, a good stand of a preceding winter cover crop mix including legumes can provide all the nitrogen the corn needs (100-125 lbs/acre; 112-142 kg/ha). The nitrogen nodules on the roots contain the maximum nitrogen when the legume reaches its flowering point, so this method doesn’t work for early sowings.
No-till planting into strips tilled in a white clover living mulch sounds good but has been found tricky. Jeanine Davis addresses this in NCSU’s Organic Sweet Corn Production. The clover can out-compete the corn, become invasive and hard to get rid of. Soil temperatures will be lower (a disadvantage in spring) and slugs and rodents may increase. Trials of sowing corn into rolled and crimped hairy vetch are underway.
Undersowing (interseeding) cover crops such as white or crimson clover into the corn at the V5 or V6 stage is more successful. Ensure good seed-to-soil contact. The clover grows after the corn dies.
Some growers undersow with forage brassicas at last cultivation. Research shows this does not reduce corn yields. The forage can be harvested after the sweet corn harvest finishes.
Caring for Sweet Corn
Never allow soil in corn plantings to dry out, especially with close planting. You might need more than 1” (2.5cm) per week for maximum productivity, although corn is more drought-tolerant than some crops. The most important times for watering are silking (when the silks first become visible) and while the ears are filling out. We use overhead irrigation for corn, which works well to also water undersown cover crops.
Corn plants closer than 8” will compete with each other, so be sure to thin. People used to recommend removing the suckers that came from the base of the plant, thinking it led to higher yields. This has been tested, and in fact it can damage plants and possibly even reduce yields. (Reports from Clemson and Colorado State).
Sweet corn needs cultivating at least twice, at two weeks and four weeks after sowing. Even better are four rounds: at 7, 14, 21 days and finally one around 35 days when plants are 18-20” (45-50cm) high. Corn is shallow rooted so avoid deep cultivation. We use a walk-behind BCS tiller, followed by hoeing (and thinning at the first cultivation).
Each time we sow sweet corn, we wheel hoe or till between the rows of the previous planting, hoe and thin the plants to 8-12” (20-30 cm). We also till between the rows of the corn planting before that, hoe, and sow soybeans. Although they don’t supply the highest amount of nitrogen compared to other legumes, they are cheap, quick, somewhat shade tolerant, hinder weeds, and withstand foot traffic during harvesting.
While harvesting the corn we pull out any pigweed that has somehow survived our earlier efforts. Pigweed puts out its seeds in one big burst, so pulling up enormous pigweed is worthwhile, if it hasn’t yet seeded. Our soil has improved over the years, so it is now possible to uproot the 5ft (1.5 m) pigweeds. Sometimes we have to hold the corn plant down with our feet, but we do almost always succeed in getting the weeds out.
It is helpful to understand corn growth stages so that you know when the plant is most susceptible to damage, and when to take action. Corn growth stages are divided into vegetative (V) and reproductive (R). Stages are determined when at least 50% of the plants have reached or are beyond a particular stage.
Vegetative stages begin at emergence (VE), and each leaf with a fully developed collar is a new stage. Leaves within the whorl, not fully expanded and with no visible leaf collar, are not counted. Most sweet corn hybrids produce 18-21 leaves. Vegetative growth takes about 55-60 days after emergence. V3 (three leaf collars) begins 2-4 weeks after VE, and plants switch from using kernel reserves to photosynthesis and roots for nutrients.
Around V4, broadleaf weeds will stunt yields and should be removed. By V5, the numbers of potential leaves and ears are determined. Plants are 8-12” (20-30 cm) tall and the growing point may still be underground. Tillers (suckers, branches that grow from the lower five to seven nodes) appear.
V6-V8 –Beginning 4 to 6 weeks after VE, the growing point emerges above the surface, making the crop susceptible to frost, hail and winds. Beginning at about V6, the lower leaves may fall off naturally. At V7, rapid growth begins, and the number of kernel rows is determined. The number of potential kernels per row begins is set between V7-V16. By V8, the plant reaches 24” (60 cm) tall.
V9-V11 – At V9, tassels (not yet visible) and ear shoots are developing. New leaves appear every 2-3 days
V12 – The plant is 4ft (1.2 m) tall or more. Nutrients and water are important from this stage until the start of the R stages. The leaves are full-sized and about half are exposed to sunlight. “Brace roots” develop and the number of kernels per ear and size of the ear are set. Kernels can be damaged by insects and hail.
V15 – The plant is two weeks away from silking. Tassels are almost full-sized, but still hidden. Moisture and nutrient shortages now result in shorter ears and lower yields.
VT –Beginning 9-10 weeks after emergence, good pollination is essential to develop the kernels. Tassels are fully visible and silks emerge in 2-3 more days. Pollen shed begins, continuing for 1-2 weeks. Hail can be very damaging at this stage. Vegetative stages end when the corn develops a tassel (male flower). It takes about 20 days from tasseling to ripe.
R1 – The plant has silks outside of the husks and is at its most vulnerable. Environmental conditions can greatly affect pollination. The worst is drought, which dries the silk out, reducing its ability to collect pollen falling from the tassels.
R2 (“Blister”) stage – The kernels are filled with clear liquid. About 12 days after silking, the silks darken and dry out. Stress (especially drought) can cause kernels to abort.
R3 – Milk stage – About 20 days after silking, kernel fluid turns milky, as starch accumulates. The effects of stress are not as severe after this stage, but can still lead to shallow kernels.
R4 – Dough stage – About 26 days after silking, the kernels have a dough-like consistency. Stress can produce scrawny kernels.
The dent stage (R5) and full maturity (R6) will only happen if you leave the plant to produce seed.
Corn growth stages can be estimated using corn growing degree days (GDD), accumulated daily from the date of planting. GDD are calculated by averaging the max and min temperatures in a 24-hour period. 50°F (10°C) is subtracted from that average temperature to give the GDD for the day. A Corn GDD Tool is available at the High Plains Research Climate Center. Stress, especially drought, can affect growth and GDD alone may not provide an accurate estimate of growth stage.
I enjoyed attending the in-person conference of Pasa Sustainable Agriculture. This is the first conference I’ve been to in person in two whole years. PASA did a lot to ensure the conference was as Covid-safe as possible. They limited the number of attendees (there were still plenty to ensure lots of chances to exchange information). Everyone had to test on their day of travel to the conference, and speakers had to test every day of speaking. For me that was all three days. Everyone was masked, nearly all with KN95 “real” masks. The hotel housekeeping staff only came in after we left. (We could have requested the service, but, heck, I can make my own bed!) In the workshop rooms, the chairs were spaced 6 ft apart. The trade show had wide aisles, and meals could be taken out of the dining room to a quiet spot. Just getting to be there was a big highlight for me! I left feeling energized and enthused, and very grateful to the PASA team for preparing such a successful event.
There were four sessions of workshops each day, with one-hour breaks between, allowing time to visit uncrowded trade booths, catch up with old friends, and make new ones. We were well-supplied with snacks and beverages during the breaks. There were socials with more snacks at the end of the day.
I did have trouble with the conference app, but then, my phone is limited in what it can do. Likewise I failed to upload my slideshows to the platform, so I ran them off my flashdrive. My pdf handouts did make it onto the app, so if you wanted one of my handouts, you can find it there and here:
Each of the ten workshop sessions had a choice of eight or nine workshops. I had thought I might hunker down in my hotel room when I wasn’t speaking, to minimize my chance of catching Covid, but as permaculture author Darrell Frey said “This feels safer than going to the grocery store!”
I enjoyed several workshops presented by others, including:
On-Farm Experience with Organic No-Till
Sam Malriat from Rodale
No-Till sequesters carbon in the soil, but simply never tilling does not improve the soil. Chemical no-till uses lots of herbicide. Don’t be obsessive about no-till. Shallow tillage can be a responsible choice, as incorporation of organic matter is valuable. Adding cover crops, compost or manure, grazing, and a good crop rotation, can increase the OM, and thus increase the soil water capacity enormously.
To overcome the challenges of no-till, you need a very good cover crop stand that will provide a thick mulch when terminated; a competitive cash crop; a way to plant into the residue, and a back-up plan in case one of the requirements doesn’t pan out.
Sowing corn into rolled and crimped hairy vetch does not work well, because corn is a heavy feeder and not very competitive. Better is to undersow the corn at V5 or V6 (stages of vegetative growth) with white clover or crimson clover in September. It’s important to get good seed to soil contact. The clover grows when the corn dies. This is in Rodale Country in PA. If the clover can be left growing until the second year, cabbage can be transplanted into it. His slides showed the success of this system after an unpromising start.
Pumpkins can be direct seeded in crimped and rolled (or mowed) winter rye. There is a lot of difference in thickness of the mulch between rye sown in August and October.
Organic Solutions: Pest Management
Drew Smith and Emily Gantz from Rodale
There was a big drop in pesticide use in the mid 1990’s as GMO crops came in. But then a big uptick as resistance to the GMO crops developed. Currently, almost all non-Organic seeds contain neo-nicotinoids, even though they provide no economic benefits.
Crop rotation is the single most important thing you can do to manage pests. Drew showed us the IPM triangle, and we worked our way up. To succeed in preventing pest infestations, planning of all aspects of growing the crop is vital. As is regular scouting of each crop. Cultural controls include the physical aspects of the planting. Other physical controls include mechanical aspects of growing the crop. Biological controls include encourage beneficials, releasing biological agents. Greater biodiversity provides greater stability. See Cornell Entomology https://biocontrol.entomolgy.cornell.edu/index.php
Native Pollinators: Identification, Habitat Needs and Resources
Sarah Koenig and Ryan Stauffer from the Audubon Society
There are 4000 species of bees in the US (20,000 globally). 70% of food crop species rely on honeybee pollination to some extent. Native bees mostly nest in the ground. Don’t kill them by compaction (or weedkillers!). Use native flowers to attract native pollinators.
Using Tarps to Reduce Tillage on Small Vegetable Farms
Ryan Maher, Cornell Small Farms & Bob Tuori, Nook and Cranny Farm
More growers are trying tarping for weed control, killing cover crops, maintaining a good soil temperature, avoiding crusting and compaction, keeping beds dry enough for planting and reducing dependence on single-use plastics. Challenges include the heavy weight, the aggravation of using sand bags, especially in windy places, ponding of rainwater runoff, and the frustration of providing perfect vole habitat.
After 28 days in summer, you gain 200 GDDs. Plant-available soil N increases by 2 or 3 times from the plant residues. How soon does it dissipate after removing the tarp? Tarping for 3 weeks after shallow tilling kills the living weeds, improves crop establishment and reduces weed emergence by up to 83%. Think of tarps as a tillage tool! Do plan for weed management after removing the tarp. Pigweed and amaranth can become worse!
Bob Tuori spoke about a SAREtrial of tarping in the Northeast. He compared potatoes grown with and without prior tarping, both patches with and without hay mulch after planting. The tarped area needed sandbags every 10-15 ft. The tarp was removed June 4, weeds were counted June 24, then the patches were mulched. (I hope I got that right). I did not write down all the results, but the only-mulch area grew 17.4 lbs per hour of work, and the tarp-only area grew 13 lbs per hour of work. See the SARE report for the details.
Harvesting Techniques for Small- to Mid-Scale Vegetable Farms
Julie Henninger of Good Keeper Farm and Matthew Lowe
We saw good tool and equipment storage, and learned the benefits of growing head lettuce on landscape fabric (no rotten bottom leaves, no weeds). Muir is their favorite lettuce for spring, summer and fall. At $3/head, a 95ft row planted at 9” spacing earns them $1300, if they have a 15% loss.
We learned the importance of sharp knives or scissors for cutting baby greens with minimal cell damage and browning. Theirs sells at $12/pound. They grow Salanova, which brings in $1140/bed at each cutting. If they cut whole heads, these bring in $1476 per bed.
For loose carrots, they sow rows in pairs 2” apart, with 6 rows on a 30” bed, using a stale seed bed and flaming. They sell 1000 lbs per week. Julie Henninger emphasized not wasting time by setting the carrots down in piles. Minimize the number of times each crop is touched. They have modified a cement mixer to wash 25-45 lbs at a time.
Training and communication are also very important. New workers must master the task first, before chatting. Minimize distractions. Send crews out with a strong role model each, to keep the crew working at a sustainable pace. If working with a crew with diverse abilities (eg children), provide a clear short task with a beginning and an end, to give a good sense of achievement.
I participated in the book swap, setting out some spare handouts I had in exchange for a couple of magazines. I enjoyed the Farm Innovations poster display of tools and techniques to improve production or save resources (or both). I liked that previous years’ posters were available as pages in several ring binders.
In the Trade Show there were 60-odd vendors. I checked in with Nifty Hoops, a company who will deliver a hoophouse and put it up for you in one day, or help you put it up, teaching as you build. We put ours up ourselves, in 2003, and we were inexperienced and slow, and had to work on it in the (hot) afternoons, after spending the mornings farming. At events when I talk about hoophouse growing, I’ve sometimes been asked if there are companies who will erect hoophouses (high tunnels), so it’s good to be able to pass on this contact. Nifty Hoops also sell interesting components such as DC-powered inflation blowers. (734) 845-0079. They have videos on their Facebook page
I picked up some publications from ATTRA, who have supplied me with great vegetable growing info since before the internet. (We used to call them up and ask for publications to be sent in the mail).
I also was fascinated by the Mini-Treffler, from OrganicMachinery.net, a manual rolling tine harrow for crops in beds.
The TINY Treffler is a hand drawn harrow with the working width of 80cm (2 ft 7 in), 100 (3 ft 4 in) and 130cm (4 ft 3 in)
Shares the same principle with the big Treffler harrows: in the row harrowing, adjustable tension and the patented tine suspension
Each tine follows the contour of the field and the downward pressure remains constant
The TINY is effective throughout the growing season in greenhouses or for small enterprises in vegetable production or seed propagation
Wheels extendable from one or both sides to straddle a bed
I gathered literature for our garden crew as well as our dairy, orchard and poultry people, and an assortment of free pens, notebooks, stickers.
PASA also had a virtual conference, spread out over a couple of weeks in January. I’m sure there was great information there too, but our rural internet is not up to the task of virtual conferencing, so I’m in the dark. Pasa intends to keep a virtual conference next year as part of the mix – it works better for farmers who cannot easily leave the farm, it reduces the carbon footprint of travel, and saves on travel and hotel or BnB costs. Maybe next year I’ll have better internet. Maybe Covid will have receded. This year’s conference was great! I look forward to next year’s!
Organic Growers School, based in Asheville, North Carolina, is also open for applicants for their Journeyperson program and their year-long Farm Beginnings program
Journeyperson Programis for those who have been farming for 3 years and are looking to grow a farm business. Join Nicole DelCogliano, August 26th, at 7 pm for a Journeyperson Info Session. via Instagram Live! Nicole will answer your questions about our Year-Long Journeyperson program, (which starts in November 2021 and ends in October 2022), and discuss options to meet your farming needs.
Organic Growers School Farm Beginnings Program
Farm Beginningsis a year-long training program, including Whole Farm & enterprise planning,Connection to a farmer network, Growing season learning plan, On-Farm Field days & workshops. This is for those who have already considered making a career of farming, and have taken some steps in that direction. Deadline for this year is September 18. Click the title link and watch the video.
Following on from my recent post about planning winter cover crops, here’s something else useful: SARE has a new video “Cover Crops and Soil Health” which illustrates how producers can use cover crops to improve productivity and sustainability.In just a few short minutes, “Cover Crops and Soil Health” outlines how cover crops can build soil structure, protect water quality, suppress pests and improve a farm’s bottom line.
Combining cover crops and reduced tillage can also help farmers:
Manage soil nutrients
Reduce erosion and compaction
Improve water holding capacity and infiltration
Reduce input costs
“Cover Crops and Soil Health” is now available for viewing and sharing at www.sare.org and on YouTube. Farmers, ranchers, educators and other agricultural professionals may download or embed the video without modification into websites or other noncommercial educational presentations. The entire “What is Sustainable Agriculture” series is also available on YouTube. This video series was produced through a collaboration of the Sustainable Agriculture Research and Education (SARE) program and Pixeldust Studios.
If you haven’t already made a plan for winter cover crops, this is a good time to do it. Having plants growing through the winter, or at least into the winter until they get killed by cold temperatures, will improve your soil both physically (the roots hold the soil in place, preventing erosion, and they open up channels that improve the drainage) and biologically (the soil microorganisms thrive when they have active plants to cooperate with, exchanging nutrients). Cover crops will also reduce the number of weeds you have next year, because they crowd out weed seedlings. In some cases they even inhibit weed seeds from germinating.
I have some slideshows about cover crops, and am including one at the end of this post.
Choosing the “perfect” cover crops can be confusing, but any is better than none, so I encourage you to experiment and keep records, so you can improve your choices each year. It helps to know your first frost date, and your winter-hardiness zone (the lowest temperature your garden is likely to encounter). A two-week delay in sowing can seriously reduce the effectiveness of the cover crop, so follow these guidelines if you can.
Short Simple Guide to Winter Cover Crops
If the area has been fully harvested of food crops by 60-80 days before frost, sow a frost-killed cover crop or even a fast-growing food crop. Buckwheat, soy, cowpeas, spring peas, sunnhemp, Japanese millet, sorghum-sudangrass will frost-kill. Forage radish lab-lab bean or bell beans will die back and leave almost bare soil. Don’t sow a winter cover crop yet. If sown too early, oats head up in the fall and even drop seed.
If the area is clear of vegetable crops by 40-60 days before frost, sow oats to winter-kill. If possible add a legume (soy and spring peas are easy, and will be killed by the frost, so they won’t complicate food crops next year). For us with a first frost date of October 14, the cut-off date for oats is September 7. This would be after growing early sweet corn, spring broccoli, cabbage, spring-planted potatoes or early season spinach, lettuce, beets, carrots. Oats will winterkill completely at 6°F (-17°C) or even milder than that, leaving the plot quick to prepare for early crops next year. So plan to put your early crops where you had oats in the winter. See the slideshow for more about oats.
If the area is ready for cover crops 20-40 days before frost, sow winter wheat. Add a legume such as crimson clover, if you won’t need to prepare the area before it flowers (in central Virginia 4/16-5/2, most usually around 4/20). You get the most nitrogen from the legumes if they reach the flowering stage before you kill them off in spring. If you have a legume that doesn’t reach flowering, it’s not the end of the world, you just get less nitrogen for your money. It is too late to usefully sow cover crops that are not frost-hardy, or even oats, which won’t make enough growth before getting killed.
If the area is ready for cover crops up to 10 days past the frost date, sow winter wheat or winter rye and hairy vetch or Austrian winter peas. Winter rye is hardier than any other cover crop and can take later planting dates. But it is a bit harder than wheat to incorporate in the spring. Austrian winter peas can be sown later than other legumes.
If you are up to3-4 weeks past your average frost date, (we choose November 7 here, where our average first frost is October 14), sow winter rye alone. It’s too late for any legumes.
If you are later than 3-4 weeks past your average first frost date, leave the weeds or crop remains growing. It’s too late to sow a cover crop, and you’ll do more harm than good tilling up the soil. You can mow the weeds anytime you see lots of flowers and seed heads. The weed roots will hold the soil together and help feed the soil microorganisms until early spring. Be prepared to act soon in spring, so you don’t get weed seeds.
More Options for Each of These Time-frames
60-80 days before frost: You could follow a frost-tender cover crop with an over-wintering cover crop, for best effect. If you leave the dead tender cover crops in place, in early spring the winter weeds will start growing in the open space, so be ready for fast action. For the very earliest spring crops, forage radish lab-lab bean or bell beans will die back and leave almost bare soil. While still growing, they suppress weeds. BUT fast-maturing spring vegetables will not do well with no-till cover crops unless you add N fertilizer, as they need nitrogen more quickly than can be got from no-till.
40-60 days before frost: Austrian winter peas, crimson clover, or red clover are other options for legumes, but they won’t die when the oats do. They are relatively easy to incorporate in spring. Frost-killed cover crops can also be combined with oats. Or for a cover crop to survive the winter, sow winter barley or winter wheat with Austrian winter peas, crimson clover, hairy vetch, red clover, fava beans. Hairy vetch takes a few weeks longer than crimson clover to reach flowering. Which you choose will depend what you want to grow there next spring and when you need to plant it. After oats or other winter-killed cover crop, we like to plant our early spring food crops, peas, cabbage, broccoli, carrots, March-planted potatoes, spinach and the first sweet corn.
20-40 days before frost: Winter rye, or winter barley are also options for the cereal grain part of the mix, if you have those seeds on hand. In central Virginia, it’s a mistake to sow rye as early as August, as it can set seed. Austrian winter peas, or red clover are other legume options if that’s what you have. Sometimes it pays to use what you already have, as it may not give good germination if saved over to next fall. Winter rye needs 3-4 weeks after tilling in, in spring, to break down and to disarm the allelopathic compounds that stop small seeds germinating. Plan for the next food crops to be ones planted after late April, such as late corn plantings, winter squash, transplanted watermelon, tomatoes, peppers, sweet potatoes, June-planted potatoes, fall brassicas, and second plantings of summer squash, cucumbers, beans.
Up to 10 days past the frost date: it’s too late for clovers. Austrian winter peas winter-kill in zone 6, but are hardy in zone 7. Hardy to 0°F (-18°C). AWP bloom in late April at Twin Oaks, before hairy vetch. Suitable crops in the year before using Austrian winter peas are the late-finishing winter squash, melons, sweet potatoes, tomatoes, peppers, middle sweet corn, June-planted potatoes. The same group of crops are suitable for following AWP, as they are planted after May 1. You can sow AWP several weeks later than clovers, but at least 35 days before first hard freeze (25°F/-4°C) – in zone 7, 8/10–10/24 (11/8 is sometimes OK)
Up to3-4 weeks past your average frost date: no really, it’s too late for any other cover crop. If you don’t have winter rye, don’t till! Leave the weeds, see below.
Later than 3-4 weeks past your average first frost date: no, really, do not till! You could mow and tarp, to kill the weeds before spring. I’m not sure what the soil life thinks about that, though! You could mow again in early spring, or till and sow oats, if you won’t be planting a food crop in the following 8 weeks, giving the oats time to make respectable growth before turning them under.
Create a crop rotation for vegetables that includes good cover crops
If you include winter cover crops when planning a crop rotation for your vegetables, you can tweak your plan to maximize your cover crop opportunities. Here’s the steps:
Figure out how much area is needed for each major crop (the ones needing the largest amount of space).
Measure and map the space available
Divide into equal plots big enough for your major crops
Group compatible crops together to fill out each plot
Set a good sequence, maximizing cover crop opportunities
Include best possible cover crops at every opportunity
Try it for one year, then make improvements
For more details, see my slideshow Crop Rotations for Vegetables and Cover Crops on SlideShare.net
Advanced Options for Winter Cover Crops
Sometimes you can undersow the cover crop between the rows of a growing food crop, to take over after the food crop dies of frost or mowing. We do this with our last planting of sweet corn, and with fall broccoli and cabbage.
Timing is critical: Sow the cover crop late enough to minimize competition with the food crop, but early enough so it gets enough light to grow enough to endure foot traffic when the food crop is harvested. The leaf canopy of the food crop should not yet be closed. Often the best time is at the last cultivation, often about a month after planting the food crop. With vining food crops, it’s important to sow the cover crop before the vines run.
Choose vigorous food crops, but cover crops that are only moderately vigorous. Ensure the seedbed is clean and the soil crumbs small enough. Use a high seeding rate, whether broadcasting or drilling, and irrigate sufficiently.
No-till Winter Cover Crops
In the spring, kill the cover crop without tilling it in, and plant food crops into the dying residue. There are three ways to kill cover crops without herbicides:
Winter-killed cover crops for early spring food crops
Mow-killed cover crops.
Roll-killing (but it usually requires special equipment).
We have had one year in 10 as a no-till year. We use no-till cover crops before Roma paste tomatoes, which are transplanted in early May. We don’t need early-ripening for these, making them a good no-till food crop. The soil under no-till cover crops stays colder than tilled soil, slowing the plant growth down.
Late-spring transplanted crops such as late tomatoes, peppers, eggplant, Halloween pumpkins, or successions of cucumbers and squash can do very well after a winter-hardy legume-grass mix no-till cover crop.
To be an effective mulch, you need to get a thick sturdy stand of cover crops, which means sowing in plenty of time, and being generous with the seed. To make the timing work, you need a previous food crop that finishes before the sowing date 4-5 weeks before the average frost (that’s September 7-14 for us).
Timing is also critical in the spring. For maximum N, the legumes in the mix will be flowering right when you need to plant the food crop. Mow the cover crop mix close to the ground, and plant right into the stubble. Transplants or big seeded crops work well. The ground will be relatively hard – you probably can’t make a furrow for small seeds).
It’s not all over with the weed-prevention after that. In our humid climate the no-till mulch biodegrades after 6-10 weeks. In July we roll hay between the rows, to top up the mulch.
Good tools for small-scale no-till work are hard to find. This Haraka Planter has the possibility of providing a breakthrough, so although I don’t have much experience of it, I’m spreading the information. I hope those who buy one and try it will leave a comment. [I’m not receiving any commission if you do buy one.]
The Haraka planter is a very sturdy South African punch planter made for small-scale farmers. Built in Africa for African farmers, and now also available in the US.
It is made by Eden Equipment, and is used for large seeds such as corn, beans, peas, sorghum, soybeans, sunflower. It has a set of thick plastic plates for various seed sizes. We used the smallest hole size for Kandy Korn sweet corn (a fairly small-seeded variety). That gives you some idea of which seeds it can handle. Okra would work, I feel pretty sure. If sorghum and sunflowers work, how about squash, cucumbers and melons?
It can be used on tilled or no-till plots. It can punch through crop debris and plastic mulch very effectively. [Be careful – I tried loading one into the back of a car with two flattened cardboard boxes protecting the seat. It punched right through the cardboard!] On their website there is a video and a link to a flyer. They claim it is the fastest manual planter available. It certainly makes steady progress, as you’ll see in the video. You can plant 1 hectare in 10 hours.
It does take some serious pushing – we tested it first in tilled soil and that was harder work than the soil which had not been recently tilled. See the video to understand the punching and hole-opening action of the sturdy points on the wheel.
You can add a draft animal or a second person pulling, to share the work, if very tough going. You can make and add concrete weights to improve soil penetration in situations with a lot of straw, or packed soil. You can see those in the photo below
The planter comes with an assembly manual that is fairly straight-forward. It uses black and white photos rather than diagrams, so it is a bit hard at a couple of points to determine what to do. I called in someone who already uses one to show me the two bits I was not understanding.
There is a planting mode and a traveling mode, where you flip the heavy tool over and run it on the packing wheel without engaging the planter moving punches. I was struggling to flip the tool over, but my farming friend showed me a way to flip it over sideways, rather than the end-over method I understood from the manual. Later I saw in this video one of the operators push it with his foot to start the flipping action and that was helpful.
In-row spacing: 300mm (fixed) (11.8”). You can make two passes, offset by 6” for closer spacing.)
Eden Equipment also makes a Haraka fine seeder, which I have not seen. It is made for large scale vegetable gardens and small farms, and works in cultivated soil, not for no-till. You can download their flyer from the website. There’s also a video and lots of photos. Like the punch planter, it has a large steel wheel.
Planting depth: 0-20 mm (0.8”), adjustable
Calibration method: kg/ha (no seed spacing)
Seed: grass, small grains, Lucerne (alfalfa), radish, carrot, onion, etc.
For USA sales of both planters, contact Ben Johnston in Montevallo, Birmingham AL
Generally, corn needs cultivating (hoeing and weeding) at least twice, once two weeks after sowing, and once at four weeks. Even better are four cultivations: one at 7 days, a second at 14, a third around 21 days (when the plants are 6-12” (15-30cm) tall) and finally one around 35 days when they are 18-20” (45-50cm) high. We use a walk-behind tiller, and follow up with hoeing and thinning. A wheel hoe can be a useful tool. After about 30 days, corn plants get too big to get machinery between the rows.
At tight spacing, adequate irrigation becomes more important. Never allow soil in corn plantings to dry out. More than 1” (2.5cm) per week may be needed for maximum productivity, although corn is more drought tolerant than some crops. The most important times for watering are silking (when the silks first become visible outside the husks) and ear-filling.
There used to be a belief that it helped production to remove the suckers that came from the base of the plant. This idea has been tested, and that practice has been found to damage plants and possibly even reduce yields. (Reports from Clemson in 2002 and Colorado State in 2004).
No-till planting into strips tilled in a white clover living mulch sounds good but has been found tricky, especially during the grower’s learning curve. Jeanine Davis addresses this in NCSU’s Organic Sweet Corn Production. The clover may out-compete the corn, becoming invasive and hard to get rid of. Soil temperatures will be lower (a disadvantage in spring) and slugs and rodents may abound.
More successful is sowing a cover crop into the corn at the last cultivation, 28-35 days after emergence. We undersow with soybeans (oats and soybeans for our last planting). Although they don’t supply the highest amount of nitrogen, compared to other legumes, they are cheap, quick, somewhat shade tolerant and can withstand the foot traffic during harvesting. Other growers sow forage brassicas. Research has shown that this does not depress corn yields. The brassicas can be harvested for forage after the sweet corn harvest is finished. Undersowing with white clover is also possible.
Succession Planting of Sweet Corn
In order to have a continuous supply of sweet corn all summer, a bit of planning and record-keeping is called for so that each year’s plan can be fine-tuned. The easy and approximate method of getting a good supply is to sow more corn when the previous sowing has 3-4 leaves, or is 1-2” (2.5-5cm) tall. That will be about every two weeks. For a more even supply, sow several different varieties, with differing days to maturity, on the same date. We sow Bodacious (77 days), Kandy Korn (89 days) and Silver Queen (96 days) on the same day, and get over two weeks of harvests.
For fine-tuning for the most even supply, nothing beats real information about what happened, written at the time it happened. We have a Planting Schedule on a clipboard in the shed, and we write down actual sowing dates (next to the planned sowing date), and harvest start and finish dates. Having graphs of sowing and harvest dates for each crop has been very useful for planning effective planting dates. Use the Succession Planting method to calculate best planting dates and intervals for a continuous supply. We make six plantings: 4/26, 5/19, 6/6, 6/24, 7/7 and 7/16, to provide fresh eating every two weeks. The planting intervals are 23, 18, 18, 13, and 9 days. Because we plant three varieties, new corn comes in three times during each two weeks.
To calculate the last worthwhile sowing date, add the number of days to maturity and the length of the harvest window (7-14 days), and subtract this number from your average first frost date. For our 10/14 frost date, using an 80 day corn as an example, 80+7=87 days, brings us back to July 19 for our final sowing date. In practice, because corn matures faster in summer than in spring, this calculation gives you a little wiggle room in case the first frost is earlier than average. You could add a little more wiggle-room to be more sure. We make our last sowing on July 16.
Fast-Maturing Sweet Corn Varieties
Early Maturing Sh2 Varieties: The Supersweet corn varieties are where most of the attention goes these days, and bicolor is preferred. In order of maturity (speediness in ripening): Catalyst XR (bicolor, 66days); Sweetness synergistic (bicolor, 68d); Kickoff XR (bicolor, 69d); Temptress synergistic (bicolor, 70d); Xtra-Tender 2171 (bicolor, 71 d); Nicole (white, 72d); Xtra-tender 20173 (bicolor, 73d); Signature XR (bicolor, 73d); Anthem XR (bicolor, 74d); Natural Sweet Organic (bicolor, 74d); Xtra-tender 3473 (white, 75d); SS2742 (Bicolor, 75d)
Early Maturing SU Varieties: Among yellow SU cultivars, Earlivee is the earliest to mature, at 58 days, and Seneca Horizon matures in 65 days. Sugar Pearl at 73d is the earliest white cultivar to mature. Quickie, at 64 days, Double Standard (OP, 73d) and Butter and Sugar at 73 d, are the earliest bicolor cultivars to mature.
Early Maturing SE Varieties: Among yellow SE varieties, Precocious and Spring Treat mature earliest, at 66 and 67 days, respectively. Bodacious (yellow, 75d) is well worth the wait! Of white varieties, Spring Snow, at 65 days, is the earliest to mature. There are no bicolor SE varieties.
Remember, if you decide to grow several kinds, not to mix sh2 kinds with anything else, or everything will taste starchy.
Sweet Corn Season Extension
Transplanting can provide an earlier harvest, as already mentioned. Clear plastic mulch is sometimes used to increase soil temperature and germination rate, and to conserve moisture, producing earlier maturing corn. The plastic is spread over the seeded beds and slit when the seedlings emerge. It can be cut and removed 30 days after emergence. Weed-free seed beds are needed for this method to work organically, and plastics disposal is an issue. Rowcover is another way to warm soils (and keep birds off).
Pests and Diseases of Sweet Corn
Crows and other birds can be troublesome, removing the seed before it even grows. We leave the row-marking ropes in place (when hand sowing), or put some sticks and string in after machine sowing. Bird-scaring flash-tape may be even more effective. Rowcover would also work.
Some say interplanting corn with big vining squashes deters raccoons and other critters, but I think it deters crew too!
There are several caterpillar pests. An integrated organic approach to keeping pest numbers below economically damaging levels includes crop rotations, tillage, choosing resistant or tolerant varieties, encouraging beneficial insects, and ensuring adequate fertility and water. The next step is to scout for pests regularly, and take action as required.
Corn Ear Worm (CEW) is the most common pest. There may be six generations a year in the South. These caterpillars can bite – it’s just a nip, but can be a shock! A first line of defense is to choose varieties with tighter husks, which are harder for the worms to get into (Bodacious, Tuxedo, Silver Queen). Natural predators can be encouraged by planting alyssum or other small, open-flowered plants. You could buy Trichogramma wasps. The Zea-later was a tool developed for applying vegetable oil in the tip of each ear, mixed with Bt, 2-3 days past the full-brush stage of silking. Unfortunately the treatment caused pollination problems and so it has fallen out of use. If pest numbers are not too high, you can simply cut or snap the ends off the ears.
European Corn Borer (ECB) drills through the whorl of leaves of the young plants, leaving a pattern of large holes as the plant develops. Bt and Spinosad will kill these, as will Trichogramma wasps. To reduce damage in future years, be sure to mow and disk old corn stalks into the soil at the first opportunity. Organically farmed soils have less of a problem with ECB.
Fall Army Worms (FAW) are also killed by Bt and Spinosad. These three pests (CEW, ECB, FAW) can be monitored in a single program, starting when the corn plants are at the whorl stage. At that point, scout for FAW, and treat if more than 15% of your plants are infested. At the pre-tassel and tassel stage scout for ECB and FAW. If infestation exceeds 15%, make a foliar spray with Bt or Spinosad. Check again in a week and repeat if needed. Then at the early silk stage, look for CEW and if needed, inject oil in the tips. If you also see ECB moths, apply Bt or Spinosad.
Cutworm can be a problem following sod, or if there are adjacent grassy areas. Bait them with bran, cornmeal or hardwood sawdust mixed with molasses and water – these baits swell inside the pests and kill them.
Corn Rootworms are best controlled by rigorous rotations.
Corn Smut fungus (Ustilago maydis), known in Mexico as Huitlacoche, is edible at the stage when the galls are firm and tender. The flavor is sweetish. Silver Queen is the variety “best” at producing this fungus, should you wish to grow it. We carefully harvest the infected ears (or pieces of stem) into a special Smut Bucket, trying not to scatter the spores. Because none of us like this delicacy, we take it to the compost pile.
Sweet Corn Harvest
Harvest corn before daybreak for best flavor, because the sugars manufactured in the plant the day before become concentrated during the night. We’re not that dedicated. We harvest ours in the morning, and hurry it to the walk-in cooler.
Harvest may start 18-24 days after half the ear silks show, if the weather has been reasonably warm. Judging corn’s ripeness is a skill, based on information from many of the senses. The first sign we look for is brown dead silks. If the ear has passed that test, we investigate further. All ears should look and feel plump and rounded to the tip. Each variety is a little different, so close attention is needed. Some varieties exhibit “flagging” of the ear, meaning it leans away from the stalk as it matures and gets heavier. New crew can test for ripeness by opening the side of the husk with thumb nails, and puncturing a kernel: the kernels should look filled-out and squarish, not round and pearly; the juice should be milky, not watery or doughy. The advantage of opening the side of the husks is that it is possible to close the gap if the ear is not ripe, without risk of collecting dew or rainfall. If the ear is ripe, we bend it downwards, give it a quarter-turn twist, and then pull up away from the plant.
We harvest every other day, which balances getting the amount we need with not spending more time than needed picking. Such a schedule can work well for CSA farms. Other growers could well need to harvest every day, if daily fresh corn is what your market needs. Leaving a three-day gap risks poor quality starchy ears and a lower total yield.
Take steps to keep the crop cool while harvesting. Never leave buckets of corn out in the sun. Even at room temperature, harvested OP ears lose half their sweetness in 24 hours.
After harvest, cool the corn quickly. Hydrocool if you have a large operation: drench or immerse the crop in near-freezing water. Otherwise, simply refrigerate and keep the corn cool until it reaches the consumer.
Some of this information comes from my book, Sustainable Market Farming.
The No-Till Grower’s Guide to Ecological Market Gardening, by Jesse Frost, Chelsea Green Publishers, July 2021. 304 pages, $29.95
Jesse Frost, the host of Farmer Jesse’s No-Till Market Garden Podcast, has now made a lovely how-to and why-to book for us. No longer do we need to imagine the pictures while listening to the podcasts! The book is generously illustrated with color photos, charts, and diagrams and also hand drawings by Jesse’s wife Hannah Crabtree. The text and photos make plain the experience behind the suggestions. A glance at the bibliography shows how deeply Jesse educated himself on soil biology, chemistry and physics – it’s a list of detailed articles, not a list of books. I was interviewed by Jesse’s collaborator Josh Sattin for Farmer Jesse’s podcast, in November 2019.
Jesse and Hannah farm at Rough Draft Farmstead in central Kentucky, winter hardiness zone 6b with 55” (140 cm) of annual rain on average. While writing the book, Hannah and Jesse moved farms, gaining road frontage for on-farm sales!
The book revolves on three basic principles of professional no-till market gardening: disturbing the soil as little as possible, keeping soil covered as much as possible, and keeping it planted as much as possible. The phrase “as possible” in each of the three principles remind us to be reasonable, and aware of the context. No-dogma is as important as no-soil-disturbance. Sometimes a short-term soil disturbance will ultimately create a healthier soil: you might need to incorporate compost or amendments, or break up compaction. We are not feeding the plants. Nor the soil. We are farming the micro-livestock.
Appendices include notes on cover crops (when to sow, what to pair each cover crop with and how to terminate it); valuable material on critical periods of competition (for weeds or interplanting); resources and chapter notes from world-wide sources.
The topics have been carefully teased apart and the chapters are digestible by busy farmers during the growing season. No need to wait until winter! There are things you can do in midseason to head in the direction of less tilling and more soil-nurturing.
The first section, “Disturb as Little as Possible” includes a fine primer on the science of living soil. (Now you can explain photosynthesis to an inquisitive child.) Don’t skip over this basic soil science. Understanding is the key to good stewardship. The carbon cycle includes plants absorbing carbon dioxide, making root exudates that stream out into the soil, where they feed microbes, which respire most of it back into the air. The plants are not sequestering carbon, as we might wistfully hope in these days of an overheating planet. They are cycling it. It is true that some of the carbon that plants pass into the soil does remain there, in the tissue and exoskeletons of dead organisms, especially when there is no tillage. Some carbon converts to a stable form holding soil particles together.
Most growers probably know that frequent rototilling damages the soil (especially at the same depth every time, or when the soil is too wet or too dry). Soil care can include disturbance of various human kinds. Silage tarps can cause compaction when they gather rain, snow or ice, and stay in place a long time. Microplastic particles can crumble off old tarps into the soil, where they can be eaten up by the microfauna. Polyethylene can prevent beneficial gas exchange between the soil and the air. The soil life also “disturbs” the soil, churning it. Be guided by your observations of your soil, not by a particular belief in a certain method.
The chapter on breaking new ground describes several ways to make a no-till garden from a lawn, pasture or old garden. Deal with any soil compaction up front, either mechanically, or with an extra growing season and big-rooted plants.
Start with the no-till methods Jesse and Hannah use most often. “Shallow compost mulching” involves keeping a 4” (10 cm) layer (not deeper) on bed surfaces year-round, topping up as needed. With a 4” layer, the roots can reach the soil quite soon. Their second preferred method is grown-in-place mulch. Terminate a thick stand of cover crop and plant into the mulch as soon as it has wilted down.
If you don’t need to till before starting your vegetables, you can mow at soil level, and cover with a tarp for two summer months or 3-5 winter months. If you are mowing in the fall, you could spread cardboard and compost to form the beds, then tarp everything until spring.
Silage tarps and plastic mulches can be particularly helpful during transition, to salvage beds when things go wrong, or as emergency tools when a mulch supply line collapses.
The second section, “Keep it Covered as Much as Possible”, discusses compost, mulch, cover crops, flipping beds (transitioning from one crop to the next) and path management.
Composts come in four types (recipes included):compost
Inoculating composts are expensive, fine textured and biologically active. Vermicast (worm manure) is one example. Good for compost tea.
Fertilizing composts such as composted poultry manure are fine textured nitrogen sources to use before planting.
Nutritional composts supply organic matter, microbiology, nutrients, minerals, and ample amounts of carbonaceous material. They can be used in larger amounts.
Mulching composts are high in carbon, maybe 20 C:1 N, and relatively low in nutrients.
Mulching retains moisture, prevents compaction, reduces weeds, provides habitat, provides foods for some creatures, and reduces the impact of heavy rain or heavy feet. Straw can be expensive. Hay gives better weed suppression, but may itself be a source of weed seed. Spoiled hay has fewer live seeds, comes at a better price, and is messier to spread. Hay is more nutritious for the soil than straw. You could solarize your hay bales for 3-8 weeks before spreading, to kill seeds.
Paper and cardboard give excellent occultation compared to loose straw and hay, and provide an effective mulch with less depth (easier for transplanting into).
Wood chips, sawdust and bark mulch can sometimes be free, from workers clearing under power lines. Tree leaves and leaf mold are nutritious materials for mulch or in compost. Cover crops may be mowed or crimped to kill them, usually leaving them in place as a newly-dead mulch.
Peat moss is controversial. Peat bogs are very effective carbon sequestering habitats, and based on this, we should not use peat without restoring the bogs. Coconut coir is sometimes used as an alternative to peat moss, but we are mining the thin tropical soils when we import it.
Plastic mulches stop weeds, warm the soil, and conserve moisture. Landscape fabric is durable, and some growers burn holes for transplanting certain crops, and reuse it many times. Organic regulations require plastic mulch to be taken up at the end of the growing season, and they do not accept biodegradable plastic mulches.
Chapter Five is about flipping beds (replacing one crop with the next). Chopping plants off at the surface and/or tarping are two main no-till methods.
Jesse provides a valuable table of no-till crop termination methods for 48 vegetables and herbs. Whenever possible, leave the crop roots in the soil. Some can be cut at the surface (lettuce, baby greens, cucurbits and nightshades), some need to be cut slightly below the surface (brassicas, beans, corn, spinach and chard) and most others are harvested as root crops. Roots are a valuable source of carbon and root exudates, and help air and water pass through the soil.
Flail mowers, weed whackers (with a bush blade rather than a nylon line), scythes, hoes and knives can all be used to cut down old crops, depending on the particulars. When a crop is terrminated, deal with soil compaction if needed, amend the soil, keep it damp, get mulch in place, and replant the same day if you can, to help preserve microbes. If the previous crop was a cover crop, your fertility is supplied by that, and no more amendments are likely needed.
Tarping (introduced into English by Jean-Martin Fortieras “occultation”) is an effective no-till method. Silage tarps can kill crop residues, warm the soil and germinate weed seeds, which then die in the dark. Prepare an area by mowing it close – it is important that the tarp is in close contact with the soil, to break the plant matter down quickly. Tarps need to be well battened down. Jesse tells us that 2600 square feet (242 m2) is about as big a piece as any one person will want to move. Say, a 25 x 100ft (8 x 30 m) piece.
Leave tarps in place for two summer weeks, 3-4 weeks in spring and fall, and two months or more in winter. Avoid PVC tarps (contain endocrine-disrupting phthalates), be wary of polyethylene (may contain phthalates), but woven landscape fabrics are made from polypropylene, which does not contain phthalates.
Solarizing is a similar technique using clear plastic to heat the soil, kill weed seeds, disease organisms and crop residues. Bryan O’Hara in No-Till Intensive Vegetable Culture has popularized using old hoophouse plastic. Solarizing can produce temperatures of 125˚F (50˚C) compared with 110˚F (43˚C) under tarps. You may need only 1-3 sunny days to kill crop residues with solarization. Cover crops take about 7 days. The heat will not go deep in that time: more of the soil life will survive than with tarping. Good edge securing is vital for success.
The necessary (but less profitable) task of path management is next. The goal is to make pathways do work, retaining moisture, housing microbes, and generally contributing to a healthy environment. The first priority is to get rid of weeds.
Wood chips and sawdust can perform well as path mulches. Sawdust mats down into an effective weed-preventing layer, and 2” (5 cm) is often enough. Get sawdust in place ahead of leafy greens, so that it doesn’t blow into the crop.
Living pathways sound wonderful, but can be very challenging, and it’s best to start with a small trial. Choose a non-spreading grass or a mix of clovers, grasses and herbs. Mow every week until the path plants stop growing.
Another option is to grow cover crops in the paths, mow-kill or winter-kill them and leave the mulch in place. Timing is critical. The crop needs to be planted and harvested either before the cover cop grows very tall or after it is dead.
Section three, “Keep it Planted as Much as Possible” has three chapters: fertility management, transplanting and interplanting, and a gallery of no-till crops, pulling together various materials and methods.
Test soil organic matter each year. Jesse points out that although organic matter is largely dead organic materials, a truly living soil must contain a fair amount of it! 5-10% OM is a healthy percentage; more is not better. OM above 12% can cause water retention problems and poor aggregation. Seedlings can struggle to germinate and establish.
You can improve soil performance with compost, mulches, cover crops, gypsum for clay soils, and cultivated indigenous microorganisms (as in Korean Natural Farming). Use good inoculating compost or compost tea in the root zone. Microbes aggregate the soil into various sizes of crumbs, improving the soil structure.
Be careful using perennial cover crops as living mulch around cash crops – the yield is almost always reduced, and sometimes the quality is compromised too.
If you are running a compact commercial market garden, growing cover crops may be out of the question, and you will rely on outside inputs. With a slightly bigger plot you can grow cover crops before long-season food crops, and use outside inputs for intensive short-term crops. Larger farms may find cover cropping more efficient than large-scale mulching. Winter-kill, classically with oats and spring peas sown in late summer, will provide a light mulch for early spring crops.
Cover crops can be terminated by crimping at the milk stage and tarping. Jesse shows a crimping tool made from a bed-width board with a foot-sized metal hoop at each end and a string or rod as a handle. This is a variation on the T-post tool advocated by Daniel Mays in The No-Till Organic Vegetable Farm.
Crimping and tarping gives more flexibility on timing than does crimping alone. Crimping and solarizing can be even quicker. Crimping or mowing, then topping with cardboard and mulch compost is another method, if you have sufficient supplies. Plant a shallow-rooted crop in the compost layer, don’t bust through the cardboard unless you have let the cover crop die for a few days before covering.
For side-dressing long-season crops, Jesse uses the EarthWay seeder with the pea plate. This never occurred to me! Another surprise suggestion was to use silage tarps white side up, to germinate carrots in the summer! Check daily, and remove the tarp late in the day to save the tender seedlings from frying in the mid-day sun.
Interplanting is best approached cautiously, with small trials and good notetaking. Interplanting can cause lower yields and poorer plant health when combinations and timing are wrong. Measure yields and weigh the costs and benefits. Popping lettuces into random lettuce-sized gaps rarely goes wrong, and you might keep a tray of lettuce transplants handy at all times.
Peppers take 60-70 days before bringing in any money. If you plant an understory of lettuce, you can generate income much sooner, and the lettuce will be gone before the peppers need the space. Growing two crops together reduces the impact of a crop failure, and makes unprofitable crops more worthwhile.
Read about the critical period of weed control, when crops are most affected by competition from weeds, sister seedlings or an intercrop. Like other good mentors, Jesse is quite open about his mistakes. Don’t confuse tall plants with healthy high-yielding plants! They may be striving for better light. Seedlings suffer more than transplants from being out-shaded. Transplants are past perhaps half of their critical weed-free period before you even set them out.
Relay cropping is a method of adding in another crop after the first is established but before it is harvested. A sure-fire way of keeping living roots in the ground! With careful planning you can sometimes run a multi-crop relay sequence.
To implant these ideas firmly in our minds, Jesse discusses seven example crops, including varieties, seed quantities, bed prep, weed control, seeder, spacing, pest control, harvest, yield, intercrops, marketing, tips, and notable failures (no need to make the same mistakes!). The examples (carrots, arugula, garlic, lettuce, sweet potatoes, beets, and cherry tomatoes) can be extrapolated for almost anything else. I took notes: there’s always good tips to be learned from other growers. Buy the book, you’ll quickly save the price! And more of your growing can succeed!
I originally wrote this review for the upcoming June/July 2021 issue of Growing for Market magazine.
Root Crops to Plant in Central Virginia in February
We sow no root crops in our hoophouse in February. It’s too late for radishes or turnips. If you are in a place colder or darker than winter-hardiness subzone Zone 7a, with an average minimum temperature of 0° to 5° F (-18°C to -15°C), see Root Crops in January.
If the soil outdoors is dry enough and not frozen, we spread compost on the raised beds we plan to plant in February and March, and till in the compost. Root crops that we sow outdoors here in February include carrots #1 and turnips in mid-February, and carrots #2 and radishes in late February. It’s true not much growing happens in February, but it helps us if we are able to get some crops planted early, leaving us more capacity for other crops once those are in the ground. And if the soil isn’t dry enough, we just do those jobs as soon as we can. We would hate to miss an opportunity!
Carrot Bed Prep
Carrots do very poorly with competition from weeds or too many other carrots. You can make use of the Stale Seedbed Technique, preparing the bed ahead of time, and flaming or hoeing one or more flushes of weeds as they germinate. I’ll do a separate blogpost on flame-weeding soon, as I have too much info to squeeze in here. It works so well, it feels like cheating!
Carrots are small seeds, needing a fine tilth (small soil particle size and good texture – not likely to crust or blow away).Good information on crop spacing for maximum yields, or biggest vegetables is in an out of print book, The Complete Know and Grow Vegetables by JKA Bleasdale, PJ Salter, and others. For maximum total yield of carrots, they recommend 1.5” x 6” (4 x 15cm). You get medium sized carrots. For early carrots go with 4 x 6” (10 x 15cm) to minimize competition and get rapid growth. If you want to have rows more than 6” (15cm) apart, calculate the area of these optimum spacings, then divide by your chosen row space. For example, if your rows are 12” (30cm) apart, the carrots can be as close as 0.75’ (2cm) if total yield is more important than individual size, or 2” (5cm) for fast early carrots. We do five rows in a 4 ft (1.2m) bed, so the rows are about 10” apart, with the outer rows 4” (10cm) from the bed edge.
Carrot Thinning and Weeding
Remember to thin carrots as soon as you can see them well enough to do so. We usually hoe between the rows first, then crawl along thinning and weeding. It does take time! But you won’t get good carrots without thinning, unless you either have a precision-seeder that drops one seed per inch, or pelleted seed which you can sow at one per inch. Precision seeders like the Jang are expensive, but worthwhile if you need to use it every week. Pelleted seed costs more than raw seed, and its big advantage is traded off for two other disadvantages: The soil has to be kept well-watered until germination or else the clay coating will imprison the seed forever, and the seed does not store for long – don’t keep any over for next year.
Greenhouse Root Crop Sowings for Transplants
The only root crops we ever transplant are celeriac and kohlrabi (a stem vegetable really, not a root). I have transplanted many things and I am skeptical of books saying this or that can’t be transplanted, but not beets or rutabagas, which I hear people transplant as soil blocks or plugs. So try it if you think it will help.
We have grown both Diamante (100 days from transplanting) and Large Smooth Prague (110d), and strongly prefer Diamante, as it seems to us to be more tolerant of warm weather, less prone to rot, and easier to clean. Several growers say that Diamante and Brilliant are virtually indistinguishable.
This crop likes rich soil with lots of organic matter, some shade from mid-day and afternoon sun, and ample water without sitting in waterlogged soil. We make sure to choose beds in a shadier part of the garden. Celeriac can rot if too damp, so keep it weeded and remove some of the lower leaves to improve airflow. A pH 5.8-6.7 is ideal. Celeriac can benefit from seaweed as a foliar spray, or side-dressing with compost during the long growing season.
Celeriac requires long steady growth, and the challenge is to prevent checks to growth. The Virginia climate is on the warm side for celeriac, it prefers cooler areas, but we have good success if we pay attention at a few critical times. Celeriac can tolerate frost quite well, so there is no hurry to harvest in the fall.
Sow seeds 1/8″(3mm) deep, and keep the soil surface moist. The minimum germination temperature is 40°F/5°C, and the optimal range 59–70°F/15-21°C. Germination is slow, typically 14 to 21 days, and it takes 10-12 weeks to grow to transplant size, so start in plenty of time. We sow in open flats, then spot out (prick out) into deeper flats. We sow February 10, which is about 10 weeks before our last frost date. Celeriac can be sown from 67 days before the last frost date to 184 days before the first fall frost date, but you don’t get large roots unless you have plenty of growing time.. If your climate includes long chilly springs, I’d suggest starting 12 weeks before the last frost date.
Emergence takes at least 12 days at 59°F/15°C and 7 days at 68°F/20°C. The ideal temperature is 68°F/20°C day, and 59°F/15°C at night. The fluctuating temperatures, with nights cooler than days by 9°F/5°C, help speed germination. Another factor when choosing germination temperature to aim for, is that at 59°F/15°C, only 40% of the seeds produce seedlings, compared to 97% at 68°F/20°C.
Celeriac should not be hardened off by reducing temperatures, as that can cause them to bolt. More than about 9 night temperatures below 55°F/12°C will cause bolting. Plants can have their watering reduced to help them get ready for the big outdoors. Use rowcovers if a cold spell arrives after you have planted them out, or if you know cold weather is likely to return. Falling apple blossom is a phenology sign that conditions are suitable.
Kohlrabi is very easy to grow, treat it just like cabbage or kale.
It can be direct-seeded, but for an early crop, especially if you live in a climate like ours where spring turns into summer very quickly, use transplants. We don’t grow a lot, only 180 feet (55m) in total for 100 people. We also grow kohlrabi in the fall, transplanting bare root transplants from nursery seedbeds around August 3. We grow twice as much in fall as spring, because we can store them for winter.
We have grown both Early White Vienna and Early Purple Vienna. Growing both provides for pretty harvests. We sow February 8 at 4 seeds/inch (0.5 cm apart) in open seed flats, aiming to have the plants spotted out, hardened off and transplanted outdoors with rowcover on March 13. Fast work!
Root Crops to Harvest in Central Virginia in February
As for January, in central Virginia, there are normally no roots that we could be harvesting outdoors in February except parsnips, Jerusalem artichokes and horseradish. We do have horseradish, but not the others. Of course, you can only dig up root crops if the ground is not frozen!
We have had outdoor night temperatures of 16°F/-9°C and 12°F/-11°C. This winter we have some carrots “growing” in the fresh air and some late-sown beets under rowcover. I don’t think we’ll get roots from the beets, but the leaves might make a nice change from brassicas as cooking greens.
In the hoophouse our radishes #3 (sown October 30) will come to an end by 2/1. Our #4 radishes will get harvested this month. Our #5 radishes, sown 12/23, will feed us from then until around April 7
We still have some of our first turnips (sown around October 13) until mid-February, and they have reached a really good size, thanks to early thinning. This month we can harvest the second sowing (October 25). We thinned turnips #2 in early January. They are looking good too.
We have not yet needed to unroll our inner rowcovers in the hoophouse. We wait until we expect it to get down to 8°F (-13°C) outdoors, as we like to avoid extra work!
Other Root Crop Tasks in Central Virginia in February
Check stored vegetables
Stored crops need to be checked for decay at least once a month, preferably once a week now the days are getting longer and the temperatures will get warmer. From storage, we can eat beets, carrots, celeriac, kohlrabi, parsnips, potatoes, rutabagas, sweet potatoes, and turnips, if we grew them.
Special Root Crop Topic for February in Central Virginia
Wrap up the winter planning
Our garden planning wraps up by mid-February, with all the budgets, crew selection and shift decisions (afternoons in cold weather, mornings in hot weather –we’re mostly half-day gardeners, with one or two stalwart all-day workers)
Order summer cover crop seeds
For early spring, if we find an area without a winter cover crop and we realize we won’t plant it with a vegetable crop for at least 8 weeks, we sow oats. They will smother weeds and add organic matter to the soil when you till them in.
If you have not already ordered summer cover crop seeds, this would be a good time to do so. Cover crops suppress weeds, add organic matter, feed the organisms in the soil and attract beneficial insects, birds and amphibians to feed and reproduce. Biodiversity encourages ecological balance that can help reduce plant diseases and pest attacks. Have a goal of No Bare Soil. Seek out odd spaces to fill with cover crops.
Once frosts are past, buckwheat is an easy cover crop. Its flowers attract beneficial insects, and it is a very manageable (not too tall) fast-growing crop. Buckwheat can be in and under in a month.
Just as fast is mustard, but we don’t grow that because it’s a brassica and we grow a lot of brassica food crops. Keeping a good crop rotation is important to us. Also we have harlequin bugs and we don’t want to feed them year round.
Sorghum-sudangrass hybrid is a fantastic, huge warm weather grass type cover crop, but don’t grow it if you have only a lawnmower, a scythe or a nylon line weed whip to cut it down! For smaller scale gardens, choose Japanese millet.
Soybeans, southern peas and sunn hemp are easy legume cover crops for warm weather, providing nitrogen for the next crop.
Cover cropping is a big topic. See my book Sustainable Market Farming for more. Here I’m just pointing you in the right direction enough to order seeds soon. You can read up more later.
There are several aspects of vegetable harvesting. In this post I will look first at maturity indicators, then at four ranges of cold-hardy crops for harvest at various stages of winter, followed by a reminder of the order for harvesting storable crops, according to the coldest temperature they can take. After that I have links to a couple of other websites with great information on these topics, a mention of two articles on seed saving and one on garlic planting I have in Growing for Market magazine. And a link to a Mother Earth News Fair Online workshop on establishing winter cover crops.
Harvest and Maturity Indicators
Don’t harvest too soon or too late. How do you know when it’s ready to harvest? Different factors are important for different crops. Use all your senses.
Size: Cow Horn okra at 5”/13 cm (others shorter), green beans a bit thinner than a pencil, carrots at whatever size you like, 7”/18 cm asparagus, 6”/15 cm zucchini
Color: Garden Peach tomatoes with a pink flush. The “ground spot” of a watermelon turns from greenish white to buttery yellow at maturity, and the curly tendrils where the stem meets the melon to turn brown and dry. For market you may harvest “fruit” crops a bit under-ripe
Shape: cucumbers that are rounded out, not triangular in cross-section, but not blimps. Sugar Ann snap peas get completely round before they reach peak sweetness.
Softness or texture: eggplants that “bounce back” when lightly squeezed, snap beans that are crisp with pliable tips. Harvest most muskmelons when the stem separates easily from the fruit (“Full slip”).
Skin toughness: storage potatoes when the skins don’t rub off, usually two weeks after the tops die, whether naturally or because of mowing.
Sound: watermelons sound like your chest not your head or your belly when thumped. Try the “Scrunch Test” – press down firmly on the melon and listen and feel for the separation of the ripe flesh inside the melon.
Cabbages are fully mature when the head is firm and the outer leaf on the head is curling back. Ignore the separate “wrapper leaves” when making this judgment. If you need to keep mature cabbage in the ground a few days longer, twist the heads to break off some of the feeder roots and limit water uptake, and they will be less likely to split.
Select blue-green broccoli heads and harvest them before the flower buds open, but after they’ve enlarged. We press down with finger-tips and spread our fingers to see if the head is starting to loosen.
Sweet corn will be ready to harvest about three weeks after the first silks appear. Corn is ready when the ears fill to the end with kernels and the silks become brown and dry. An opaque, milky juice will seep out of punctured kernels. You can use your thumbnails to cur through the husk on the side and view the kernels. Don’t make your cut on top of the ear, or the dew and rain will get in and rot the corn.
Garlic is ready to harvest when the sixth leaf down is starting to brown on 50% of the crop. See Ron Engeland’s Growing Great Garlic. Harvesting too early means smaller bulbs (harvesting way too early means an undifferentiated bulb and lots of wrappers that then shrivel up). Harvesting too late means the bulbs may “shatter” or have an exploded look, and not store well.
Cut across hardneck garlic – airspaces around the stem show maturity
Wait until the tops fall over to harvest, then gently dig up the whole plant and dry. Leave the dry, papery outer skin on the onion for protection.
Four Ranges of Cold-Hardy Crops for Harvest at Various Stages of Winter
Crops to keep alive into winter to 22°-15°F (-6°C to -9°C), then harvest. Harvest and use soon: Asian greens, broccoli, cabbage, chard, lettuce, radishes. Harvest and store: beets, cabbage, carrots, celeriac, kohlrabi, winter radish (including daikon), rutabagas, turnips. Many greens and roots can survive some freezing, so it is worth experimenting to find how late you can keep crops outdoors.
Hardy winter-harvest crops: cabbage (Deadon), carrots, collards, kale, leeks, parsnips, scallions, spinach. We grow our winter-harvest crops in our raised bed area, which is more accessible in winter and more suited to small quantities.
Overwinter crops for spring harvests before the main season. Some crops, if kept alive through the winter, will start to grow again with the least hint of spring weather and be harvestable earlier than spring plantings. Depending on your climate, the list can include carrots, chard, chicories such as radicchio and sugarloaf, chives, collards, garlic, garlic scallions, kale, lettuce, multiplier onions (potato onions), scallions, spinach. In mild areas, peas can be fall sown for a spring crop. Sow 1″ (2.5 cm) apart to allow for extra losses.
Winter hoophouse crops: The rate of growth of cold-weather crops is much faster inside a hoophouse than outdoors. The crop quality, especially with leafy greens, is superb. Plants can tolerate lower temperatures than outdoors; they have warmer soil around their roots, and the pleasant daytime conditions in which to recover. Salad greens in a hoophouse can survive nights with outdoor lows of 14°F (–10°C) without inner rowcover.
In my post Root Crops in October, I gave this list of storable crops in the order for harvesting, related to how cold they can survive.
Clear and store (in this order):
Sweet potatoes 50°F (10°C)
“White” Peruvian potatoes 32°F (0°C) approximately
Celeriac 20°F (°C)
Turnips 20°F (°C)
Winter radish 20°F (°C)
Beets 15-20°F (°C)
Kohlrabi, 15°F (°C)
Carrots 12° F (°C)
Parsnips 0°F (°C)
Here are some links to a couple of good sources for more harvest information:
Prepare your garden for colder weather, plant winter crops where there is still time, harvest crops that will suffer from cold, construct low tunnels with rowcover or clear plastic to keep crops somewhat protected from wind and cold temperatures
I have written articles for Growing for Market magazine about growing and saving seeds (August and September issues), and planting garlic (October issue).
Given the shortages of some varieties this spring, it wouldn’t surprise us if more people tried producing seeds of vegetable or flower varieties this year. Here are links to articles from the August and September magazines, covering wet and dry seed processing.
Wet seed processing and saving
Wet seeds are embedded in fruit. Wet processing has four steps: scooping out the seeds or mashing the fruit, fermenting the seed pulp for several days, washing the seeds and removing the pulp and then drying the washed seeds.
Dry seeds develop in pods, husks or ears, and dry on the plant rather than inside a fruit. While you obviously want to get seeds into the hands of growers before they need to plant, and into seed catalogs before they get printed, often there is no urgency to extract the dry-seeded crops from their pods. You can wait for a slower time, or use seed cleaning as a rainy-day job.