Workhorse Crops for June

Farao early cabbage
Photo Pam Dawling

Workhorse Crops for June

I’ve chosen 14 Workhorse Crops (including two pairs) to focus on at the beginning of every month, until April 2022: These are crops that we can rely on under a wide range of conditions. Some Workhorse Crops are easy to grow, some pump out lots of food, some are “insurance crops”, some are especially profitable (for those growing for market), and watermelons are the circus pony among the workhorses, I admit, but we all need fun!

I intend for this series to help growers who want to become more efficient, productive and profitable (if selling) as we emerge from sheltering at home and expand our lives again. Don’t give up growing your own food, just choose some less time-consuming ways to do it.

Our May 5 sowing of bush beans on June 30.
Photo Pam Dawling

Workhorse Crops to Plant in June

June is another busy planting month here in central Virginia. Next month the heat strikes hard, and the daylight starts to get shorter, but this month we are still climbing the hill of the year. Ten of our 14 Workhorse Crops can be planted in June.

Beans: We sow bush beans every few weeks to keep up supplies of tender beautiful beans. See the Special Topic section for info about Succession Planting, to help you determine when and how often to sow beans and other short-lived warm weather crops. Also see the Special Topic section to read how we control Mexican Bean Beetles that used to destroy our bean plantings. Click this link to read about soaking bean seed, using inoculant, sowing through biodegradable plastic mulch using a jig, sowing sunflowers in our bean rows as place-markers when harvesting.

Carrots: I wrote a lot about carrots in the past year, when the monthly series was on root crops. See this post on preparing beds for sowing carrots, and weeding and thinning. Check out this post on flame-weeding, if you plan lots of carrot-growing!

We sow carrots in late February, then twice in March, once a month in April and May and after that we’d like to not sow more until the beginning of August. Carrots grown in hot weather don’t taste that good: there’s little sweetness and too many terpenes (the compound that in small quantities gives carrots their distinctive carrotiness, but can be overpowering if too strong.) But home-grown hot weather carrots are still better than jet-lagged travel-weary carrots from afar. You could use shadecloth over the beds. If we have not grown enough carrots by the end of May to see us through to October, we sow in June, and even July if we must.

Carrots under shade cloth in summer.
Photo Pam Dawling

Chard: The perfect insurance crop! We use chard for fresh greens in summer, when spring kale, collards, broccoli and cabbage have long bolted and been turned under so we can plant something else. We transplant our chard into a hay mulch in late April. Organic mulches help keep the soil cool during hot weather, so are very helpful for leafy greens. This crop will be in the ground until mid-winter, and mulch will keep back most of the weeds.

Chard provides leafy greens all summer whenever you need them, and you can ignore it when you have plenty of other vegetables! As a biennial, chard will not bolt the first year (unless stressed by lack of water).  I’ve noticed the red chards bolt more easily than the green ones. I suppose red crops are a bit stressed already, as they are short of chlorophyll, compared to the green ones, making photosynthesis harder work.

Potatoes: I wrote a special series on potatoes last year. Click the link to access the whole series, starting with planting in April. Here we plant in March and June. For our June-planted potatoes, we pre-sprout the seed potatoes for just two weeks (shoots grow quicker in warm weather than in early spring). To protect the planted potatoes from the summer heat, we hill immediately after planting, even though we can’t see the rows! Then we unroll big round hay bales down the field to cover all the soil. Potato shoots grow strongly, and can make it up through the extra height of the hills/ridges and through the 3” (7.5 cm) of hay. After about 16 days, we walk through the field, investigating spots where there is no sprout. We call this task “Liberating the Trapped Shoots”. Often the problem is just an overthick clump of mulch, and the shoot will be quite literally trapped (and completely white). We simply let he shoot see the light, and redistribute the over-thick mulch.

June-planted potato emerged through hay mulch.
Photo Pam Dawling

Sweet corn: we make 6 sowings of sweet corn, to harvest from July 4 to mid-October. We are well into corn-planting time, which continues until mid-July, when there are not enough warm days left in the season to mature another sowing. Remember: don’t plant a mixture of different corn genotypes, and don’t plant Indian corn, popcorn or any kind of flint or dent corn within 600′ (180 m) of your sweet corn.  This leads to very disappointing starchy corn. We grow only sweet corn in our garden, to avoid this problem.

Sweet potatoes: I wrote a lot about planting sweet potatoes in 2020. Wait for the soil to warm before planting out your sweet potato slips, they don’t grow well if too cold. We plant ours a couple of weeks after the last frost, around the time we transplant peppers and okra. In early June, we replace any casualties, if needed, to fill out the rows again. This year we have a beautiful looking patch, with rows of healthy plants on ridges, with biodegradable plastic mulch. We have a solar-powered electric fence to deter the deer. My latest worry is groundhogs, who can slip right under the electric fence. They haven’t yet, but I expect they will, if we don’t catch them first.

Sweet potatoes on biodegradable plastic mulch, with solar electric fence charger.
Photo Pam Dawling

Tomatoes: In mid-June we plant a bed of late tomatoes, to boost the yields when the maincrop beds start to pass their peak. We planted our main crop tomato beds at the very beginning of May, and they’re looking quite good.

Here’s a post about planting tomatoes in our hoophouse. We use the same techniques in the hoophouse and outdoors. We transplant one row of tomatoes down the centerline of a 4ft (1.2 m) bed, 2ft (60 cm) apart. Once the weather has settled so that we’re confident we won’t need rowcover any more, we stake and stringweave. We install a steel T-post every two plants (4ft /1.2 m) apart and start stringweaving when the plants are about 12ins (30 cm) tall. I’ll say more about stringweaving next month.

Watermelons: As I explained in May, I gave watermelon a “Circus Pony” place among the workhorses! They’re not easy, therefore not reliable, but they provide so much pleasure when they do grow well. We transplant our watermelons, to get ripe ones as early as possible.

Watermelons grow very well on black plastic mulch, which warms the soil as well as keeping weeds at bay. The first year we switched from using hay mulch to biodegradable plastic mulch, we were astounded to get ripe melons a full month earlier!

If you want to use organic mulches for warm weather crops, don’t do it immediately. Wait till the soil warms through. This year we made that mistake, then we had late cold weather and the transplants all died. We’re going to experiment with station-sowing seeds directly in the gaps. Station-sowing is a technique of putting several seeds in the ground at each spot (station) where you want one plant to grow. Rather than making a furrow and sowing a row that needs thinning later. It’s a good technique for remedial work (ahem!), or if growing very expensive seeds, or for crops you are not familiar with, such as parsnips. You see several seedlings all the same and can be pretty sure it’s the thing you planted.

Watermelons can be planted from seeds when the ground has warmed to at least 70°F (21°C). On average, it takes about 85 days for Crimson Sweet seedlings to mature and produce ripe fruit. This is late for us to sow watermelons, and we certainly won’t get early ones this year, but we could get them in September. Better than none.

I described transplanting watermelons last month, if you need that info.

Crimson Sweet watermelon.
Photo Nina Gentle

Winter squash are a true workhorse, and can still be sown here early in June, provided we don’t sow the slow-maturing ones like the gigantic Tahitian Butternut. Aim for harvesting in September and October and count back to see how many days you have until you want to harvest. Then choose the varieties that will have enough time. You can also transplant winter squash if you need to. We did this once when our fields flooded. It worked out fine.

We mostly grow Butternuts, Moschata types that store best. This is the type to focus on if you want squash with no damage from borers or cucumber beetles. The tougher stems are better able to repel invaders. They need warm growing temperatures above 60°F (16°C).

See last month’s post for more about sowing winter squash, and for other kinds of winter squash, such as some Maxima squashes that store quite well and have relatively high resistance to squash bugs compared to others in this group, and Pepo squashes, suitable for storing a few weeks only

A bee pollinating squash.
Photo Pam Dawling

Zucchini (courgettes) and summer squash: another crop type that we succession sow, to get a continuous supply. More about succession planting below in the Special Topic section. We make five or six plantings, each one half yellow squash (Zephyr, Gentry) and half zucchini (TenderGrey, Noche, Golden Glory). We grow our earliest squash in the hoophouse, setting out transplants at the beginning of April. Our first outdoor crop is also from transplants. After that, the soil is warm (60°F/15.5°C) and we direct sow. The time from sowing to harvest is only around 42-54 days.

After transplanting or sowing, we hoop and cover the row with insect netting (rowcover works if it has no big holes). We have many bugs that like these plants, especially the striped cucumber beetles, so we keep the rows covered until female flowers appear. At that point we need the service of the pollinators, unless the squash is parthenocarpic (sets fruit without pollination). We pack away the covers, hoe and thin the squash to 24” (60 cm). It would be better to thin sooner, but we rarely find the time.

Workhorse Crops to Harvest in June

We have mnemonics for harvesting: Monday, Wednesday and Friday might be the crops beginning with the plosive Ps and Bs: peas, beans, beets, broccoli, blueberries etc. Tuesdays, Thursdays and Saturdays would be the crops beginning with the hard K and G sounds: kale, corn, carrots, collards, cabbage, garlic scapes etc.

Other crops like asparagus, lettuce, cucumbers, summer squash and zucchini we harvest 6 days a week. Some, like cabbage, we harvest twice a week.

Asparagus can be harvested here until early in June. Every day for the 8-week harvest period, snap off at ground level all the spears above a certain length. We chose 7” (18 cm). This task is best done first thing in the morning, when the spears are crisp. Daily harvest will also remove asparagus beetle eggs, controlling the pest level.

Cabbage is ready here from late May until mid-July. We store enough to feed us until we start harvesting fall cabbage.  An early sowing of fast-maturing varieties (like Farao or Early Jersey Wakefield which can be ready in only 60 days) can be followed by harvests of slower varieties. When a cabbage is ready for harvest, the head is firm and the outer leaf on the head (not the more horizontal wrapper leaves) will be curling back. For cabbage to store to eat over the summer, cut with a strong knife and set it upside down on the nest of leaves to dry a little. Come back along the row with a net or plastic bag and gather up the storage quality cabbages to refrigerate. Gather any lower quality cabbages to eat soon. If you would like to get another harvest from the same plants, cut criss-cross into the stump. Small “cabbagettes” will grow and can be used raw or cooked. They won’t store.

Carrots can be ready about three months after sowing in spring, although you can get thinnings for salads sooner. Read here about harvesting carrots.

Chard is ready for harvest as soon as you decide the leaves are big enough. Simply snap or cut off some outer leaves and stand them in a bucket with a little water until you cook them. For a sustainable rate of harvesting with chard, always leave at least 6 of the inner leaves to grow.

Garlic harvest time will be soon if not already. I wrote about garlic last week.

Kale and collards can be harvested until they are bolting, as long as the flavor is acceptable. Our spring-planted ones are not bolting yet, but the fall-planted ones were tilled in a couple of weeks ago.

New potatoes could be dug here during June, if you don’t mind reducing the final yield. The flavor of new potatoes, with their delicate skins, is very special. As a child, I ate them boiled with mint, and topped with some butter.

Tomatoes start to ripen this month. Our hoophouse tomatoes have started to yield a small amount of Glacier, Stupice, Sungold and Amy’s Apricot.

 

Zucchini harvest.
Photo Brittany Lewis

Zucchini and summer squash are ready from the hoophouse early sowing since about May 20.  We are now (June 2) harvesting our first planting of outdoors. We harvest every day to the fall frost (or beyond if we remember to cover that last planting with rowcover on chilly nights.).

From storage: carrots, potatoes,

 Workhorse Crops Special Topic:

Succession planting, and Mexican bean beetles

Succession planting is a topic I have often presented at workshops, so rather than give you more words, I’m giving you the slideshow from 2019. Towards the end it includes information about dealing with Mexican bean beetles.

 

 

 

Garlic Almanac and Phenotypic Plasticity

Silverwhite Silverskin garlic
Photo Southern Exposure Seed Exchange

Garlic Almanac and Phenotypic Plasticity

(How garlic adapts to its locality)

It’s garlic harvest season for many of us and I notice many growers are searching my site for information. Here are quick links.

Garlic signs of maturity from October 2020

Everything You Need to Know About Garlic includes all the links listed below here.

Much about garlic is to be found in my Alliums for the Month Series:

Garlic harvest.
Photo Twin Oaks Community
Other posts about garlic, starting with harvest:
Pulling garlic scapes.
Photo Wren Vile

Phenotypic Plasticity

Phenotypic plasticity of garlic refers to the changes to a garlic variety grown in a particular location. Genetically identical garlics can grow differently in different environments. Garlic reproduces asexually, the new cloves are all clones of the mother plant, with no new genetic material introduced. And yet, over time, garlic saved and regrown each year in a certain locality will adapt itself to that location, due to the particular soil type, water availability, local temperatures, latitude, altitude and cultural practices. For example, studies have shown that varieties grown in drought-prone areas can, over years, develop more drought-tolerance. Commercial cultivars can have the highest bulb yield under well-watered conditions, but drought will show up the adapted strains in a comparison trial.

Garlic Plants
Photo credit Kathryn Simmons

We have been growing our own strain of hardneck garlic for over 30 years, and it does really well here. Originally the seed stock was a bag of garlic from the wholesale vegetable market. This is the very thing we are told not to do, as it may introduce pests and diseases. Indeed, it may, but our original folly is now deep in the past, and we have fortunately seen no problem.

I was reminded about phenotypic plasticity, when a friend and neighboring grower reported that the seed garlic we had passed on to her was doing well and was mature a couple of weeks before the variety she normally grows.

From the 2004 work of Gayle Volk et al, Garlic Seed Foundation analyzing 211 garlic accessions, we have learned that there are many fewer genetically distinct varieties of garlic than there are named varieties. Of the 211 accessions in that trial, only 43 had unique genotypes. But garlic shows high biodiversity and ability to adapt to its environment. The same garlic genotypes in different environmental conditions can show different phenotypes. This demonstrates the high phenotypic plasticity of garlic, probably linked to its complicated genetics, which somehow compensate for lack of sexual reproduction.

Work done in 2009 by Gayle Volk and David Stern, Phenotypic Characteristics of Ten Garlic Cultivars Grown at Different North American Locations  addressed the observation that garlic varieties grown under diverse conditions have highly plastic environmental responses, particularly in skin color and yield. This is a very readable paper for non-academic readers. Ten garlic varieties were grown at twelve locations in the United States and Canada for two consecutive years to identify phenotypic traits of garlic that respond to environmental conditions. The purpose of the study was to determine which phenotypic traits are stable and which vary with location.

Inchelium Red softneck garlic – note the small cloves in the center.
Photo Southern Exposure Seed Exchange
  • Clove number, weight and arrangement, clove skin coloration, clove skin tightness and topset number, size and color stay true to variety independent of location.
  •  Mostly, varieties classified as hardneck types produced scapes and those classified as softnecks did not, but there were some exceptions.
  • Bulb size, bulb wrapper color and bulb elemental composition (flavor) are related to location, (the influence of the local environment, such as the weather in that production year and the soil mineral content), rather than variety. The intensity of the skin patterns is highly dependent on the location. Some general trends were noted, but no clear correlation was found. (Read the study for the details).
  • For good size, predictably colored and flavored garlic, buy seed garlic grown locally that yields well. When garlic is grown in similar conditions to those in which it was produced, yields can remain consistent or improve.

    Our softneck garlic in May.
    Photo Pam Dawling
  • Varieties that grow well thousands of miles away are not a guarantee of a good result in your garlic patch. They may not match the bulb size, shape, color and flavor listed in the catalogs.
  • When grown under the same environmental conditions, the leaf number before bolting, flowering date, the final stem length, the flower/topset ratio, and pollen viability vary from one variety to another.
  • Studies that compared bulb firmness, pH, soluble solids, moisture content and sugar content with appearance determined that many of these traits are independent of skin color across 14 garlic varieties.
  • Bulb size was highly dependent on growth location with northern sites producing larger bulbs overall than southern sites for at least half of the trial varieties. Regional differences between varieties with respect to bulb size were noted, but because the project had a limited number of sites, specific variety recommendations for different regions were not provided.
  • Bulb size and weight were positively correlated with soil potassium levels.
  • Bulb sulfur and manganese content (flavor) were correlated with soil sulfur and manganese levels.

    The famous Music garlic, a hardneck type – see the stem.
    Photo Southern Exposure Seed Exchange
  • The demand for high-quality fresh garlic is increasing as restaurants and consumers seek out local vegetables. Consumers are attracted to colorful, unique garlic varieties for different culinary uses. As variety name recognition in garlic increases, understanding which traits define particular varieties and which traits vary within cultivars, depending on environmental conditions, will be valuable for successful marketing of new garlic types.

Book Review: The Living Soil Handbook by Jesse Frost

Cover of The Living Soil Handbook by Jesse Frost

The Living Soil Handbook

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

  1. Inoculating composts are expensive, fine textured and biologically active. Vermicast (worm manure) is one example. Good for compost tea.
  2. Fertilizing composts such as composted poultry manure are fine textured nitrogen sources to use before planting.
  3. Nutritional composts supply organic matter, microbiology, nutrients, minerals, and ample amounts of carbonaceous material. They can be used in larger amounts.
  4. 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.

Jesse Frost

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 Fortier as “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.

Success with Planting Sweet Corn

Success with Planting Sweet Corn

Sweet corn at sunrise.
Photo by Wren Vile

Very fresh home grown organic sweet corn is so delicious! There’s no denying that sweet corn takes up a lot of space, so if you are really short of land, you may decide to forego corn. On the other hand, corn doesn’t take a lot of work, so if you have the space, but are short of help, corn is a good choice. This information comes from my book, Sustainable Market Farming.

This post about sweet corn include an overview of our corn-growing, dealing with weeds, and my slideshow on Succession Planting

This one Growing Sweet Corn for the Whole Summer – Organic Gardening … is one I wrote for Mother Earth News Organic Gardening .

Don’t Set Yourself up for Failure – Understand Sweet Corn Genotypes

 You can skip this section if you are only growing one variety of sweet corn, no other kind of corn, and it is at least 250’ (76 m) from anybody else’s corn. Otherwise, before you plant (hopefully before you buy seeds), read this.

With most crops, cross-pollination with other varieties or types is only a problem for those growing seed. With sweet corn, the seed is the food crop. Failure to isolate genotypes can lead to starchy unpleasant-flavored corn. Hybrids are made by crossing OPs. Making hybrids does not involve genetic engineering!

Our late corn beside sweet potatoes.
Photo Ezra Freeman

Nearly all genotypes of hybrid sweet corn include one of two recessive genes, su or sh2. Cross-pollination with other corn groups will produce the dominant genetics of field corn (that starchy stuff!)

  1. Normal Sugary (su or ns) types of sweet corn have old-fashioned corn flavor but are sweeter than OPs, although the sweetness disappears fairly rapidly after harvest. Most can germinate well in cool soil.
  2. Sugary-enhanced (se) and Sugary Enhanced Homozygous (se+ or se-se) types are more tender than (su), and slower to become starchy after harvest. Most, especially the (se+) types, are sweeter than (su) types.
  3. TripleSweet Sugary Enhanced (se-se-se) corn was created to be sweeter than se-se.
  4. Super Sweet (sh2) (also known as Shrunken) varieties are very sweet and slow to become starchy. If not isolated from all other types of corn, they will be very starchy and disappointing. They have very poor cold soil germination. The kernels are smaller than other corns, giving this type its name. The seed needs careful handling, to prevent mashing between a seeder plate and the hopper.
  5. Synergistic (se-se-se-sh2) types are combinations of genetics from the 3 previous genotypes. Each ear has 75% (se) kernels and 25% (sh2) kernels. They are flavorful, tender and sweet, but only when they are ripe. If picked too soon, they are a watery disappointment.
  6. Augmented Shrunken: these newer types contain the sh2 gene and some of the tenderness from the se types.

Isolate these three categories by at least 250’ (76 m) from each other:

  1. Super Sweet/Shrunken sweet corn varieties (sh2);
  2. all other types of sweet corn;
  3. all other types of corn (eg popcorn, dent corn, field corn)

Instead, you can isolate by time, sowing on dates to achieve at least a 12-14 day gap between maturity of the different plantings.

Your neighbor’s GMO sweet corn will cross with your corn, if it’s close enough for the wind to bring the pollen in. “Bt corn” has been genetically modified by incorporating Bt genes (Bacillus thuringiensis) so the corn includes its own insecticide. There are many reasons not to grow GMOs, including the spread of random bits of genetic material by cross-pollination with previously non-GMO crops, and the likely consequence of Bt-resistant insects, so I won’t give them more space here.

Sweet Corn Varieties

Our first sweet corn of the season. Bodacious
Photo Pam Dawling

Most Open Pollinated (OP) sweet corns are noticeably less sweet than modern sweet corn, so consider hybrids. OP varieties also deteriorate faster after harvest than hybrids, becoming starchier. Luther Hill is said to be the sweetest OP variety.

Some catalogs  indicate which varieties are suitable for certain latitudes. (Corn flowering is day-length sensitive.) Johnnys has a “Dynamic Comparison Chart” for the sweet corn varieties they sell. Many companies run cold-germination testing, and can tell you which varieties that year have good potential for early sowings. Others can rot in cold wet soil.

We plant corn six times through the season, often with three varieties in each sowing, as shown here in our late corn.
Photo Kathryn Simmons

For our location, we rely on the first three genotypes, supplemented with some of the others for variety.

  • Bodacious, 77 day (se) yellow, great flavor for one this early;
  • Kandy Korn, 89 day (se) delicious yellow workhorse;
  • Silver Queen, 96 day (su) white long-time favorite with some drought-tolerance and insect resistance;
  • Luscious, 77 day (se-se-se) bicolor (organically grown, good cold soil emergence);
  • Tuxedo, 80 day (se) yellow (tightly-wrapped, earworm resistant);
  • Sugar Pearl, 72 day (se+) white (very early, on short plants);
  • Argent, 86 day (se) white (tasty with tight earworm-defeating husks);
  • Spring Treat, 66 day (se+) yellow, one of the earliest yellow sweet corns with good cold soil tolerance.
Silver Queen white corn when mature (with bug).
Photo Kathryn Simmons

Sweet Corn Crop Requirements

A pH of 6.0-6.5 is ideal. Very fertile soil is needed, including high phosphorus. P deficiency shows up as purple leaf tips and margins; N deficiency as pale spindly stalks, yellow leaf tips and shriveled kernel tips; Mg deficiency as white-yellow striping between veins, with older leaves reddish-purple, perhaps with dead tips. Corn is sensitive to deficiencies of zinc or copper, but less so to low levels of boron. When looking for deficiencies, it helps to know what is normal for that variety, and to also consider water shortage.

If you used legumes in the winter cover crop preceding your later sowings of corn, a good stand can provide all the nitrogen the corn needs (100-125 lbs/acre; 112-142kg/ha). When the legume reaches its flowering point, the nitrogen nodules on the roots contain the maximum nitrogen.

The number of rows of kernels on the cob is set five weeks after emergence (although each variety has a number that is usual, under good conditions). Ear length and number of plants with double ears is established nine weeks after emergence. There’s the feedback on your farm’s fertility plan.

Sweet corn needs warm soil. Catalogs usually indicate the soil temperature (measured at 9am) recommended for each variety. 50°F (10°C) is the absolute minimum, and applies to treated seed and OP or (su) varieties only. 60°F (15.5°C) is better for most, and 65°F (18°C) or higher is required by some varieties. Common phenology signs for the season being advanced enough to sow corn are that white oak leaves are the size of squirrels’ ears and that ragweed is germinating. For us the first corn sowing date is usually around April 26, which is also our average last frost date.

Corn has no tolerance of frost, but escape from a late spring frost is possible if the seedlings are less than two weeks old and not yet very tall, as the growing point may still be underground. Thus, in a spring that promises to be warm and dry, it is possible to risk an early planting as much as 2-3 weeks before the last frost date. Having some transplant plugs for a back-up helps reduce the risk level.

Emergence takes 22 days at 50°F (10°C), 12 days at 59°F (15°C), 7 days at 68°F (20°C), and 4 days at 77°F (25°C).       

Our third planting of sweet corn on the left, fourth in the middle, 5th (barely emerging) on the right.
Photo Pam Dawling

Sowing Sweet Corn

2oz/50’ (55gm/15m) or 1lb/400’ (370gm/100m) are generally required. The (sh2) types have more seeds for the weight, because the shrunken seeds are lighter than other types – 200/oz (7/gm), 2500-5500/lb (5600-12300/kg); 1lb/1250’ (118gm/100m).

Corn is usually grown in rows 36” (0.9m) apart. We sow fresh seed 6” (15cm) apart, and if using seed from the year before, we sow at 4” (10cm) apart.  Depth of sowing can vary with the soil temperature, being a very shallow 0.5” (1cm) in spring, to 1” (2.5cm) in summer when soils are warmer lower down and seeds benefit from the extra moisture.

Seedlings are thinned to 8-12” (20-30cm) apart. 8” (20cm) spacing is usually optimal in terms of using available light and maximum yield for the area.. Upper leaves get 7-9 times the light of lower leaves, therefore it is important that the upper leaves are in good condition, to photosynthesize well. The lower ones get much less light, so may be broken off for easier harvesting.

Young sweet corn plants after imperfect hoeing.
Photo Pam Dawling

Corn is wind pollinated (though you will find plenty of bees collecting pollen, regardless). For best pollination, plant in patches at least 4 rows wide. Inadequate pollination leads to ears with flat undeveloped patches among the kernels.

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

Corn seed must have moisture to germinate. If you use a push seeder, irrigate after sowing. Because we sow small areas of many different varieties, and because people love to plant corn, we sow by hand. Our method has the advantage of delivering water right where the seed needs it. We measure and flag the rows, put out ropes on stakes along the rows, and make furrows (drills). The rope and its shadow make useful guides for keeping the rows straight. Next we have someone flood the drills with water from a hose, and we hand sow into the mud. After covering the seed and tamping the soil, we ignore the patch until the seed germinates. The watering in the furrow reliably provides enough moisture to get the plants up out of the ground. The ropes (about 12” (30 cm) above the ground) deter the crows, making it hard for them to land near the buried seeds. In recent years we have started using a seeder again, as the number of crows has worryingly declined.

We use overhead irrigation for corn. If you use drip tape, you might set out the tape, turn on the water for long enough to mark the soil with damp spots, then sow those spots with a jab planter.

Transplanting Sweet Corn

 It is quite possible to transplant sweet corn, so those in marginal climates don’t need to give up hope. We usually prepare some plugs the same day we sow our first corn outdoors and use these to fill gaps at the first cultivation. We use 200-cell Styrofoam Speedling flats (1”, 2.5 cm cells). We float these in a tank of water until we set them out. Some vegetable seedlings would drown if continuously in water, but corn does not. It is important to transplant the corn before the plant gets too big, and the taproot takes off. 2″-3” (5-7.5 cm) plants seem OK. The plugs transplant easily using butter knives.

I’ll write about Growing Great Sweet Corn in about a month.

 

Vegetable Garden Tips

 

Young Yukina Savoy plants.
Photo Ethan Hirsh

My virtual workshop on Asian Greens 

is available from Mother Earth News Fairs Online here.

The Food Independence Course Part Two  consists of eight video presentations, most of which come with pdf handouts. My contribution is Growing Asian Greens, and pairs nicely with the Guide to Asian Vegetables by Wendy Kiang-Spray, author of The Chinese Kitchen Garden: Growing Techniques and Family Recipes from a Classic Cuisine. Other topics include Dandelion Wine, Homemade Teas, Food Conversations, Passive Solar Greenhouse Design, Productive Growing from Home, and Growing Your Own Spices.

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Decoy Cabbage White Butterflies.
Photo Good Seed Co

Easy DIY Cabbage Butterfly Decoy!

The Good Seed Co blog posted this lovely idea for protecting brassicas from those white butterflies Pieris rapae. It’s based on the discovery that the butterfly is territorial. If it sees a slightly bigger competitor it flies away. I have not tested this system, but it sounds like an interesting and fun project that costs next to nothing.

http://goodseedco.net/blog/posts/cabbage-butterfly-decoy Posted 25th Jun, 2015 in On Our Mind by Robin Kelson

PageOfCabbageMoths_efile

Cut out paper decoy representations of the butterfly. Here’s a single page template you can download

We don’t have many cabbage butterflies  because we have both a predator – the paper wasp, and a parasite –  Cotesia glomerata, a parasitic wasp that lays its eggs in small (first instar) larvae of the Cabbage White Butterfly, or Imported Cabbage Worm (as we call it in the US). Cotesia larvae emerge from the caterpillars after 15-20 days and spin yellow or white cocoons on or near the host which dies when the wasps emerge. We often find clusters of these cocoons (about the size of cooked rice grains) on the underside of brassica leaves.

I learned from Bryan O’Hara in  No-Till Intensive Vegetable Culture that our friends, the Cotesia glomerata wasps that parasitize brassica caterpillars, and overwinter as pupal cocoons on the undersides of brassica leaves, will hatch out in spring on the very day the overwintered brassicas start to flower. The 20-50 day lifecycle needs brassica flowers, so don’t be in a hurry to cut down all your bolting greens! The flowers provide nectar for the adult wasps. The leaves, as we know, provide food for the caterpillars, which provide the host for the wasps to lay eggs in. The wasp larvae feed on the caterpillar until it dies, then pupate.

There’s an incredible National Geographic video of this cycle, showing parasitic wasp larvae swimming around inside a caterpillar, bursting out through its skin. The weirdest bit is that it is the dying caterpillar that spins the protective cocoons around the pupating larvae. And us who plant the brassicas that feed the caterpillars! Who is the farmer and who is farmed?

This video shows a paper wasp tackling a caterpillar.

This one shows Cotesia glomerata emerging

This one shows more about the parasitic Cotesia glomerata 


Savoy cabbage with frost. Savoys can take much colder temperatures than this!
Photo Lori Katz

Average First and Last Frost Dates

Harvest to Table has this helpful article:

Average First and Last Frost Dates for Cities, States, and Countries

Average frost dates – the last one in spring and the first one in the fall – are useful to know when planning your crops. Once you’ve calculated your planting out date for various crops, you can work back to set sowing dates for the crops you’ll transplant, and bed prep dates for every crop. You can also make a co-ordinated plan that paces the work and doesn’t have too much in any one week, or any while you plan to be on vacation. You can calculate your first sensible planting date for each crop, your last one and perhaps some in-between ones to keep up supplies throughout the season.

You can use your average first fall frost date to make sure you don’t plant frost-tender crops too late in the season when you have no hope of them maturing in time for a harvest. You can extrapolate beyond the frost date to figure out when to harvest the more hardy crops. See my Winter-Kill Temperatures chart for useful tips.

By looking at the number of frost-free days in your area you can see whether to grow long-season tender crops like watermelons, or whether it’s only worthwhile if you choose fast-maturing varieties.

The Harvest to Table website is a trove of clearly explained information.

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Soil thermometer with easy-to-spot backing in a bed of beets.
Photo Bridget Aleshire

Soil Temperatures

Average frosts are only averages. Actual frosts can sometimes happen two weeks either side of those dates. Frosts are only one particular temperature, and may not matter to the crop you’re planning for. Soil temperatures for germination and for planting are another important part of planning.

K-State Extension has a brief article on the importance of measuring your soil temperature.

The Empress of Dirt has a helpful list of Best Soil Temperatures for Sowing Vegetable Seeds, in alphabetical order by crop.

Harvest to Table also has a list, ranked by temperature, so you can see what you can plant this week.

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Scottish Climate Friendly Farming Video

Farmer Patrick Barbour, from Highland Perthshire, has won the search for Scotland’s climate friendly farming champion. Patrick’s innovative three-minute video entry, filmed at Mains of Fincastle, near Pitlochry stunningly illustrates the benefits of tree planting, species rich grassland, rotational grazing for cattle and sheep and stitching nitrogen fixing crops into pastures.  It is available to watch at: Next Generation Climate Change Competition

Patrick, Robert and Catherine Barbour of Mains of Fincastle, near Pitlochry
Photo The Scottish Farmer

Workhorse Crops for May

Young bush bean plants.
Photo Pam Dawling

Workhorse Crops for May

Workhorses crops are reliable under a wide range of conditions, including weather, soil, date and other variables. Some are easy to grow, some pump out lots of food, some are “insurance crops” like chard that stand in your garden until you need to harvest them, some are especially profitable (for those growing for market).

I’ve chosen 14 crops (including two pairs) to focus on in the next 12 months, ending April 2022: Asparagus, beans, cabbage, carrots, chard, garlic, kale and collards, potatoes, sweet corn, sweet potatoes, tomatoes, watermelons, winter squash, zucchini and summer squash.

My motivation for this series is to help all who want to be more efficient, productive and profitable (if selling) as other parts of our lives expand again.

Workhorse Crops to Plant in May

May is a busy planting month here in central Virginia and probably most places in the northern hemisphere. Ten of our 14 Workhorse Crops can be planted once frosts are behind us.

Beans: We grow bush beans because we don’t like putting up trellises. In the past we had uncontrolled Mexican Bean Beetles that destroyed slower-to-mature pole beans. We found we could get crops of bush beans faster and sow them every few weeks or so to get a good supply of presentable beans every couple of days. Click this link to read about soaking bean seed, using inoculant, sowing through biodegradable plastic mulch using a jig, sowing sunflowers in our bean rows as place-markers when harvesting. See my phenology post for information on when it’s warm enough to start sowing beans (and other crops) where you are.

Carrots: I wrote a lot about carrots in the past year, when the monthly series was on root crops. See this post on preparing beds for sowing carrots, and weeding and thinning. Check out this post on flame-weeding, if you plan lots of carrot-growing!

Multicolored chard. Wren Vile

Chard: A great insurance crop – it provides leafy greens when you need them, and you can ignore it when you have plenty of other vegetables! As a biennial, chard will not bolt the first year (unless stressed by lack of water). We use chard for fresh greens in summer, when kale, collards, broccoli and cabbage from the spring have long gone. Because we don’t need chard until late May, we don’t sow until late March. We transplant in late April, into a hay mulch. This crop will be in the ground until mid-winter, and mulch will keep back most of the weeds. You could, of course, sow chard earlier if you want to eat it earlier. We also grow chard through the winter in our hoophouse, where it feeds us during the Hungry Gap.

Potatoes: I wrote a special series on potatoes last year. Click the link to access the whole series, starting with planting in April. Here we plant in March and June. You can plant at any date in between, so long as you have 80 days until your first frost. If time is a bit short, choose a fast-maturing variety (or be satisfied with small potatoes that won’t store).

Sweet corn: we make 6 sowings of sweet corn, to harvest from July 4 to mid-October. Start planting sweet corn when the leaves of the white oak are as big as squirrel’s ears. Click the link to check our planting dates, and to read about our first sowing of the year, catching raccoons and skunks, avoiding mixing types of corn and to view my slide show on succession planting. There’s a confusing aspect of hybrid corn varieties: if you plant a mixture of different genotypes, it can lead to starchy unpleasant-flavored corn. Also don’t plant Indian corn, popcorn or any kind of flint or dent corn within 600′ (180 m) of your sweet corn. For this reason we grow only sweet corn in our garden.

Our first sweet corn of the season.
Photo Pam Dawling

Sweet potatoes: I wrote about planting sweet potatoes in 2020. Modern varieties of sweet potatoes grow to a good size in as little as 90 days, so they are not just for the South! The further north you are, the longer the daylight at midsummer and the more photosynthesizing the plants can do. I have known people grow sweet potatoes in hoophouses if their climate isn’t warm enough outdoors. This can fit with winter use of the hoophouse for greens and roots. My book Sustainable Market Farming contains a whole chapter on this crop, including growing your own slips, but it’s too late to start that this year. Wait for the soil to warm before planting out your sweet potato slips. We plant ours a couple of weeks after the last frost, around the time we transplant peppers and okra.

Tomatoes: We plant out our main crop at the very beginning of May, unless the weather is too cold. To my surprise, I find I haven’t written much about transplanting tomatoes outdoors. Here’s a post about planting tomatoes in our hoophouse. We use the same techniques in the hoophouse and outdoors. We transplant one row of tomatoes down the centerline of a 4ft (1.2 m) bed, 2ft (60 cm) apart. Outdoors, once the weather has settled so that we’re confident we won’t need rowcover any more, we stake and stringweave. We install a steel T-post every two plants (4ft /1.2 m) apart and start stringweaving when the plants are about 12ins (30 cm) tall. I’ll say more about stringweaving later in the year.

Watermelon transplants in a Winstrip plug flat. Watermelons give earlier harvests from transplants, and plants in plug flats transplant easier then from open flats.
Photo Pam Dawling

Watermelons: Watermelon growing isn’t easy, but the rewards are so wonderful, that I gave watermelon a “Circus Pony” place among the workhorses! We transplant our watermelons, to get ripe ones as early as possible. Melons are tricky to transplant, as the roots don’t do well if disturbed. We have successfully used soil blocks, and these days we use Winstrip 50-cell trays. Watermelons grow very well on black plastic mulch, which warms the soil as well as keeping weeds at bay. The first year we switched from using hay mulch to biodegradable plastic mulch, we were astounded to get ripe melons a full month earlier!

It’s important to keep the little seedlings in the greenhouse warm and in very good light, and away from drafts. Be careful not to overwater. They can keel over very quickly and once the stem collapses, remove that seedling before others die too. The goal is short stems!

When you transplant, get the start out of the flat and into the ground as quickly as possible with as little root damage as you can manage. This is not a crop where one person plops the plants out down the bed and someone follows planting them! Make the hole in the soil (through the plastic if you’re using that), by wiggling the trowel from side to side. Don’t dig a hole as if you are in a sand box, with a spoil heap at the side. Just form a space the right depth to get the whole of the stem in the ground.

Next gently pop the transplant out of the flat, perhaps using a table knife down the side of the cell. Push up from underneath. If all goes well, you’ll have the plant in a little block of soil (yes, like a soil block). Slide the transplant into the hole. You want all the leaves above ground, all the roots and stem in the ground. If the hole is too deep, lift the transplant carefully and scrape some soil into the hole. You don’t want to end up with the plant in a dip, as this can rot the stem. If the hole is not deep enough, you can to some extent hill up soil around the stem to protect it. You don’t want any of that fragile stem visible!

Water the day before, and one hour before transplanting, to help the soil hold together, and so that the plant has some reserves of water to see it through the initial shock of being set out. As you are transplanting, pause and water newly set plants every 20 minutes or so. Afterwards, water the whole planting and repeat on the 2nd, 3rd, 5th, 7th days and once a week after that.

Winter squash: By contrast, winter squash are very easy, and they store for months at room temperature. A true workhorse. We direct sow at the end of May, with the goal of harvesting in September and October, the last ones making Halloween lanterns. Soil should be at least 60°F (15.5°C), and all danger of frost should be past.

Young squash plant.
Pam Dawling

We have grown about 400ft (120 m) for 100 people, and mostly focus on Butternuts, Moschata types that grow best where we are and store longest. This is the type to focus on if you want trouble-free squash, with no damage from borers or cucumber beetles. The tougher stems are better able to repel invaders. They need warm growing temperatures above 60°F (16°C). As well as Waltham Butternuts, we include the large Cheese pumpkin, the long-storing Seminole, and the gigantic Tahitian Butternut. We also grow a couple of Maxima squashes which store quite well:  Cha-cha kabocha, and the large blue Jarrahdale, which have relatively high resistance to squash bugs compared to others in this group. Red Kuri, Festival (sweet dumpling type) and the New England Pie pumpkin are Pepo squashes, suitable for storing a few weeks only. (Pumpkins are squashes.) We grow some of these because they are sooner to harvest. Really they are more of a fall squash than a winter squash.

Winter squash do need a lot of space for each plant. This can mean a lot of hoeing until the vines spread, or mulch. Some can take 90-120 days to reach maturity, so plan carefully to be sure of getting a harvest. For dryland farming, without irrigation, it is important not to move the vines to new positions: the dew and rain drips from the leaf edges encourage root growth directly below the vines (where they get the most water and shade).

Sow 0.5”-1” (1-2 cm) deep. Either “station sow” 2 or 3 seeds at the desired final spacing, or make a drill and sow seeds 6” (15 cm) apart. There are various stick planters and jab planters that can be used for this kind of station sowing. Thin later. Rows will need to be 6’ (1.8 m) apart, or more. 9’ (2.7 m) between rows for the vining ones. Some growers plant in a square pattern so that spaces between rows can be mechanically cultivated in both directions. Bush varieties take less space than the vining types, and rows can be 4’ (1.2 m) apart.

You can transplant winter squash if you need to. We did this one year after our fields flooded. We started seeds in cell packs a week before our usual sowing date of 5/25. It worked just fine.

Summer squash plants under insect netting.
Pam Dawling

Zucchini (courgettes) and summer squash: Zucchini is a subset of summer squash. These are easy to grow, fast to produce warm weather crops. We make a succession of five or six plantings each year, so that we can harvest every day. Each sowing is half a yellow squash (Zephyr, Gentry) and half a zucchini (TenderGrey, Noche, Golden Glory). We grow our earliest squash in the hoophouse, setting out transplants at the beginning of April. Our first outdoor crop is also from transplants. After that, the soil is warm enough to direct sow – 60°F (15.5°C).

After transplanting or sowing, we hoop and cover the row with insect netting (rowcover also works if it has no big holes). We have many bugs that like these plants, especially the striped cucumber beetles, so we keep the rows covered until female flowers appear. At that point we need the service of the pollinators, unless the squash is parthenocarpic (sets fruit without pollination). At that point we pack away the covers, hoe and thin the squash to 24” (60 cm). it would be better to thin sooner, but we rarely find the time.

Zucchini and summer squash are another crop type that we succession sow, to get a continuous supply. More about succession planting another time. The time from sowing to harvest is only around 50 days.

Workhorse Crops to Harvest in May

Asparagus photo by Kathryn Simmons

Asparagus can be harvested if you have a patch. If not start to prepare a patch to plant out one-year crowns next early spring. Remove all perennial weeds while growing a series of cover crops. If you have asparagus, you probably know to snap off at ground level all the spears above a certain length. We chose 7” (18 cm). Do this every day for the 8-week harvest period. Daily harvest will also remove asparagus beetle eggs, controlling the pest level.

A bed of Early Jersey Wakefield cabbage in mid-May.
Photo Pam Dawling

Cabbage can be ready from late May, if you made an early sowing of fast-maturing varieties. Farao or Early Jersey Wakefield can take only 60 days.

Carrots can be ready from late May, if you sowed some in mid-late February

Chard is ready for harvest from late May (earlier if sown earlier), see above.

Harvesting garlic scapes in May
Photo by Wren Vile

Garlic scapes appear in hardneck garlic plants. Here it is also an indicator that our garlic will be ready to harvest in three weeks.

Kale and collards can be harvested until they are bolting, as long as the flavor is acceptable. Read more about bolting here.

Zucchini and summer squash from mid-May,

From storage: carrots, potatoes, sweet potatoes, winter squash

Workhorse Crops Special Topic: Deciding Which Vegetable Crops to Grow

Here’s a slideshow to help you decide which crops to grow. Some of the points are for commercial growers, some apply to anyone growing vegetable crops.

Deciding Which Vegetable Crops to Grow, Pam Dawling

Cuban Agriculture, Dinner at the Garden of Miracles restaurant with Rafael Betancourt

Staghorn fern at the Garden of Miracles restaurant, (Jardin de los Milagros Paladar) Havana, Cuba. Photo Pam Dawling
This was day 7  of my Agroecology Tour of Cuba with the Organic Growers School (Monday January 13, 2020) 

Dinner at the Garden of Miracles (Jardin de los Milagros Paladar) farm-to-table restaurant, with guest speaker, Rafael Betancourt

Overview of the Cuban Economy, Cooperatives and Politics

We rearranged the tables in a square, to better hear the speaker, Rafael Betancourt, talking about the Cuban economy, cooperatives and politics. First I’ll write about the talk, then about the restaurant.

The Cuban economy has changed from the export of plantation products (using enslaved people) to tertiary tourism, remittances from ex-pats in the US and training (medical and other). Sand and Sun tourism is waning, Agritourism could be increased. Farmers can earn more money by catering for tourists than from selling crops. “Cuba doesn’t export any food except apples.”

Rafael Betancourt believes it is geographically inevitable that the US and Cuba will come together. Right now we’re at a juncture. Obama’s executive orders were been rolled back by Trump. Cubans prefer the word “blockade” to “embargo” (which implies bilateral actions.) The Helms-Burton Act of 1996 included that US dollars cannot be banked in Cuba. It’s costly for them to keep moving suitcases of US dollars around.

The US and Cuban economies are entangled but limited. Food imports from the US are allowed but have to be paid in cash as soon as the product arrives. [This is different from what we were told about US chicken not leaving the US until it had been paid for in Euros and cleared the European Bank.]. Exports to the US are almost always prevented, except that tourists export rum, cigars, honey, etc.

Rice in the Time of Sugar. Book cover. Louis A Pérez

Rice in the Time of Sugar: The Political Economy of Food in Cuba, a book by Louis A Pérez, asks “How did Cuba’s long-established sugar trade result in the development of an agriculture that benefited consumers abroad at the dire expense of Cubans at home?”

“In this history of Cuba, Louis A. Pérez proposes a new Cuban counterpoint: rice, a staple central to the island’s cuisine, and sugar, which dominated an export economy 150 years in the making. In the dynamic between the two, dependency on food imports—a signal feature of the Cuban economy—was set in place.”

U.S. rice producers resisted Cuban efforts to expand rice production, because they relied on the Cuban market for rice. Cuban sugar growers relied on the U.S. market. U.S. growers prepared to cut the sugar quota to control Cuban rice markets. In the 1950s, when revolutionary tensions in Cuba were strengthening, U.S. rice producers and their allies in Congress clashed with Cuban producers supported by the Batista government. U.S. interests won out, contributing to undermining Batista’s ability to govern. Cuba’s inability to be self-sufficient in rice production continues to this day, but U.S. rice growers have lost the Cuban market. In the face of the U.S. embargo, Cuba buys low quality rice from Vietnam, that does not sell well in Vietnam. They are learning Vietnamese water-conserving rice-growing methods.

Pigs make good use of kitchen scraps. This one lived at Vinales Forest Farm. Photo Pam Dawling
  • Cuba does not need to import eggs, but they do import chicken feed.
  • Food waste from restaurants may be taken home by the workers, or sent to schools and hospitals, or become pig food. There is no State strategy.
  • Portion size: there is a scarcity mentality in Cuba, leading to a frugal use of resources.
  • Cubans going overseas bring back empty Tropicana juice jugs in their luggage.
  • Recycling varies from place to place. The State purchases cans, metal, plastic and paper. They sell the products back to the manufacturing company.

Climate change and resiliency: In the US, food waste accounts for more than 20% of greenhouse gases. Cuba has a strategy for reducing greenhouse gases. Cuba didn’t make many of the greenhouse gases, but will be strongly impacted by climate change. The coastal resorts are vulnerable to sea level rise, and suffer badly from hurricanes. They have a big Reforestation Project, adding more trees every year. Cuba is committed to 20% renewable energy sources by 2020. Cuba became the first country in the world to completely phase out incandescent light bulbs.

The top five Cuban products Rafael Betancourt would like to see exported to the US: Cancer vaccine, other pharmaceuticals, high technology software, beer, services. Currently the label “Remittance” covers business transactions.

Academic Exchanges: A US institution would need to partner with a Cuban academic institution. Cuba could help with rice post-harvest equipment and know-how; Milk production (they have a very cheap method of producing 1 liter/day); Cattle feed; Biofuels using sugar bagasse; They could use help with setting up a certifying board and certifying and exporting organic food; They would like to provide their own organic seeds (many Cuban vegetable seeds are imported, but row crop seeds are grown there).

 

Cuban money.
Photo Thea LaMastra

The story of the CUC: The US embargo was designed to push Cuba towards the USSR. Most imports came from the USSR. When the Soviet Union collapsed, Cuba experienced an 80% reduction in imports and exports. Remittances from Cubans overseas helped island survival. Tourism grew, and hard currency started coming in, but the banks didn’t touch it. Cubans became allowed to possess hard currency, and a chain of stores opened, selling goods in US$.

The CUC was invented in 1994 after the collapse of the Soviet Union, to substitute for US$, which people were then not allowed to spend. People converted their dollars into CUCs. Domestic tourism increased, and the CUC stimulated imports and suppressed exports. The exchange rate was about 24 Cuban pesos to 1 CUC. The State promises to honor the value of the peso. The CUC was phased out on January 1, 2021, after that plan being a kind of a secret.  The duty-free shop at Havana airport sells goods for US$ or pesos, but not CUCs. We were warned not to take CUCs out of the country, hoping to use them in the future. (US banks and currency exchange bureau don’t deal with Cuban money at all.) The Peso is now officially set at 24 Cuban pesos to 1 US dollar

Garden of Miracles (Jardin de los Milagros Paladar) farm-to-table restaurant

The Garden of Miracles roof top garden, Havana, Cuba Photo Alan Ismach
Garden of Miracles Restaurant roof garden vegetable beds, Havana, Cuba.
Photo Pam Dawling

We visited the restaurant roof garden, which supplies the restaurant. There were table-top beds of greens, and beehives. We saw it in the dark, so my photos and impressions are murky! I believe they must buy a lot of their ingredients from elsewhere.

Repurposed containers for growing vegetables. Garden of Miracles restaurant, Havana, Cuba. Photo Pam Dawling
Vegetables growing in the Garden of Miracles roof top garden
Photo Alan Ismach
Garden of Miracles rooftop vegetable garden, Havana, Cuba.
Photo Pam Dawling
Rooftop beehives at the Garden of Miracles farm-to-table restaurant, Havana, Cuba.
Photo Pam Dawling
Meal at the Garden of Miracles Restaurant, Havana, Cuba.
Photo Thea LaMastra

 

Vegetable Seed Germination Temperatures and Phenology

Summer Lettuce Nursery Seedbed with Concept, De Morges Braun, New Red Fire and Loma lettuces.
Photo Bridget Aleshire. Lettuces are impossible to germinate if the soil is too hot. We use shadecloth (folded over on the right), a soil thermometer and ice cubes.

Vegetable Seed Germination Temperatures

Here is a table of vegetable seed germination temperatures. These apply to soil temperatures when you sow directly in the ground, and to air temperatures when you sow indoors in small containers. If your indoor air temperature is not warm enough when you want to sow your chosen crop (watermelons, anyone?) you can make a small warm place, or use a professional heat mat, or, for a small scale, germinate seeds in an instant pot! If you have one of these handy cooking devices, check the lowest setting. Perhaps labeled for making yogurt, it might be 91°F (33°C). Look at my chart below and see if your seeds will germinate at that temperature. You’ll have to experiment for the seeds which germinate well at 86°F (30°C) but not at 95°F (35°C). Don’t try this with spinach or lettuce! You might be surprised to see that some cool weather crops, like broccoli and cabbage, can germinate just fine at high temperatures!

You can see my chart is a work in progress, so if you can add any info, please leave a comment on this post. Bold type indicates the best temperature for that vegetable seed. The numbers indicate how many days it takes that seed to germinate at the temperature at the head of the column. Where I don’t know the number of days, I have put “Yes” if it does germinate at that temperature, “no” if I think it doesn’t and a question mark where I plain don’t know. I would love to know, so if you can resolve the uncertainties, please speak up! I’ve also used the words “best’, “min” and “max” which I hope are self-evident.

Vegetable seed germination

 

Ice cubes over newly sown lettuce seed, to help germination in hot weather. Shadecloth is folded open on the left. Photo Bell Oaks

Soil Thermometers

Soil thermometer.
Photo by Green Living/Taylor

To measure the temperature of the soil outdoors, I recommend a dial-type soil thermometer. Ignore the vague guidelines on Min/Optimal/Max and use the table above. The usual practice is to check the temperature at 9am each day, and if you are unsure, check again the next day. In some cases it is best to get 4 consecutive days of suitable temperatures, or even (in spring!) a few days of rising temperatures.

Harbinger weeds of spring and fall

Flowering Purple (or Red) Dead Nettle, with honeybee.
Credit Kathryn Simmons

The progress of emergence of different weeds in the spring shows us how quickly the soil is warming up. I wrote about that here. In that post you can see photos of flowering chickweed, purple dead nettle, and henbit.

Chickweed seedling.
Photo from UC IPM Weed Gallery

In the fall we will be waiting for the soil to cool enough to sow spinach. I have a blog post about this here, and also photos of those three weeds as seedlings, which is what we are looking for in the fall, as an indication that the soil has cooled down enough for them (and spinach!) to germinate.

Phenology

I have a post about phenology here.You can read some of the details of when to plant by natural signs. For instance, we sow sweet corn when white oak leaves are the size of a squirrel’s ear. I got excited this past weekend (April 10) when I saw wind-driven twigs on the ground with oak leaves definitely bigger than squirrels’ ears. But they were Red Oak, not White Oak.

The chart in that 2013 post has now got corrupted (at least it has on my screen), so here is a pdf

Phenology Record

 

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

Phenology records are a useful guide to when to plant certain crops, and a way to track how fast the season is progressing right where you are. Phenology involves recording when certain wild and cultivated flowers bloom, seedlings emerge, or various insects are first seen. These natural events can substitute for Growing Degree Day calculations. Certain natural phenomena are related to the accumulated warmth of the season (rather than, say, the day-length), and by paying attention to nature’s timetable you will be in accord with actual conditions, which vary from year to year, and are changing over a longer time-scale.

Keeping your own phenology record will help build resilience in the face of climate change. Ours might be interesting to you, but unless you live in central Virginia, you can’t use our dates. You do need to make your own. This can be a great home-schooling project, or a crew I-Spy competition, or a calming end-of-day walk around your gardens.

Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

Our pond iced over.
Photo Ezra Freeman

Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

I keep records of how well our crops do in the colder season, both outdoors and in our double-layer hoophouse. I note each increasingly cold minimum temperature and when the various crops die of cold, to fine-tune our planning for next year. We are in zone 7a, with an average annual minimum temperature of 0-5°F (-18°C to -15°C).

The winter 2020-2021 was mild, with our lowest temperature being a single late January night at 10°F (-12°C). We had one night at 11°F (-12°C) one at 17°F (-8°C), three at 18°F (-8°C also) and one at 19°F (-7°C). very little snow or ice. Similar to temperatures in the 2019-2020 winter.

The winter of 2018-2019 had lowest temperatures of 6°F (-14°C) in late January 2019, 8°F (-13°C) in December 2018 and a couple of 11°F (-12°C). In early January 2018, we had some extremely cold temperatures of -8°F and -9°F (-22°C and -23°C). Averaging our winter low over those four winters 2017-2021 gives 4.8°F (-15°C), within the zone 7a range.

Georgia Cabbage Collards, good down to 20F (-7C) Photo Southern Exposure Seed Exchange

New Info this winter

I’ve added in some temperatures for collard varieties (Georgia Cabbage collards, McCormack’s Green Glaze, variegated collards) from the Heirloom Collards Project, and also gained some info on spinach (Long Standing Bloomsdale), kales (Rainbow Mix Lacinato) and mustards (Chinese Thick-Stem) from Southern Exposure Seed Exchange. I’ve added in their suggestions on cold-tolerant early spring lettuces, Crawford, Simpson Elite, Susan’s Red Bibb and Swordleaf.

My results from other years still hold up.

Swordleaf lettuce on the right with another lettuce and radishes in spring.
Photo Bridget Aleshire

Using the List

Unless otherwise stated, these are killing temperatures of crops outdoors without any rowcover. All greens do a lot better with protection against cold drying winds. Note that repeated cold temperatures can kill crops that can survive a single dip to a low temperature, and that cold winds, or cold wet weather can destroy plants quicker than simple cold. Crops get more damage when the weather switches suddenly from warm to cold. If the temperature drops 5 or more Fahrenheit degrees (about 3 C degrees) from recent temperatures, there can be cold damage. The weatherman in Raleigh, NC says it needs 3 hours at the critical temperature to do damage. Your own experience with your soils, microclimates and rain levels may lead you to use different temperatures in your crop planning.

Reflect spinach in the open got damaged but not killed at -9F.
Photo Pam Dawling

Outdoor killing temperatures of crops (unprotected unless stated)

35°F (2°C):  Basil.

32°F (0°C):  Bush beans, some cauliflower curds, corn, cowpeas, cucumbers, eggplant, limas, melons, okra, some pak choy, peanuts, peppers, potato vines, squash vines, sweet potato vines, tomatoes.

27°F (-3°C): Many cabbage varieties, Sugarloaf chicory (takes only light frosts).

25°F (-4°C): Some cabbage, chervil, Belgian Witloof chicory roots for chicons, and hearts, Chinese Napa cabbage (Blues), dill (Fernleaf), some fava beans (Windsor), annual fennel, some mustards (Red Giant, Southern Curled) and Asian greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), onion scallions (some are much more hardy), radicchio, rhubarb stems and leaves.

22°F (-6°C): Some arugula (some varieties are hardier), Bright Lights chard, endive (Escarole may be a little more frost-hardy than Frisée), large leaves of lettuce (protected hearts and small plants will survive colder temperatures).

20°F (-7°C): Some beets (Bulls Blood, Chioggia,), 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, celeriac, celtuce (stem lettuce), some collards (Georgia Cabbage Collards, variegated collards), some head lettuce, some mustards/Asian greens (Tendergreen, Tyfon Holland greens), flat leaf parsley, radicchio (both Treviso and Chioggia), radishes (Cherry Belle), most turnips (Noir d’Hiver is the most cold-tolerant variety).

Large oat plants will get serious cold damage. Oats seedlings die at 17°F (-8°C)

Canadian (spring) field peas are hardy to 10-20°F (-12 to -7°C).

Ruby chard, good down to 15°F (-9.5°C). hardier than Bright Lights, but less hardy than green chard varieties.
Photo Kathryn Simmons

15°F (-9.5°C): Some beets (Albina Verduna, Lutz Winterkeeper), beet leaves, some broccoli and cauliflower leaves, some cabbage (Kaitlin, Tribute), covered celery (Ventura), red chard, cilantro, fava beans (Aquadulce Claudia), Red Russian and White Russian kales, kohlrabi, some lettuce, especially medium-sized plants with 4-10 leaves (Marvel of Four Seasons, Olga, Rouge d’hiver, Tango, Winter Density), curly leaf parsley, rutabagas (American Purple Top Yellow, Laurentian), broad leaf sorrel, most covered turnips, winter cress.

12°F (-11°C): Some beets (Cylindra,), some broccoli perhaps, some Brussels sprouts, some cabbage (January King, Savoy types), carrots (Danvers, Oxheart), most collards, some fava beans (mostly cover crop varieties), garlic tops if fairly large, Koji greens, most fall or summer varieties of leeks (Lincoln, King Richard), large tops of potato onions, covered rutabagas, some turnips (Purple Top).

10°F (-12°C): Covered beets, Purple Sprouting broccoli for spring harvest, a few cabbages (Deadon), chard (green chard is hardier than multi-colored types), some collards (Morris Heading can survive at least one night at 10°F), Belle Isle upland cress, some endive (Perfect, President), young Bronze fennel, Blue Ridge kale, probably Komatsuna, some leeks (American Flag (Broad London), Jaune du Poiteau), some covered lettuce (Pirat, Red Salad Bowl, Salad Bowl, Sylvesta, Winter Marvel), Chinese Thick-Stem Mustard may survive down to 6°F (-14°C), covered winter radish (Daikon, China Rose, Shunkyo Semi-Long survive 10°F/-12°C), Senposai leaves (the core of the plant may survive 8°F/-13°C), large leaves of savoyed spinach (more hardy than smooth-leafed varieties), Tatsoi, Yukina Savoy.

Oats cover crop of a medium size die around 10°F (-12°C). Large oat plants will die completely at 6°F (-17°C) or even milder than that.

Garlic shoots poking through the mulch in January. Survive down to 5°F (-15°C), and if killed, will regrow from underground.
Photo Pam Dawling

5°F (-15°C): Garlic tops even if small, some kale (Winterbor, Westland Winter), some leeks (Bulgarian Giant, Laura), some bulb onions, potato onions and other multiplier onions, smaller leaves of savoy spinach and broad leaf sorrel. Many of the Even’ Star Ice Bred greens varieties and the Ice-Bred White Egg turnip are hardy down to 6°F (-14°C), a few unprotected lettuces if small (Winter Marvel, Tango, North Pole, Green Forest).

0°F (-18°C): Chives, some collards (Blue Max, Winner, McCormack’s Green Glaze), corn salad (mâche), garlic, horseradish, Jerusalem artichokes, Even’ Star Ice-Bred Smooth Leaf kale, a few leeks (Alaska, Durabel, Tadorna); some bulb onions, yellow potato onions, some onion scallions, (Evergreen Winter Hardy White, White Lisbon), parsnips (probably even colder), salad burnet, salsify (?), some spinach (Bloomsdale Savoy, Long Standing Bloomsdale,  Olympia). Walla Walla onions sown in late summer are said to be hardy down to -10°F (-23°C), but I don’t trust below 0°F (-18°C)

Crimson clover is hardy down to 0°F (-18°C) or perhaps as cold as -10°F (-23°C)

-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.

A cover crop mix of winter rye, hairy vetch and crimson clover.
Credit Kathryn Simmons

-10°F (-23°C) Austrian Winter Field Peas and Crimson clover (used as cover crops).

-15°F (-26°C) Hairy vetch cover crop – some say down to -30°F (-34°C)

-20°F (-29°C) Dutch White clover cover crops – or even -30°F (-34°C)

-30°F to -40°F (-34°C to -40°C): Narrow leaf sorrel, Claytonia and some cabbage are said to be hardy in zone 3. I have no personal experience of this.

-40°F (-40°C) Winter wheat and winter rye (cover crops).

Hoophouse Notes

Winter crops snug in our hoophouse in a December snowstorm.
Photo Pam Dawling

Our double-plastic hoophouse keeps night time temperatures about 8F (4.5C) degrees warmer than outdoors, sometimes 10F (5.5C) degrees warmer. Plus, plants tolerate lower temperatures inside a hoophouse. The soil stays warmer; the plants recover in the warmer daytime conditions (it seems to be the night+day average temperature that counts);

In the hoophouse (8F (4.5C) degrees warmer than outside) plants without extra rowcover can survive 14F (7.7C) degrees colder than they could survive outside; with thick rowcover (1.25oz Typar/Xavan) at least 21F (11.6C) degrees colder than outside.

For example, salad greens in our hoophouse can survive nights with outdoor lows of 14°F          (-10°C). Russian kales, lettuce, mizuna, senposai, spinach, tatsoi, turnips, Yukina Savoy survived a hoophouse temperature of 10.4°F (-12°C) without rowcover, -2.2°F (-19°C) with. Bright Lights chard got frozen leaf stems.

Lettuce Notes

Lettuce varieties for a solar-heated winter greenhouse or hoophouse in zone 7a: (hardiest are in bold) Buckley, Ezrilla, Green Forest, Green Star, Hampton, Hyper Red Rumpled Wave, Marvel of Four Seasons, Merlot, New Red Fire, North Pole, Oscarde, Outredgeous, Pirat, Red Cross, Red Sails, Red Salad Bowl, Red Tinged Winter, Revolution, Rouge d’Hiver, Salad Bowl, Sylvesta, Tango, Winter Marvel, Winter Wonderland.

Cold-tolerant early spring lettuces include Buckley, Crawford, Green Forest, Hampton, Merlot, New Red Fire, Revolution, Simpson Elite, Susan’s Red Bibb and Swordleaf.

Notes on Chicories and Endives

Verona Red radicchio, hardy to about 20°F (-7°C).
Photo Southern Exposure Seed Exchange

Chicories and endives fall into two groups, but they are confusing because the common names sometimes suggest the opposite group than they are botanically. Here’s the best info I have.

Cichorium intybus, commonly called chicories, are mostly heading crops. The group includes radicchio, both Treviso and Chioggia – hardy to about 20°F (-7°C). Belgian Witloof endive (the kind for forcing chicons) is also a chicory. It dies at 25°F (-4°C). Sugarloaf chicory is the least hardy chicory, and dies at 27°F (-3°C).

Cichorium endivia, commonly called endives, are mostly loose-leaf crops, less cold-hardy than intybus types (chicories). This group includes Frisée types and escaroles, which are also known as Batavian endives. They generally survive down to 22°F (-6°C), although Perfect and President endives can survive down to 10°F (-12°C) – can anyone confirm or deny this?

© Pam Dawling 2021


Go to my Events Page for more information on these online events

Mother Earth News Fair Online: Food Independence Course Part Two was released on 3/26/21.

It consists of eight video presentations, most of which come with pdf handouts. My contribution is Growing Asian Greens, and pairs nicely with Guide to Asian Vegetables with Wendy Kiang-Spray, author of The Chinese Kitchen Garden: Growing Techniques and Family Recipes from a Classic Cuisine. Other topics include Dandelion Wine, Homemade Teas, Food Conversations, Passive Solar Greenhouse Design, Productive Growing from Home, and Growing Your Own Spices.

You can subscribe to the All-Access Bundle for $2.99/month (or $35 for a year).

My previous contribution is an 8-part Garden Planning Course

I also did a workshop on Winter Cover Crops for Gardeners as part of the Winter Gardening Course.

All these and many more videos and handouts are available as part of the All-Access Bundle.

 

Root Crops in April – the Hungry Gap

Young Cylindra beets in early May.
Photo Pam Dawling

Root Crops to Plant in Central Virginia in April

We are in cold-hardiness zone 7a, with an average last frost of 4/29. Those in other climate zones can study our Root Crops in May or Root Crops in March for information more useful in their area.

Outdoors we can sow  carrots #4 & #5, parsnips, radishes #2, (last date 4/15, sow on the shoulders of a newly transplanted lettuce bed to save space), beets (last date 4/15, hand sown or with an EarthWay seeder Chard plate, 2 or 3 passes. 1 cup sows 360 ft/110m)

Here we can plant potatoes anytime in April.

It is too late for us to sow any root crops in the hoophouse. (Besides, we want tomatoes!)

Having good stored crops like these beets will feed you through the Hungry Gap.
Photo Pam Dawling

Root Crops to Harvest in Central Virginia in April

As in January, February and March in central Virginia, in most of April there are still no roots to harvest outdoors except overwintered parsnips and maybe carrots, Jerusalem artichokes and horseradish.  Radishes from the first outdoor sowing will be ready at the end of April. We can usually harvest radishes until the end of May. Our hoophouse radishes usually finish in early April. By then it is hot and any remaining radishes bolt.

From storage, if we still have them, we can eat beets, carrots, celeriac, kohlrabi, parsnips, potatoes, rutabagas, sweet potatoes, and turnips.

This is the Hungry Gap (see Special Topic for April below)

Colorado Potato beetle late stage larva
Photo Pam Dawling

Other Root Crop Tasks in Central Virginia in April

  • If you are growing your own sweet potato slips, cut 6-12” (15-30cm) slips daily and stand them in water. Once a week, plant rooted slips in 4” (10cm) flats.
  • Hill up potatoes when 6” (15cm) high. Cover half the vine. Repeat after 2 weeks. This deals well with weeds and gives the potatoes more soil to grow into.
  • Potato beetles: Use Spinosad [or Neem] once larvae are seen, if there are more than 50 adults/50 plants or more than 200 larvae/100 plants. If you have fewer, you can leave them alone. Spinosad: Spray when bees are not flying (early morning or late evening.) Shake well, 1-4 Tbsp/gall (1fl.oz=2Tbsp=30ml.) Approx 8-30 ml per liter. Repeat in 6 days. Clean and triple rinse the sprayer. Do not flush Spinosad into creeks or ponds.
  • Thin and weed carrots.
  • Mow cover crop mixes in late vegetable plots when rye or wheat heads up, to help legumes develop.
  • Take rowcover from turnips that were sown 3 or more weeks earlier, to use on newer and more tender crops.
  • Till beds you’ll plant in a week or two, as heavy rain may prevent tilling close to sowing time. My ideal is to till as deep as needed ahead of time, then do a superficial tilling or scuffle hoeing the day before planting. This gives the best weed control.
  • Spread compost on beds you’ll plant in 3 weeks or so, and till in the compost when the soil is not too wet, not too dry.
  • If exposed to 10 consecutive days below 45°F (7°C), celeriac will bolt.
  • Store spring and fall seeds (spinach, peas, beets) in a cool place for the summer.
Vates kale outdoors. An oleracea type, Vates is very cold-hardy.
Photo by Nina Gentle

Special Root Crop Topic for April in Central Virginia: the Hungry Gap

What is the Hungry Gap?

The Hungry Gap happens in temperate climates with four seasons. In winter the short day-length reduces plant growth, and when it’s cold, maybe damp, windy, and overcast, the rate of crop growth drops further. The Hungry Gap is the annual period of the shortfall in local fruit and vegetables. April is the leanest month of the year in northern temperate climates, and the period can extend from January to May. This may be a factor in the origin of the 40 days of Lent.

Spring is not the time of overflowing bounty you might expect – leaves are growing, but not much else. Depending on your particular climate, there may be some vegetables that are winter-hardy. Almost every vegetable lover yearns for more variety than that!

In the spring, any remaining winter vegetables are getting ready to bolt (produce flowers and seeds rather than more leaves). Growers and gardeners are enthusiastically sowing and transplanting new crops, but planting too early would be a sad mistake and it takes time before those new crops can be harvested. That gap between the last of the winter crops and the first of the early spring crops, is called the Hungry Gap.

It’s not a familiar term these days, because importing produce from warmer climates hides the reality. Vegetable consumption in much of the Western hemisphere has shifted from Medieval (leaves and roots) to Mediterranean (“ratatouille vegetables” and salads). Importing or long-distance hauling demands more energy usage, as does the refrigeration they often require in transit.

Also there has been a practice of growing vegetables with artificial heat and light. This is not ecological, as use of fossil fuels contributes to climate change. The food sector accounts for 30% of global energy consumption and produces about 20% of GHG emissions (see the 2011 FAO report). Most of this energy consumption comes from oil and gas in the form of artificial fertilizers and pesticides, on-farm machinery and food processing.

Sweet Potatoes in storage.
Photo Pam Dawling
Sustainable Ways to Bridge the Hungry Gap

How did people survive the hungry gap in times gone by, and what can we learn from those strategies? Eating in the hungry gap used to be both hard and uninspiring – a restricted diet with few options. Adding options involves advance planning and advance work.

  1. Use stored food, such as root crops, winter squash and pumpkins
  2. Preserve fruits and vegetables from other seasons. Consider jams, pickles, canning in jars, freezing, drying, salting and fermenting (think sauerkraut)
  3. Grow more winter-hardy crops that start regrowth early in the spring, and may be harvestable during the winter. Consider covering the rows with rowcover or polyethylene low tunnels.
  4. Grow more perennial crops, such as asparagus, rhubarb, sea kale and sea beet (Beta vulgaris subsp. Maritima, wild beet). Although they take several years to establish, they will then yield earlier in the year than crops grown from seed in spring. Asparagus and rhubarb provide new flavors early in the year and signal the change to come.

    Asparagus in early April.
    Credit Wren Vile
  5. Sow fast-growing cold-hardy crops as early as possible after the winter solstice, for example spring leafy vegetables such as spinach, kale, collards, fast cabbage varieties, and lettuce.
  6. Add crop protection in the form of rowcovers, low polyethylene tunnels (cloches), caterpillar tunnels, high tunnels (hoophouses, polytunnels) to create a warmer environment, trapping heat and humidity and warming up the soil, providing earlier harvests. Protect early sowings of quick crops, like radishes, arugula, land cress, salad greens, and also the first few weeks of newly planted kale, collards, spinach, mizuna, pak choy).
  7. Forage sustainably for edible wild greens as a spring ‘tonic’, even if not a major item in your diet. The strong flavors provide a welcome change after repetitive winter vegetables, and a useful top-up to the supply of produce as stores run low. Spring is one of the best seasons for foraging, but you do have to reliably identify what you’re picking, so get yourself a good guide book or phone app. Ramps, nettles, violets, chickweed, dandelion, garlic mustard, and lamb’s quarters are some of the many wild greens available in spring. See Rustic Farm Life: Wild Spring Greens You Should Be Eating

    Ruby chard.
    Photo Kathryn Simmons
  8. Maximize the number of annual and biennial crops you grow that are in season during the Hungry Gap. Some are mentioned already. Here are more ideas: chard, globe artichokes, herbs, Jerusalem artichokes, kale (one variety is called “Hungry Gap” because it crops during this period. It was introduced to UK agriculture during WWll in 1941), leeks. If your winter climate is mild enough (zone 8 or 9): over-wintered Purple sprouting broccoli, and spring greens (immature close-spaced dark-green cabbages).

    Brassica oleracea ‘Hungry Gap’ – kale
    Photo Chiltern Seeds, UK
  9. Indoor gardening. Grow sprouts and microgreens. These don’t take much advance planning and can perk up a winter or spring meal. Microgreens grow in compost or on special “blankets”, but sprouts are generally grown in jars or trays. Pea shoots are an easy one to start with, and you can use dried peas from the supermarket. When sprouting it is important that you buy organic seeds, to be sure that they have not been treated with any chemicals. Rinse your sprouts twice a day, and keep everything clean.

Read more about the Hungry Gap

https://www.youtube.com/watch?v=FbZfTAYDA88

https://theunconventionalgardener.com/blog/what-is-the-hungry-gap/

https://sustainablefoodtrust.org/articles/spring-plate-eating-hungry-gap/

https://www.farmdrop.com/blog/hungry-gap-seasonal-british-produce/

This is the last post in the monthly series on root crops. You can see them all here:

Root Crops in May

Root Crops in June

Root Crops in July

Root Crops in August

Root Crops in September

Root Crops in October

Root Crops in November

Root Crops in December

Root Crops in January

Root Crops in February

Root Crops in March

Workhorse Crops for the Month

Next month I will start a new monthly series. Workhorses are crops that are reliable under a wide range of conditions, including weather, soil, date and other variables. Some are easy to grow, some pump out lots of food, some are “insurance crops” like chard that stand in your garden until you need to harvest them. Part of my motivation for this series is to help all the “Covid-steaders” who started growing food during the pandemic and want to up their game without investing a lot more time. Part is to help established gardeners and growers who need to make a living while dealing with the changes the past year has brought to their markets and to our climate. We need some easier days!