For October, I’m writing about ramps. October is a good time to plant ramps bulbs and seeds. Bulblets are better planted in early spring. Ramps thrive in USDA Winter Hardiness Zones 3-7. Some of this material is from my second edition of Sustainable Market Farming, and the sources quoted here.
Today, ramps are a wild-edible delicacy in most places and defines a sort of Appalachian or Eastern U.S. “terroir”, but what was once a commonly found plant is now a rarity as land development and sprawl, deforestation, and over-harvesting by some foragers has decimated the population.
Ramps, (Allium tricoccum) (aka wood leeks or wild leeks) combine some of the flavors of leeks, onions, and garlic. They are a traditional and newly fashionable food. Ramps are a native woodland perennial that can be wildcrafted sustainably or raised in a suitable woodland.
“The ramp has broad, smooth, light green leaves, often with deep purple or burgundy tints on the lower stems, and a scallion-like stalk and bulb. Both the white lower leaf stalks and the broad green leaves are edible. The flower stalk only appears after the leaves have died back, unlike the similar Allium ursinum, (Ramsons) in which leaves and flowers can be seen at the same time. Ramps grow in close groups strongly rooted just beneath the surface of the soil.” – Cultivation of Ramps, North Carolina State University
It takes a ramp plant 7 years to reach sexual maturity from seeds and produce more seed. The plants are mature when their leaves reach heights of 6”-8” (15-20cm). From planting bulblets it takes 3-5 years to reach harvest size. So I’ll start by explaining how to wild-craft the leaves, then move on to info on establishing your own ramps.
Ramps research NC State ramps harvest study Jeanine Davis program, 2022
Harvesting ramps leaves
Ramps are a spring ephemeral of deciduous forests that can be wild-harvested sustainably for 1 month in the eastern half of the US and Canada, starting when tree buds appear. By late May, the leaves yellow and die back, and a flower stem emerges.
Wild ramps are being over-harvested, and it is important to make sure that not all these wild culinary delights vanish and they are still able to find their way onto plates in a sustainable fashion. Take only what you can use in a few days. Only 5% to 10% of the ramps in a patch should be harvested each year to ensure their future survival. The most sustainable harvest method is to cut only one leaf, leaving the bulb and second leaf to continue growing. Before harvesting from public lands, check local regulations. There may be limits on where, when and how much.
There are some toxic look-alikes so be sure the plants you pick smell like onion or garlic. If you’re unsure, let a knowledgeable forager confirm your find or just don’t pick them. Do not pick Lily of the Valley (Convallaria majalis) or False hellebore (Veratrum genus) by mistake.
Harvesting the leaves with bulbs attached is also possible, if the area has plants to spare. To harvest, use a sharp strong knife, such as a hori-hori and slide it into the soil at an angle. Cut the bulb just above the roots, and leave those in the ground to regrow. Take only the leaves and bulb. Some say a wildcrafted whole ramp (with bulb intact) is never a sustainably harvested ramp. Bulbs can be frozen for later use.
See the videoHow to Sustainably Harvest Ramps from Carriage House Farm.It uses a similar knife technique but removes only stem and leaves.
To get started, you can buy seeds year-round, bulbs in September and October, and bulblets in late winter at Gates Hill Farmrampfarm.com. Once you have established some plants, you can divide and replant annually.
There are about 50 seeds per ounce, roughly 2 per gram. Ramp seeds require a warm period followed by cold stratification to break dormancy. If there is not an adequate warm period after sowing, the seed stays dormant until the second spring. This explains the wide range of 6-18 months to germinate ramp seeds. It’s easy to see how wild ramps get seriously over-harvested.
Collect ramp seeds in August and September
If you were wild-crafting ramps in spring, late summer/early fall is time to pay the piper. Collect seed and scatter it over the patches you dug from. Or collect seed to grow in woodlands at home – without of course, taking too many away from a place they could grow naturally.
Establishing a ramp planting
Ramps grow best in deciduous woodlands with adequate moisture. There are projects to re-establish ramps in a number of regions in the Eastern United States.
NC State Extension, Cultivation of Ramps (Allium tricoccum and A. burdickii) Revised 2025, has lots of reliable information on cultivation, harvesting, pests, and conservation status. This publication cites Forest Farming Ramps. Agroforestry Notes. AF Note 47. 2014. USFS. Although published in 2014, the plants grow the same way, and the publication has useful info on habitat, lifecycle, site selection and preparation for cultivation as a forest understory. The online links, are, naturally not much use now.
PennState Extension: Emerging Research on Ramps; Pugh, Cathryn, & Norman, Calvin. Ramps (Allium tricoccum). PennState Extension, 2023. psu.edu/ramps-allium-tricoccum Cathryn Pugh & Calvin Norman
Many other publications on tree crops, Key Perennial Crops, black walnuts, Asian pears, persimmons, honeyberry, mulberry, serviceberry, aronia, cider apples.
Much of this information comes from my book Sustainable Market Farming 2nd Edition.
This month, I’m writing about kohlrabi, an eye-catching and very storable brassica crop. Kohlrabi can be grown in central Virginia where I live in spring and in fall. In cooler climates it can be grown in summer, and in warmer ones through the winter. The winter-kill temperature for kohlrabi grown in the open, with no protection, is 15°F (–9.5°C), similar to red chard, Russian kales, and some varieties of beet, broccoli, cabbage. Kohlrabi production is like that of other brassicas, and the methods of cultivation and harvesting are very similar.
Kohlrabi is an unusual crop that is sure to attract attention at your market booth or be a discussion piece in CSA bags, in your garden and on your table. It is a swollen stem base, with leaves individually sprouting from the globe. When the tap root and leaves are trimmed off, it resembles a sputnik (the first manufactured Earth satellite, in 1957). It is tender and crunchy with a flavor between a cabbage and a turnip. It’s easy to grow and doesn’t wilt as soon as you harvest it. It can be eaten raw (sliced or grated) or cooked, and the leaves can also be cooked and eaten. It stores well, offering flexibility about when it is eaten or sold, which is always an advantage for growers.
Kohlrabi can be direct sown or transplanted, whichever suits you best.
Kohlrabi Crop Requirements
Brassicas grow best on fertile well-drained soil with adequate moisture. They require a lot of potassium, so a sprinkling of wood ash, kelp meal, or granite dust could be helpful if your soil is a bit short of potassium. Calcium, boron, iron, manganese, and molybdenum are also important for good brassica crops – healthy, biologically active soils can usually supply enough of all these. If not, amend as needed. Optimal growing temperatures for most brassicas are 60°F–65°F (15°C–18°C).
Because fall brassicas are transplanted in summer, it’s possible to grow another vegetable crop, or some good cover crops, earlier in the year. An overwintered cover crop mix of winter rye and crimson clover or hairy vetch could be disked in at flowering and followed by a short- term warm-weather cover such as buckwheat, soy, or southern peas, all before the fall kohlrabi. A spring-sown cover crop mix of bell beans (favas), barley, and oats does well before all fall brassicas at Roxbury Farm in New York, supplying all the nitrogen required by the brassicas, which are heavy nitrogen consumers. To minimize pests and diseases, don’t use brassica cover crops.
Rotations Including Brassicas
A rotation of 1 year in 4 is ideal for brassicas to avoid disease and pest buildup. When possible, plant one year’s brassicas at some distance from the previous year’s, rather than in adjacent plots. The spread of disease can be reduced by avoiding walking through wet crops and by controlling weeds in the brassica family, such as rock cress, pepperweed, garlic mustard, and wild rocket.
We always plant our kohlrabi in permanent raised beds as we cultivate these with a BCS walk-behind tiller and can work them a bit sooner than the flat fields, where we must wait for the soil to dry enough to use the tractor and disks.
Kohlrabi Varieties
Interest in kohlrabi is growing.I’m encouraged to see that Johnny’s now sells 7 varieties, Fedco has five, Baker Creekhas 6 and High Mowing has 8!
We like the open-pollinated Early White Vienna and Early Purple Vienna (58 days from sowing) and the purple hybrid Kolibri(45 days), which is more expensive but beautiful, quick-growing, and uniform. Purple varieties seem slightly more resistant to cabbage worm and also less susceptible to cracking. A mixture of the white (green) and purple colors looks very attractive, and they’re both white under the skin, so our strategy is to grow 25%–35% purple and mix them in; 4 g = about 1,275 seeds, sows 135′ (41 m). 5,500–9,000 (avg. 6,500) seeds/oz, (200–320, average 230 seeds/g).
Superschmelz kohlrabi (60 days from transplanting) can also be summer sown for fall harvest. It produces 8″–10″ (20–25 cm) bulbs, which are an attractive globe shape and remain tender. The world record (variety not disclosed) weighed almost 97 lbs (44 kg), leaves included.
Kossak (80d to maturity) is a good storage variety that maintains its sweet, delicious, and tender dense white flesh in storage for 2–4 months.
The other type of kohlrabi is the slower-growing giant winter storage variety, such as Gigante (130 days from sowing in spring for late fall harvest). It regularly exceeds 10″ (25 cm) in diameter and 10 lbs (4.5 kg) in weight. Gigante’s crisp, white, mildly tangy flesh doesn’t get woody even when it gets enormous.
A September sowing of kohlrabi. Too late in the year to thin and grow to full-size, kohlrabi makes good salad and microgreens. Photo Bridget Aleshire
How Much Kohlrabi to Grow
We grow 360 row feet (110 m) of fall kohlrabi for a hundred people. We sow in mid-late July, and transplant around July 29–August 12 at 8″ (20 cm) apart in the row, with 9″–10″ (23–25 cm) between rows – 4 rows in a 48″ (1.2 m) wide bed. If direct sowing, you could sow in drills or in stations (groups of several seeds sown at the final crop spacing).
Systems for Growing Kohlrabi Transplants
The same systems you use for growing transplants in spring may also work well for fall: flats, cell-packs, outdoor nursery beds. We use an outdoor nursery seedbed and bare-root transplants because this suits us best. The nursery bed is near our daily work area so we’ll pass by and water it. (Our greenhouse is off to one side of our gardens.) We’re always relieved to close the greenhouse transplant season in May, as we no longer need to water little plants many times each day to keep them alive. Having the seedlings directly in the soil drought-proofs them to some extent; they can form deep roots and don’t dry out so fast.
Other people manage fine with flats in June and July, but we avoid it. If you use flats, it can help to have them on benches in an enclosed shadehouse, or outdoors, above the height of flea beetles. Ira Wallace of Southern Exposure Seed Exchange tells me 3′ (1 m) is high enough. Richard Jones, in his book Beetles, says flea beetles can jump at least 100 times their body length.
For our seedbeds, we use insect netting (ProtekNet) on wire hoops. In warm weather, I prefer netting against bugs because it lets in lots of air. Rowcover also protects against bugs, but provides less airflow, which can make the seedlings more likely to die of fungal diseases in hot weather.
Kohlrabi is a less-common brassica. This is Early Purple Vienna. Photo Kathryn Simmons
Germination of Kohlrabi Seeds
The most challenging part of producing fall brassicas is getting the seedlings growing well while the weather is hot. Unlike some cool-weather vegetables such as spinach, brassicas will germinate very well at high temperatures: the ideal is 77°F–85°F (25°C–29°C), but up to 95°F (35°C) works. Given enough water, summer seedlings will emerge in only 3 days. Once they have emerged, the challenge begins. As well as temperature and moisture in the right ranges, the seedlings need light (very plentiful in midsummer!), nutrients, good air-flow, and protection from bugs. Guarding the plants from bugs is the most challenging for us. We deal organically with flea beetles, harlequin bugs, and, sometimes, cabbage worms. Our main defenses are farmscaping and insect netting.
Search my previous posts for more on pest control. Brassica pests seem less interested in kohlrabi than in other brassicas, and as people are less likely to eat the leaves, there is room to tolerate a certain number of leaf-eating pests, while still having an attractive crop and a high enough yield.
“No visible brassicas” month
In an attempt to break the relentless lifecycle of the harlequin bugs, we now try to have a month from late June to late July with no brassicas visible in our garden. We make sure to mow down the spring broccoli trunks, the kale, and collards and harvest or pull up any other brassicas. We net new transplants and remove the netting a month later, allowing us to hoe and weed.
Brassica seedlings under Proteknet. Photo by Bridget Aleshire
Timing for Fall Kohlrabi
Planting dates for fall crops can be exacting because the cooling weather slows down the plants’ growth, and a day or two delay in sowing date can mean a week or two delay in harvest date. Although it can be hard to think about sowing seeds in midsummer, it’s very worthwhile because brassicas develop delicious flavors as they mature in the cooler fall days,. Weeds and pests slow down then, too – once established these crops need little care.
The number of days to harvest given in seed catalogs is based on spring conditions – plants grow faster in warmer temperatures. To determine when to sow for fall plantings, start with your desired harvest date (noting when would be too late!), then subtract the number of days from seeding to transplant (21–28), plus the number of days from transplanting to harvest for that variety (given in the catalog description), plus the length of your ideal harvest period and another 14 days for the slowing rate of plant growth in fall compared to spring.
Example: Early White Vienna Kohlrabi, 58 days from sowing to harvest in ideal weather.
Consult https://weatherspark.com to estimate when it will get too cold in your location to leave kohlrabi in the ground. Here, in winter-hardiness zone 7a, our average annual minimum temp is 0°F-5°F (-15°C to -17.7°C), although most winters don’t reach those temperatures for very long. Our average winter low is about 25°F – 32°F (-4°C to 0°C).
Kohlrabi is hardy to 15°F (–9.4°C). The temperature is not likely to drop to 15°F (-9.4°C) before the beginning of December here.
Adding 40% more time, allowing 80 days, we could sow kohlrabi in early August and get a crop at the end of October.
Or mid-August for early November.
Or early September for the end of November or very beginning of December.
If you sow too late, use the seedlings for salad. Kohlrabi also makes a good microgreens crop.
Sowing Kohlrabi Seeds
Our rough formula for all transplanted fall brassicas is to divide our final crop row length by our in-row plant spacing and then sow extra to be sure of having enough good ones on transplant day. For kohlrabi to be planted 8″ (20cm) apart, to plant 360’ (110 m) we’ll need 540 perfectly lovely transplants.
We aim to sow 3 seeds/inch (1 cm apart). We make two sowings one week apart, to ensure we have enough plants of the right size. Each week after the first sowing, we weed the previously sown plants, and thin them to 1″ (2.5 cm) apart. We resow to make up the numbers if germination is low.
Young kohlrabi plants. Photo Kathryn Simmons
Transplanting Kohlrabi
We aim to transplant most brassicas at four true leaves (3–4 weeks after sowing). It is better to transplant crops at a younger age in hot weather than you would in spring because larger plants can wilt from high transpiration losses. If we find ourselves transplanting older plants, we remove a couple of the older leaves to reduce these losses.
We transplant in late afternoon or early evening. We water the soil in the plot if it is dry, because it is very important at this time of year to get adequate water to the plants undergoing the stress of being transplanted. Likewise, good transplanting technique is vital. With drip irrigation, you can more easily give a little water in the middle of each day, which will help cool the roots. With only overhead sprinklers, you may not have the option of watering every day.
Bed of young kohlrabi. Kathryn Simmons
Kohlrabi Harvest
Harvest storage kohlrabi while the anchor (tap) root is still round, before it begins to elongate. We harvest our Vienna kohlrabi from October 20 to November 15. For storage cut off the tuft of leaves at the top of the plant and also the wiry root. It’s easiest to cut a disc off the bulb rather than try to cut through at the point between the bulb and the wire, where it is very tough.
Kohlrabi Winter Storage
Kohlrabi can be stored in a refrigerator or refrigerator-like conditions such as a CoolBot, 32°F–40°F (0°C–5°C), 80%–95% humidity. Basically Cold & Moist. Kohlrabi stores well in perforated plastic bags in a walk-in cooler. In a plentiful year, we have eaten stored kohlrabi throughout the winter into early spring.
Cover of Beyond the Root Cellar by Sam Knapp
A Few More Good Resources for Storage Information
Beyond the Root Cellar: The Market Gardener’s Guide to Growing and Storing Vegetables for Off-Season Sales and Food Security, by Sam Knapp
It’s carrot planting time for many of us from spring to late summer, and many growers are searching my site for information. Here are quick links to all of my many carrot posts over the years. Inevitably there is some overlap.
After these links there are seasonal details on planting carrots.
Carrot Seed Viability: you may be wondering if you can still use the seeds leftover from last year. Carrot seeds are generally good for 3 or 4 years if you have stored them carefully. Click the link above to read Factors influencing seed viability and Seed germination testing
See my slideshow on Succession Planting. We sow carrots from mid-February to August. Here’s Video of me presenting Succession Planting for Continuous Vegetable Harvests ten years ago at New Country Organics (I’ve updated the presentation since then);
Sowing carrots: Surprisingly to me, I have not written much about sowing carrots in spring. From Root Crops in February: Carrots do very poorly with competition from weeds or too many other carrots. You can make use of the Stale Seedbed Technique, preparing the bed ahead of time, and flaming or hoeing one or more flushes of weeds as they germinate.
A young carrot bed in April, ready to hoe and thin. Photo Pam Dawling
Carrots are small seeds, needing a fine tilth (small soil particle size and good texture – not likely to crust or blow away). Good information on crop spacing for maximum yields, or biggest vegetables is in an out-of-print book, The Complete Know and Grow Vegetables by JKA Bleasdale, PJ Salter, and others. Buy it used.
For maximum total yield of carrots, they recommend 1.5” x 6” (4 x 15cm). You get medium-sized carrots. For early carrots go with 4 x 6” (10 x 15cm) to minimize competition and get rapid growth. If you want to have rows more than 6” (15cm) apart, calculate the area of these optimum spacings, then divide by your chosen row space. For example, if your rows are 12” (30cm) apart, the carrots can be as close as 0.75” (2cm) if total yield is more important than individual size, or 2” (5cm) for fast early carrots. We do five rows in a 4’ (1.2m) bed, so the rows are about 10” (25cm) apart, with the outer rows 4” (10cm) from the bed edge.
One of many wheelbarrows full of compost we spread every year. Photo Wren Vile
We aim to spread compost 4-6 weeks before planting, rototill 2-4 weeks before planting, and prep the bed a week or two before. This is more time than we allow later in the year, but in early spring it’s good to seize the opportunities that arise and not take the weather for granted.
This means in January we compost and till beds for our first two beds of carrots, to be sown February 14 and February 28.
In the first half of February we till and spread compost for more carrots (planting dates March 9 to 15).
In the second half of February, we compost the third carrot bed and till the ones we already composted.
Once we get to March, day length has improved and temperatures are starting to climb. There is a noticeable increase in the rate of germination and growth (unlike our February sowings, which are rooted in faith and optimism!).
In early March we till the third carrot bed.
All being well with the weather, we sow carrots #3 in mid-March
In late March, we sow carrots #4
Carrot beds in June. Bridget Aleshire
There’s also a full chapter on carrots with all my information in my book Sustainable Market Farming, 2nd edition. It includes info on varieties, and which types are better for which soils, pests and diseases, crop rotations, cover crops before and after carrots, and more.
Preparing for Carrot Sowing
Planning for a continuous supply; see my slideshow on Succession Planting. Carrots have a much longer window for harvesting than most carefully planned successions, so you can be a lot looser in your planting dates. Mainly, just grow enough! After the spring start-up plan, we sow carrots once a month in April and May. If we need to, we sow once a month in June and July, although summer-grown carrots do not taste as sweet as those grown in cooler weather. We finish with a big sowing at the end of July or early August, 10–12 weeks before the usual first frost, to be harvested in November and stored for winter eating.
Decide how many to plant. Yield: 100 lb/100′ (150 kg/100 m), 30,000 lb/acre (34,000 kg/ha)
Calculate the amount of seed required; Carrot seeds are 175,000–600,000 (avg. 288,000)/lb, 18,000 seeds/oz, 625 seeds/g. 3,000 seeds (0.2 oz, 6 g)/100′ (30 m), 1 seed/cm. 625 cm/g, 600’/oz, 9,600’/lb, 2.5 lb/acre (at 30 seeds/ft in rows 24″ (60cm) apart). 720,000 seeds/acre.
Success with Planting Carrots
Before you plant, understand soil temperature requirements: Use a soil thermometer! Flag its location so you don’t lose track of it! Measure at 4″ (10 cm) deep at 9am. Carrot emergence takes3 days at 50°F (10°C), 10.1 days at 59°F (15°C), 6.9 days at 68°F (20°C), 6.2days at 77°F (25°C), 6 days at 86°F (30°C)and 8.6 days at 95°F (35°C).
Soil thermometer. Worth its weight in gold.
Old books warn against using manure before sowing carrots as it will make them fork. This refers to uncomposted manure, not compost. Compost will increase yields and even reduce the culls with some varieties (research by Dan Brainard and Corey Noyes, at Michigan State University). Compost not only increases the organic matter in the soil but also suppresses some diseases and nematodes (which can cause forked carrots)
Seed spacing and depth: for carrots, aim to sow 30 seeds/ft (1/cm), only 0.25″–0.5″ (0.6–1.2 cm) deep. Close the furrows and tamp down the rows with the back of a hoe or rake. The goal is to get good contact between the seed and the soil. Keep the soil surface damp until the seedlings start to emerge.
We sow a few Indicator Beets at the beginning of the bed. Beets germinate
We sow “indicator beets” with our carrots so that we know when to flame-weed them Photo Kathryn Simmons
one day sooner than carrots at almost any temperature. When we see the red loops of the beet stems emerging, we know it’s the day to flame weed the carrots. (From Workhorse Crops for March)
Carrots do very poorly with competition, so try to start early carrots in a bed that had only light weeds the year before. Later sowings can make use of the stale seedbed technique, where the bed is prepared ahead of time and one or more flushes of weeds are germinated and flamed or hoed off.
Carrot row thinned to 1 inch. Kathryn Simmons
Growing Great Carrots: Thinning and Weeding
Remember to thin carrots as soon as you can see them well enough to do so. We usually hoe between the rows first, then crawl along thinning and weeding. It does take time! But you won’t get good carrots without thinning, unless you either have a precision-seeder that drops one seed per inch, or pelleted seed which you can sow at one per inch.
Precision seeders like the Jang are expensive, but worthwhile if you need to use it every week. Pelleted seed costs more than raw seed, and its big advantage is traded off for two other disadvantages: The soil has to be kept well-watered until germination or else the clay coating will imprison the seed forever, and the seed does not store for long – don’t keep any over for next year.
It pays to sow in parallel rows an even distance apart. This makes for fast and effective hoeing with fewer mistakes.
Beyond the Root Cellar: The Market Gardener’s Guide to Growing and Storing Vegetables for Off-Season Sales and Food Security, Sam Knapp, 2024, 272 pages, 8 x 10 inches. $45. Chelsea Green Publishing.
Cover of Beyond the Root Cellar by Sam Knapp
I have been looking forward to this book, because I appreciated several articles by Sam Knapp in Growing for Market magazine. This book addresses a gap in most local food systems. It is the first (only) book of this kind, and it’s very good. Sam Knapp is a pioneer.
Sam worked as an engineer before becoming a farmer in the Michigan Upper Peninsula, and then in Fairbanks, Alaska, where he runs a winter-only CSA from Offbeet Farm and sells to local groceries. Thanks to his scientific background, he understands and explains energy efficiency, as well as spreadsheets, very well.
This book will up your game in storing winter vegetables, as it includes the vital information on choosing, growing, harvesting, trimming, processing, curing (if needed) and storing eighteen crops, as well as details about constructing storage spaces and operating climate-control systems.
The author has considered lots of sources of information, and when information conflict, he has presented the experience of farmers, and the results of scientific trials and studies. There’s plenty of useful info for small scale growers not on the point of building big storage buildings. Anyone growing any storage vegetables will get valuable information.
North American countries could use a lot more locally grown winter crops. There is not much competition yet. A storage farmer wanting to also provide training for apprentices, or other ways of training, would be offering a rare commodity.
Harvested turnips ready for storage. Photo Pam Dawling
Storage crops offer a lifestyle of intense large-scale work in the fall, followed by a “selling season” with reduced or no outdoor work. Storage crops take a little time to plant and tend during summer, leaving lots of the week open for other activities. The work flow is less likely to cause burnout than farming for summer and fall sales.
The first part of the book (about 60 pages) is From Field to Storage. Here we learn about choosing appropriate crops and varieties, recognizing maturity, harvesting, post-harvest handling and putting the produce into storage. The author’s father Phil spent many weeks of his retirement taking the photos for the book, as well as helping with construction work. The uncorrected proof I am reviewing has the photos rendered in greyscale, such is the lot of reviewers!
Some vegetable crops increase their cold-hardiness as daylight and temperature decrease by producing sugars and alcohols in their cells, lowering the freezing point of the sap. Others transition to a state of reduced metabolic rate, activated by plant hormones or low temperatures. There are two kinds of dormancy: hormonally controlled dormancy and environmentally controlled dormancy. The latter crops will sprout if exposed to warm temperatures and moisture. Crops with hormonally controlled dormancy will not resprout until triggered by a change of hormones, often due to cumulative exposure. Aha! New information for me. Which crops are which? Sweet potato dormancy is environmentally controlled. Any extended exposure to moisture and temperatures above 60F (15.5C) leads to sprouting. Potatoes, on the other hand, can stay dormant for months even if exposed to good growing conditions. Onion sets are an example of dormancy maintained by environmental conditions – temperatures above 85F (29C), and dry. Onion sets when planted in cool spring conditions, grow into larger onions.
South Anna Butternut winter squash, a Moschata bred by Edmund Frost to resist Downy Mildew Photo Southern Exposure Seed Exchange
Choose crops that reliably mature in your area. The number of frost-free days, soil temperatures and daylength can all affect maturing. Did you know that Butternut squash requires darkness to set fruit? Avoid crops or varieties that easily bolt, split, break, or bruise, or are susceptible to rots. Read the small print in the seed catalogs. Collect your own data, perhaps on your phone. The book has some tips and a Variety Trial Datasheet. Record storable yield per area, as well as culls as a percentage of total yield.
The next chapter is about harvest. As this is going to be a major part of the farm work, Sam advocates careful harvest planning. There are charts in the book to help you track progress. Consider your last date for harvesting each crop, and the amount of time the harvest could take. Make sure not to plant more than you can harvest in the window! Make use of any past harvest records you have. Ask nearby vegetable growers too. Can you harvest 10 100ft x 5ft beds of cabbage in just over one day? How many days do you need to allocate to carrots? Can 2 people hand-harvest 900lbs of carrots in 8 hours?
Past climate data are helpful. The National Weather Service has a Past Weather page. (I like Weatherspark myself.) Look for daily normal, average high, low and mean temperatures for each day at that time of year. Plan to harvest before the date when the mean temperature reaches the threshold for chilling injury of that crop. It may well be earlier than you had expected. Remember to factor in some days for bad weather! Add rowcover or mulch in the fields if you need to buy time. Watch the crops and triage if necessary. This means three categories: crops it’s imperative to harvest, ones you must let go of, and ones to harvest if at all possible.
Bulb onions curing on a rack. Photo Wren Vile
Garlic and onions will most likely be first, and are very prone to troubles if left too long in the field. Cold-sensitive crops are next: winter squash, pumpkins and sweet potatoes. These all accumulate chilling injury below 50F (10C), leading to deterioration in storage. Next are the crops that are damaged by hard frosts: cabbage, kohlrabi, rutabagas, turnips, winter radishes, beets, celeriac, potatoes. Beets lead this group. The final group includes crops least damaged by hard frosts: carrots, parsnips, sunchokes, leeks.
Try not to be Nervous Nellie, harvesting sooner than necessary: many crops develop better flavors in colder weather. Also consider the extra electricity you’d use for cooling for longer. Common advice sets 28F (-2C) as the limit for intermediate crops such as beets, and 24F (-4C) for the most cold-hardy crops. The duration of cold temperatures as well as the daily mean, (and therefore the high temperature that day) are important parts of the equation.
There is some discussion of harvesting equipment, from knives to the intriguing Scott Viner harvester, which runs a digging shoe below a row of roots such as carrots, at the same time as a set of rubber belts grabs the carrot tops just above the crowns, and lifts them up, dangling by their tops. Next there is a knife that cuts the tops and deposits the carrots onto a chain conveyor, shaking soil off as it goes. The carrots are dropped into a following truck or wagon. A fast hand-worker can harvest 200-250lbs carrots per hour on a clean bed that has been undercut. A Scott Viner with 3 or 4 workers to tend it, can harvest 2,500 to 3,000 lbs per hour. Dryish soil is needed.
Harvest-handling equipment consists of containers and compatible equipment to move the filled containers. Carts and wheelbarrows can move about 200 pounds of well-balanced crops. Containers are generally either small enough to lift by hand or large enough to need a forklift. When considering upgrades, decide your handling equipment first, and get containers that fit with those.
Sweet potato harvest with carts. Usually we use a truck! Photo Nina Gentle
After harvesting, the crops generally need attention before storing: trimming, washing, curing, grading. There are several reasons for trimming root crops. Most leaves will rot in storage anyway, so they have no future. Trimming saves storage space, makes washing easier, and reduces moisture loss. Ideally, leave only short stubs of the leaf stems, which will dry out quickly and are unlikely to rot. If the trimming can be done in the field, all the inedible organic matter of that crop returns to the soil, plus you have less to haul away.
Potatoes and sweet potatoes must be cured, a process when cut surfaces heal over and become coated by a protective waxy layer. Cured skins become more firmly attached to the tubers, preventing further damage.
There is discussion on whether to wash root crops before storage. It depends on the equipment you have. With electricity, washing pre-storage is a viable option. Without it, conserve moisture in the veggies by leaving the soil on them. If you have cooled storage, you may prefer to wash veggies while the weather is warm, and the soil is easier to remove. Barrel washers are discussed, including farm-made ones, both hand-cranked and electrically powered, and purchased small-scale models.
Chapter 4 Into Storage contains lots of useful tips. In the first few weeks after you store the crops, they need attention to ensure conditions are right, and removal of vegetables that are starting to rot. You can’t sort through large amounts, but cast an eye over the top layer. Sam divides crops into four groups according to optimal storage conditions. He acknowledges that you might have to compromise if you can’t provide the ideal for everything.
Our root cellar. Credit McCune Porter
The cold and damp group (32F, over 98% humidity) works well for most winter storage crops, especially roots and leafy crops. Alliums do best at 32F and 60-70% humidity, fairly cold and fairly dry. Compromise on the temperature, not the humidity! Avoid 40-50F for garlic, and 50-86F for onions. Potatoes do best at 38-45F and above 95% humidity, as temperatures below 38F can cause chilling injury, leading to browning of the flash when cooked, especially fried. Higher temperatures lead to faster sprouting. Sweet potatoes are best at 57-60F and 85-90% humidity, and colder temperatures lead to chilling injury; higher ones to sprouting. Winter squash and pumpkins do best at 50-55F and 50-70% RH: higher temperatures lead to shriveling and yellowing of green varieties; chilling injury shows as pitted skin.
Choose storage containers that allow airflow, can stack, are not too heavy. Large farms use palletized containers. There are plastic macrobins, farm-made wood bins and cardboard Gaylord boxes with wood pallet bases. There are woven super sacks that fit on a pallet and can be lifted with pallet forks using the large loops at the top. These are cheap but don’t stack unless put inside a container such as an Intermediate Bulk Container (IBC) frame.
Alternatives are smaller containers such as 5-gallon buckets, plastic 18- and 27-gallon totes with holes drilled in them, as well as 50lb grain bags. This chapter has a chart of bulk density of storage crops, to help with planning. A 27-gallon tote can hold 95-110lbs of beets. Traditional storage methods such as damp sand or sawdust are fine for a few hundred pounds of veggies, but impractical for large quantities. Also, sawdust, burlap, wood shavings and peat moss can impart their flavor to the vegetables.
Vegetables in our walkin cooler. Photo Twin Oaks (Renee)
Part 2 of the book (about 60 pages) covers designing structures and practices, including the business side. Starting a storage farm does involve high up-front costs for buildings and equipment, although it’s fine to start with the buildings you have. Efficiency, efficacy and scale are important, because storage crops don’t generally sell for top prices, although on the plus side, you will be selling into a relatively open market. Be sure to match the scale and costs of your infrastructure and production with your likely sales. Small intensive farms (1-7 acres of storage crops) with close crop spacing can produce high yields, such as 25,000lbs/acre. Average yields are 10,000lbs/acre for larger mechanized farms.
This book provides up-to-the-minute details on modern construction and insulation materials. It’s not a construction manual, more a technical decoding guide and a shopping advisor, providing the overview you need to have useful conversations with contractors. Or perhaps to provide the knowledge to embolden you to construct your own storage spaces.
There is help with estimating seasonal income and losses (there is are charts of shrinkage estimates over various durations). There are suggestions on how to sell crops before the storage losses become too high: figure out a percentage loss to accept, and if you still have produce at that point, put it on sale! And adjust your plan to grow less of that crop next year. There’s an excellent working example of squash loss. Note harvest weights, sales records, total losses, the selling quality and the effectiveness of your sales strategies. Don’t neglect other goals and ethics. Is your goal to maximize your income or to provide food for your community for as long as possible?
Traditional root cellars are useful. If you are starting from scratch, compare with shipping containers (either insulated or uninsulated and buried), walk-in coolers (used?), CoolBots, purpose built above-ground insulated buildings, or cellars below other buildings. Your climate will play a big role in choice of storage. Farmers with milder winters are able to manage with less-insulated structures, as their heating and cooling use will be lower.
This section includes explanations of R-value (insulation), dewpoint, temperature, relative humidity (RH), vapor barriers, various insulation materials, and which ones Sam recommends for various situations. There are instructions to slope floors, deal with joins in sheet materials, avoid thermal bridging, condensation and moisture transfer. Lots of help for those building their own structures or instructing a contractor.
Climate control is covered very thoroughly and clearly. Having a good storage structure gets you part way to your goal of keeping crops dormant while retaining moisture and limiting chilling injury. Refrigeration and/or heating might be required. There’s help with calculations and costs and choosing suitable equipment.
CoolBot controller
There’s a 3-page section comparing CoolBot (which uses AC technology) and commercial refrigeration. CoolBot has a limited range of operating temperatures. This might be sufficient if your climate is relatively mild, and you can use cold outdoor air most of the storage season. CoolBots don’t work so well with outdoor temperatures below 25F. Oversizing the CoolBot for the space or using multiple CoolBots in the same space will help with initial cooling of large harvests. Commercial refrigeration units can cool spaces faster than CoolBots. Single-AC CoolBot systems use less energy than refrigeration, but it’s unclear if multiple-AC systems do. CoolBot has a good website and customer service.
There are recommendations on dehumidifiers and humidifiers, not forgetting the “put water on the concreter floor” method. Good airflow is vital for achieving even conditions throughout your storage space: consider fans and pulling in cold outside air.
Part 3 (about 46 pages) is the storage crop compendium, where the needs of 18 storage vegetables are clearly described in precise detail, including responses to ethylene, and also common problems. This is the section I’m going to use immediately. If this is the only part of the book you need right now, buying the book is worth it! Sam has done a lot of sleuthing to compile very specific information. His longest storage recommendation seems to be 4-6 months, although longer is definitely possible in our climate.
Sam Knapp. Credit Martha Mintz
The final section of the book (about 65 pages) offers profiles of nine storage farms from North Carolina, Wisconsin, Washington, Michigan, Minnesota, Vermont, Manitoba and Alaska. Each profile ends with a paragraph of advice for new storage growers. These profiles make a good read, suggesting several workable systems, from ¼ acre improvised start-ups, through converted barn root cellars and dairy barns supplemented with refrigerated trailers or shipping containers, to purpose-built spaces on new farms requiring tree clearance or a set of walk-in coolers and trailers. Land in storage crops is up to 7 acres (25 acres in one profile) of storage crops, mostly grown on a bed system. Some use off-site rented storage. Most of the farms run CSAs and do a lot of harvesting by hand. Some focus on 8 or fewer crops, others diversify as much as possible. Some combine being a storage farm with growing summer crops, some specialize and some combine with farm-related businesses such as a fermentation business.
Carrot harvest cart. Our Danvers carrots have plenty of sturdy leaves to protect the soil over winter. Photo Mari Korsbrekke
At this time of year I think back over the past growing season and look ahead to what I might want to do differently next year.
We had our Garden Crop Review and talked about crops that did well.
Honey Boat Delicata from High Mowing
We all liked the Delicata squash (See my post of 9/4). Some of us thought we’d do better starting it later. We grew Honey Boat Delicata from High Mowing. This variety takes 100 days to mature if started early in spring. Less time if started later when the season has warmed up. This year we started them in the greenhouse 5/11, transplanted them 5/30 and we harvested the first flush of ours in August, which suggests it took considerably less than 100 days. We cleared the second flush September 4. In August we have lots of other crops to eat. We got about 250 6” (15 cm) squash from 50 plants, the low end of the advertised 5-10 fruits per plant. Ours had limited space, 2’ (60 cm) apart in the row.
If we direct-sow them outdoors next year in early June (when we used to sow our Halloween pumpkins), we could harvest them from early September to early October, when we start getting winter squash.
Rutgers 250-1 tomato. Photo Rutgers University
We grew Rutgers red slicing tomatoesagain, rather than Tropic, which had been splitting on us. Rutgers, of course, is bred for further north, so we might go back to Tropic if summers are too hot for Rutgers. the Rutgers also had a bit of scarring at the stem end that we were not big fans of. If you have a favorite red slicing tomato, please leave us a comment.
Green machine zucchini. Photo Johnny’s Selected Seeds
In the hoophouse we tried Green Machine zucchini for the first time. They did well. A 45d hybrid. Fedco’s 2019 trial of 20 modern zucchini varieties alongside the standard Raven. Green Machine was cranking out easy-to-pick beautiful dark zucchini with a mild nutty taste 7–10 days before Raven, purportedly a 48d hybrid. Raven was outproduced by Green Machine at a 4:1 ratio all season. Although not spineless, the open plant shape and wide branch spacing allows for quick picking of unscratched fruit. Tip-top disease resistance.
Lady Bell sweet pepper in our hoophouse. Photo Kathryn Simmons
We grew both Lady Bell (68d from transplanting to red) and Revolution (72 days from t/pl)) hybrid red bell peppers in the hoophouse. They seemed to yield equally well, with fruits of a similar size. Seed for Lady Bell is a lot more affordable than Revolution. Fedco bravely comments on Revolution: Expensive seed. No pretense there. What’s a poor farmer to do?
Fedco’s Red Dragon Chinese cabbage. 60d to harvest
We decided to try Red Dragon Chinese cabbage in the hoophouse this winter, and compare with our usual Blues Napa cabbage. But the seed packet went unnoticed in the tub, and we sowed it 9 days later than we planned to. As the Blues cabbage is maturing early due to a hot October, we might be glad of a later Chinese cabbage!
Common Wealth pickling Cucumber. Photo CW Growers
Outdoors we grew Common Wealth pickling cucumber as a slicer, and liked it very much. Sweet-tasting, crisp, thin-skinned, small-seeded, downy-mildew resistant, all round a great cucumber. Common Wealth Seed growers also sells a slicing cucumber DMR 401, a DMR 264 and South Wind, all good-sounding slicers, but I haven’t yet grown them.
Cow Horn okra pods. Photo Bridget Aleshire
Our Cow Horn okra did really well this year. Some years we have to replace lots of casualties. We had a hot week at the end of June, which brought in our okra 7-10 days earlier than usual. Probably we’d do better to use soil temperature and weather forecasts to decide when to transplant them.
Rhone lettuce. Photo High Mowing Seeds
Of the new lettuces we had this year, Rhone and Skyphosstand out. Skyphos is a big beautiful red butterhead with a bright light green center. Rhone is one of themultileaf types.It has angular pointed leaves in an interesting cherry-bronze color at the tips and green at the leaf bases. We have large drifts of it in our hoophouse this winter.
Memories of Mona cosmos. Photo Southern Exposure Seed Exchange
We discovered that celosia Tall Menagerie Mix and Memories of Mona cosmos are very good pollinator-attracting flowers. We’ll do more of those next year. We planted some extra-early borage for some friends’ wedding. It didn’t bloom in time, but once it did, it self-sowed and we got lots of volunteers, still flowering at the end of November. I might move one or two into the hoophouse for the winter, to attract beneficial insects there.
Young Cylindra beets. Photo Wren VIle
We learned the value of pre-soaking beet seed for an hour or two, in helping germination. One planting that didn’t get any soaking failed to emerge. Other years we’ve learned the value of not soaking beet seed for too long, as it drowns. We aim for Not too dry/Not too wet/Just right!
grape trellises and solar panels in the mist. Photo Bridget Aleshire
Last week I wrote about how useful our two large solar arrays have been during the late unseasonably hot weather, to shelter our cattle in their thick winter coats. At the same time my county, Louisa County, Virginia, has been considering various zoning and planning requests for more solar farms. I’m a fan of solar power, but I’m horrified at how much good farming and forestry land is headed towards becoming solar farms. We also need food! Trees are important carbon sinks!
The inaugural Virginia Association for Biological Farming-Small Farm Outreach Program Summit 2024 brings together farmers, gardeners, eaters, educators, industry professionals, and advocates of sustainable, biological, regenerative, and organic agriculture!
The three day Conference includes: Full and Half Day Pre-Conference intensive workshops, 60+ sessions and workshops, presentations and panel discussions, 40+ tradeshow exhibitors, locally sourced farm meals and book signings. The Conference features a Youth & Teen Program, a Silent Auction and networking opportunities including regional networking meetings, and the Taste of Virginia Expo & Social!
Jean-Martin (JM) Fortier is an organic farmer, author, educator and internationally recognized advocate for regenerative, human-scale and profitable agriculture. JM Fortier founded the Market Garden Institute. He is the author of The Market Gardener, and co-author with Catherine Sylvestre of the Winter Market Gardener. His presentation is Friday 1-5 pm.
We regret to inform you that Niaz Dorry has had to cancel her keynote speech due to understandable personal reasons. Fortunately, she has kindly connected us to another exciting speaker, Ray Jeffers.
Ray Jeffers
Ray is a native of Person County, NC, where he also operates the family’s century farm purchased by his great-grandfather in 1919. Previously Ray served for 12 years as an elected Person County Commissioner (2008-2020), and was most recently elected in 2022 to the North Carolina House of Representatives where he serves on the Agriculture committee. Ray continues to serve on several local and state boards promoting agriculture and rural communities. Ray attended Piedmont Community College and North Carolina Agricultural and Technical State University.
B. Ray Jeffers joined the RAFI-USA team in June 2021 and near the end of 2022 became Director of the Farmers of Color Network. Ray is no stranger to the job as he currently grows seasonal vegetables for wholesale and direct sale at his B.R. Jeffers Farms in Roxboro, NC, as well as raises heritage breed hogs for direct sale at markets and restaurants.
We’re excited and grateful to have Ray join us for Part 1 keynote address during Saturday evening and a Part 2 keynote address during Sunday lunch.
7 Full and Half-Day Pre-Conference workshops and a farm tour are available on Friday, January 19. In 2024, thanks to grant funding from USDA-NOP-TOPP and a sponsorship by Sand County Foundation, all workshops and the farm tour are being offered free of charge to VABF-SFOP Summit attendees. Workshops may be added on free of charge to your Summit Registration. Spaces are limited.
The Full Day Workshop, Holistic Farming Methods: How Organic, Biodynamic, Permaculture, & Beyond Integrate for a Sustainable Future, includes the Hotel Lunch Buffet free of charge. The Lick Run Farm Tour includes a bagged lunch on the farm. All other pre-conference workshops have the option of purchasing the Hotel Lunch Buffet for $35.
on Friday 1/19, 9 am to noon,I am presenting a half -day workshop: Year-Round hoophouse Vegetables
Hoophouse with winter crops
Fill your hoophouses (high tunnels, polytunnels) all year round with productive crops. In this course you’ll learn how to decide which crops to grow—with an emphasis on vegetables—how much to plant and how much to harvest by making maps, schedules and crop rotation plans. We’ll discuss which market crops are best at various times of year—cold-hardy, early warm-weather and high summer crops—and consider less common crops, such as seed crops and flowers, and cover crops for soil improvement. Learn how to maximize the use of space by clever seasonal transitions, succession planting and follow-on cropping. The course will also provide strategies for managing challenges such as extreme temperatures, nitrate accumulation in leafy greens, soil-borne diseases, pests and nematodes, salt buildup, and maintaining soil organic matter.
Explore the conference schedule and see when different sessions will be held.
On Saturday 1/20, 4-5.30 pm, I am presenting Storage Vegetables for off-season sales, in the Buck Mountain Room.
Our winter squash storage cage. Photo Twin Oaks Community
Grow crops you can sell during the winter, while allowing yourself some down-time and reprieve from outdoor work. Choose suitable crops, schedules and storage conditions. Understand your weather and basic crop protection. This workshop will provide tables of cold-hardiness and details of four ranges of cold-hardy crops (warm and cool weather crops to harvest and store before very cold weather; crops to keep alive in the ground further into winter, then store; hardy crops to store in the ground and harvest during the winter, and overwinter crops for early spring harvests before the main season). It includes tables of storage conditions needed for different vegetables and suggestions of suitable storage methods, with and without electricity.
On Sunday 1/21, 8.30-10 am, I am presenting Lettuce Year-Round, in the Mill Mountain Room.
Buckley One-cut (Eazileaf) lettuce. Photo High Mowing Seeds
This presentation includes techniques to extend the lettuce season using rowcover, coldframes and hoophouses to provide lettuce harvests in every month of the year. The workshop will include a look at varieties for spring, summer, fall and winter. We will consider the pros and cons of head lettuce, leaf lettuce, baby lettuce mix and the newer multileaf types. Information will also be provided on scheduling and growing conditions, including how to persuade lettuce to germinate when it’s too hot, and the Asian greens used as lettuce in tropical climates.
Included in the Conference Registration and free and open to the public is the Taste of Virginia Expo & Market on Saturday, January 20, 2 – 9 PM in the Crystal Ballroom at Hotel Roanoke. Featuring sampling and sales of Virginia-crafted foods, local libations, handicrafts, and herbals. Complete the evening with music, dancing, and socializing from 8-10 PM.
VABF is offering a Youth Program for children ages 5 – 12, and a special teen program for 12-18 year olds for only $60, including Saturday lunch and dinner and Sunday lunch . Youth Program Registration is offered as an add on to Conference registration or as a stand alone registration.
Rooms in the VABF room block at Hotel Roanoke are $135 + tax a night. Rooms may be booked online here or by calling (540) 985-5900 (or toll free at 866-594-4722) between the hours of 8am-5:30pm Monday – Friday and say you’re with the VABF Room block. Cut off date is Friday, December 29, 2023.
Always a fun experience to bid on unique and useful farm and garden products! If you have homemade gifts, books, or items on your farm that you no longer need that may be valuable to someone else, bring them on to the Silent Auction at the Conference! Great way to donate to VABF!
Locally Sourced Meals
VABF is working to procure the majority of our Conference food from local member farms. We look forward to supporting our member farms and enjoying delicious, fresh, local food from the farms below! All Conference Registrations include lunch and dinner on Saturday, lunch on Sunday and morning coffee and tea.
On Thursday February 8, 4-5 pm, I am presenting Storage Vegetables for off-season sales
Sweet potatoes crated in the field. Photo Nina Gentle
Grow crops you can sell during the winter, while allowing yourself some down-time and reprieve from outdoor work. Choose suitable crops, schedules and storage conditions. Understand your weather and basic crop protection. This workshop will provide tables of cold-hardiness and details of four ranges of cold-hardy crops (warm and cool weather crops to harvest and store before very cold weather; crops to keep alive in the ground further into winter, then store; hardy crops to store in the ground and harvest during the winter, and overwinter crops for early spring harvests before the main season). It includes tables of storage conditions needed for different vegetables and suggestions of suitable storage methods, with and without electricity.
On Saturday, February 10, 11.30 am -12.30 pm, I am presenting Crop Rotations for Vegetables and COver Crops
Crop Rotation Pinwheel
This workshop offers ideas to design a planting sequence that maximizes utilizing cover crops and reduces pest and disease likelihood. Pam discusses formal rotations and ad hoc systems for shoehorning minor crops into available spaces. She also discusses cover crops suitable at various times of the year, particularly winter cover crops between vegetable crops in successive years. Pam provides examples of undersowing cover crops in vegetable plantings and no-till options.
In addition to my sessions, you’ll find 70+ other workshops and discussions on a diverse array of farming and food system topics:
Keynote Speaker Reginaldo Haslett-Marroquin
Plenary keynote speaker Reginaldo Haslett-Marroquin is a farmer and the founder of the Regenerative Agriculture Alliance, a non-profit organization focused on scaling up a systems-level regenerative poultry solution that restores ecological balance, produces nourishing food, and puts money back into the hands of farmers and food chain workers. He is also the co-founder and CEO of Tree-Range® Farms, the for-profit market-facing arm of the system working with family farms to raise chickens in their natural habitat—the jungle!
Dr Heber M Brown
Rev. Dr. Heber M. Brown III, another plenary speaker at this year’s conference, is a pastor, public speaker, community organizer, and social entrepreneur. He is the founder of the Black Church Food Security Network, which advances food security and food sovereignty by co-creating Black food ecosystems anchored by Black congregations in partnership with Black farmers and others.
Ira Wallace
Other featured speakers include Ira Wallace of Southern Exposure Seed Exchange, Zach Loeks of Ecosystem Solution Institute, Catherine Sylvestre of Ferme des Quatre-Temps, Allyson Levy & Scott Serrano of Hortus Arboretum & Botanical Gardens, Russ Wilson of Wilson Land & Cattle Co. and the FairShare CSA Coalition.
The Winter Market Gardener: A Successful Grower’s Handbook for Year-Round Harvests, Jean-Martin Fortier and Catherine Sylvestre, New Society Publishers, October 2023. 256 pages, 7.5 x 9 inches, with color photos and drawings throughout. $39.99.
Jean-Martin Fortier’s first book, The Market Gardener, is a well-loved international best-seller. In this new book, he has worked with Catherine Sylvestre, to focus on cold-weather growing. Catherine is the director of vegetable production and leader of the market garden team at la Ferme des Quatres-Temps, in Hemmingford, Southern Quebec, Canada. The farm includes mixed livestock, an orchard and an 8-acre market garden designed and established by Jean-Martin Fortier. FQT was initiated by a local multi-millionaire who wanted to set up an experimental farm to demonstrate what was possible and to resolve some of the challenges in developing a diversified farm using efficient regenerative methods. The farm now has a second site, in Port-au-Persil, five hours away in the northern Charlevoix region.
At FQT, the authors train cohorts of employees and try out ideas that were not possible on the more limited budget of les Jardins de la Grelinette where Jean-Martin and his wife Maude-Hélène Desroches grew food for 200 families on two and a half acres. Since 2015, Maude-Hélène has been the solo operator of la Grelinette (an hour away from FQT).
With good techniques, equipment, and varieties, and enough personal energy, year-round production can provide premium local vegetables and make a profit. This book will inspire and help. It is packed with detailed vegetable profiles, tips for winter crop planning, and successful growing and storage of fall/winter crops. There is precise information on tool selection and best use, and on selecting shelters, from rowcover to high tunnels. The book was written in the authors’ native French and ably translated by Laurie Bennett. I love the word “shelters” to include all kinds of protected growing, and I hope it comes into common use in English!
The Winter Market Gardener builds on years of research, experimentation, and collaboration, as all who have read The Market Gardener will appreciate. It is a practical guide to winter vegetable production for small farmers in northern climates, and elsewhere. Initially I thought this would be a delight to read, but not of much practical use to me in central Virginia, a very different climate. I soon found I was wrong. Questions of the value and profitability of types of greenhouse and tunnel heating are thoroughly considered, in terms of heat sources, financial and planetary costs, and benefits. There is info on some crops I have never grown, not here nor in England. The crop planning calendars have solid info in a nice accessible intuitive format. There are charts, graphs, illustrations to help you get started or smooth your path in winter growing.
Don’t think for a minute that running a farm owned by a multi-millionaire means efficiency and results are unimportant! It does permit some enviable pricey equipment, but careful trials, record-keeping, and profitable products are essential to the purpose of the project.
The concept behind Ferme des Quatre-Temps is to find the sweet spot between intensive organic production, and a biodiverse landscape. Jean-Martin and a team of permaculturists came up with the design for the farm, including the livestock. The theories and practices are taught to a group of apprentices each year, and via the online Market Gardener Institute, and its Masterclass.
Whatever your level of experience or scale of production, The Winter Market Gardener will encourage and inspire you to value high-quality local vegetables all year, and give you tools to produce them in winter. There is an appendix for people wanting to use these methods on a backyard scale. 645 ft2 (60 m2) can grow enough vegetables for 3-5 people for the whole (Québécois!) winter. And, of course, you can grow summer vegetables there when winter is over.
Don’t think growing vegetables all-year means no time off – you just need to plan to include breaks, or rotate workdays around the crew. And remember that winter has shorter days and a slower pace than summer. For those growers pursuing an honest life of hard work on stuff that matters and makes a difference, here is a guidebook.
As the number of winter growers increases, the demand for fresh food increases, and we have job security! To be sustainable, winter harvesting must be profitable, so invest in this book. It may happen that small-scale winter food production becomes not just the tastiest option and least-damaging to the planet, but our only option. During the Covid pandemic, it became plain that in the Northeast of North America, 70% of vegetables come from California, Mexico, or even further afield. It took only three days to deplete the supply of fresh vegetables in the stores.
Some countries responded to this realization by providing grants for local food growing, including high tunnels and greenhouses. Catherine and Jean-Martin propose that giving the money to fifty or 200 small-scale farms would be a better investment than giving it to a twenty-hectare tomato greenhouse, (as happened in Quebec). Production of cold-hardy vegetables in winter uses much less energy than growing tomatoes! Additionally, growing summer vegetables in winter requires artificial lighting, causing light pollution, disrupting the circadian rhythms of humans and other animals. No one yet knows how artificial lighting affects the nutritional quality of food grown that way.
Catherine Sylvestre. Photo New Society Publishers
Jean-Martin and Catherine identify five key principles of winter growing:
Lack of sunlight in winter is more limiting than lack of heat.
Many vegetables can withstand freezing temperatures.
Cold-hardiness in crops can sometimes be bred for.
Layered shelters (rowcover, tunnels) can allow more vegetable production in winter.
Installing minimal heating can make winter growing more successful, and can be profitable.
A useful chart suggests how many layers of rowcover to use at various night temperatures and daylengths. This guideline that could work wherever you grow.
There are good descriptions of making low tunnels and caterpillar tunnels. High tunnels (hoophouses, polytunnels, passive solar greenhouses) are permanently located and usable year-round, although unheated. Greenhouses are permanent structures, heated, somewhat insulated, made of glass or two layers of plastic. There is a small chart showing the outdoor killing temperatures of four crops, unprotected outdoors, in a high tunnel and in a high tunnel with P19 rowcover. For example, lettuce will die at 21°F (-6°C) outdoors with no protection, at 7°F (-14°C) outdoors if protected by a high tunnel, and at 0°F (-18°C) outdoors, if under rowcover in a high tunnel. This is followed by a comparison of the various shelters in terms of cost, thermal gain and features and uses.
Don’t consider adding heating unless you have at least a double layer of plastic and in-ground perimeter insulation. At la Ferme des Quatre-Temps they have perforated polyethylene tubing that distributes hot air along the beds. The increased revenue from faster growing crops must be covered by the increased costs of heating or adding more layers of rowcover. They present a table and a bar chart comparing cost of heating, cost of labor to manage row covers, and revenue. For their situation, heating to 37°F-41°F (3-5°C) trounces no heating, and beats heating to 54°F (12°C). It also matters how much workers are willing to move rowcovers, or enjoy doing that as part of winter growing.
To reduce heating costs, check your insulation. Regularly monitor and repair broken parts of your structure. If you are buying new, remember that bigger structures hold more warmth from the daytime. Ensure your heater is an efficient one, and you have blowers to push the heated air around.
Here’s a counterintuitive bit that makes complete sense once you’ve thought it through: On short cloudy days, there’s little point in adding heat, because the plants won’t be able to photosynthesize more. On warm sunny days, if the temperature is still low, your plants could gain photosynthesis with a higher temperature to balance the good light.
Avoid letting the humidity remain over 90% for more than a few days at a time. Ventilate, and if necessary, heat for an hour while doing that! Be sure to ventilate if the sun is shining. One of my hoophouse mantras this winter is “More air, less water!” – good airflow is vital to keep plants healthy.
As for heating, what fuel to use? Ecology is important, environmental awareness is a guiding value. Profitability has to be in there. Fossil fuels are not sustainable. Electricity produced by coal or nuclear power has no appeal. In Quebec, growers are fortunate to have hydroelectricity, from a publicly owned utility. Even with such a benign fuel source, there is still a decision to be made about the delivery system: a furnace with an electric coil or a heat pump? A short physics primer on electric heating follows. This gem of info can save you from a permanent expensive mistake! For example, surface geothermal might cost $10,000, but regular geothermal could cost $125,000! There’s a thorough table comparing pros and cons of various types of heating, and a full-page color photo of hot air distribution tubes.
The next section is on winter crop planning. To grow healthy winter crops, first grow strong seedlings with good roots, then harden them off carefully to withstand winter. Use a larger cell size than you would in simmer. Seven days before transplanting into the ground, move the seedlings into colder conditions with more outside air. Gradually increase their cold tolerance over the week.
Lack of light is more limiting than low temperatures. Careful timing is needed to get plants to the right size before daylength reduces to ten hours and growing slows right down. The key is to get plants to 70% of their final size before this happens. Further south, the dark period is shorter, the soil holds temperature until later in the year, and you have more wiggle room. In northern climates, greenhouses and tunnels become outdoor storage rooms.
There is a chart of winter days to maturity of tatsoi, spinach and turnips, and days to reach 70% full maturity. Days to maturity increase as daylength decreases. Keep records of winter days to maturity of the crops you grow, calculate 70% of that time and work back from your last day of ten hours of daylight, and find the target date to sow that crop. Keep records of sowing dates and results.
For a continuous supply of cut-and-come-again leaf crops, calculations are more complicated. Keep good notes of when you sow, cut, and can come-again. You might get three cuts, or six, depending on your location. Figure a good sowing date, and don’t delay! You could do some trials with short rows sown on different dates.
The authors provide a table of winter sowing dates for twenty-five crops sown outdoors with P19 rowcover; in a caterpillar tunnel; high tunnel; and minimally-heated greenhouse. Plants can sometimes endure an hour or two at a temperature considerably colder than they can tolerate for several days.
Crop density may need to be decreased to ensure plants get enough light and airflow. Growing plants closer in the row, but with rows further apart (growing about 70% the number of summer plants), provides better light. There’s an appendix on crop spacing.
It is helpful to know when each crop is likely to bolt after the solstice. Some bolt earlier than others. Keep records and harvest accordingly.
The crop profile section follows. There are icons indicating semi-hardy crops (32°F to 25°F/0°C to –4°C), cold-hardy ones (23°F to 14°F/–5°C to –10°C); very cold-hardy crops (14°F to 22°F/ −10°C to –30°C); minimal heating, no heating, overwintering; transplanted, and direct-sown crops. The sidebar also includes recommended varieties, spacing and seeding and transplant dates in Quebec. Each profile has a beautiful full-page watercolor image. The text includes info on first harvest, succession sowing, intercropping strategies, pest and disease challenges, and good harvest practices.
Jean-Martin Fortier with his broadfork.
Next comes the section on recommended tools: broadfork, bed prep rake, (tilther perhaps), wheel hoe, two-wheel tractor (BCS), power harrow, rotary plow, (six-row seeder perhaps), Jang seeder, Earthway seeder, four-row pinpoint seeder (I could become a convert to this handy little tool!), stirrup hoe, collinear hoe, wire weeder, Terrateck wheel hoe with bio-discs, flex-tine weeder (looks good!), harvest knives, quick-cut greens harvester. 2023 prices are in an Appendix. I liked the home-made greens bubbler, a water tank with air bubbled into it, to agitate and clean the leaves.
Next is a section on tending your winter crops. How to have an unfrozen water supply (they don’t need any irrigation in unheated shelters in December or January). Why to avoid over-fertilizing (increased salt buildup, soil diseases, thrips and aphids). How to warm the soil, increase soil microbial activity, and rate of crop growth with landscape fabric, black plastic or rowcover. How to trap mice, and deal with pest insects when it is too cold for beneficial insects.
That section is followed by one about planning fall harvests of storage crops, which combines well with winter harvest of leafy greens, for more sales. Think not only of carrots, turnips and potatoes, but also of beets, cabbages, winter squash, parsnips, rutabagas, kohlrabi, onions, leeks, celeriac. There is. as always, encouragement to keep good records.
I really like their planting charts, where each crop is shown in its special color, occupying a physical amount of space (a column for each bed), and a time (rows for the weeks). With this plan in place, quick late summer crops can be squeezed into some beds, or cover crops. Each outgoing crop is flail-mowed, and covered with a silage tarp for two or three weeks. The soil micro-organisms break down the plant matter under the tarp, leaving the bed ready to replant without tilling. Tarping takes longer than tilling, but the method treats the soil and micro-organisms more holistically.
The general material about fall growing is followed by crop profile pages for suitable storage crops. Their method of transplanting beets gets better germination rates and uniformly filled beds. It gives me the idea of transplanting beets from thickly-emerged areas to gaps in our direct-sown beds, as we do with fall kale. There are helpful tips about carrots following garlic (we do this) because the soil will be relatively weed-free after months of garlic mulch; growing celeriac on landscape fabric, because it is in the bed for so long; storing Napa Chinese cabbage for 3 months in closed bins at high humidity; making sure not to create cracks in kohlrabi for storage; transplanting rutabagas. I’m a big fan of transplanting, but I’m learning about more crops that transplant well.
The authors advocate the same system we use for harvesting crops in the fall: determine the winter-kill temperature for each crop, list them in descending order, and work down the list, monitoring the weather forecast.
There is encouragement to build a well-insulated room with a household air-conditioner reconfigured using the CoolBot device to run at lower temperatures. If possible, make two storage rooms, one at 50°F-59°F (10°C-15°C) and one at 32°F-39°F (0°C-4°C). This is the first time I’ve seen advice to also install a heater, for occasions when outdoor temperatures are just too cold. I think we don’t need that in Virginia, but I believe Northerners do!
There are instructions about humidity, about managing ethylene and CO2, and managing inventory. There is a two-page table of storage conditions, containers, and length of storage for thirteen crops.
The last section of the book is Growing and Selling Vegetables Year-Round. Plan not to stand in the freezing cold all day at market! Options include a CSA; an online store with once-a-week deliveries to a select few locations; restaurant sales with a weekly Fresh List. Being reliable and communicating clearly is key, as is coordinating the orders and making a harvest list for the crew.
The world needs more small-scale year-round growers, supplying local markets. In Quebec in 2020, there were more start-up farms than farms closing down – the first time in fifty years! We do not need vertical farms of hydroponic vegetables, using large amounts of energy, priding themselves, curiously enough, on not using soil to produce food. Or food-like products. The diversity and flavor of four-season vegetables grown in soil can’t be beat.
Preparing to sow Rainbow Chard in 2018. Photo Pam Dawling
Vegetable Seed Varieties for 2024
Have you ordered your seeds for next year yet? The earlier you order, the best chance you have of getting the varieties you want. Later, some will sell out. It’s true that when you order very early, some seeds won’t be available yet. The seed growers are still drying and cleaning them, weighing them and running them through germination testing. Your patience will be rewarded with high quality seeds.
I love looking through catalogs to find new exciting-sounding varieties! After so many years of gardening, I’ve tried lots of different kinds, and have definitely grown attached to some reliable favorites. I recommend planting a small amount of a variety new to you that sounds good, alongside your usual well-loved variety. And what do I mean by “sounds good”?
In 2014 I wrote Reading Between the Lines in the Seed Catalogsto share what I’d learned about decoding catalog-speak, and not getting distracted by wondrous claims, failing to notice the catalog never even claimed it had good flavor. Or high yields. Or good disease-resistance. That post lists 15 features to look for.
We look for flavor, productivity, disease-resistance, an appropriate fit with our climate or latitude, general adaptability, varieties that don’t require erecting elaborate trellises, ones that don’t sprawl too widely, ones that don’t take a really long time to reach maturity.
If we’ve had a few years of poor performance from a crop, we’ll try several new varieties. We have done trials of heat-tolerant eggplants,winter spinachfor the hoophouse and outdoors, storage cabbage, and now we need to start over with broccoli.
Green Magic broccoli Credit Johnnys Seeds
For many years we grew three varieties of hybrid broccoli with different number of days to maturity. That enabled us to sow them all on the same day, transplant them all on the same day (or in the same week), and get an extended harvest period. Some of our favorites dropped out of the market, we floundered with various kinds, including some Open Pollinated varieties that sounded good. This year I am advocating for Green Magic (57d F1, 6-8″ main head and sideshoots too); Belstar(65d F1, also 6-8″ main head, plus sideshoots); and Marathon (68d F1) or Fiesta (70d F1, 6-7″ head, few sideshoots, short harvest window). Marathon has done well for us in the past. In my experience, broccoli is a crop where hybrids are much more productive than OP types.
Green Machine zucchini. Photo Johnny’s Selected Seeds
Our much-loved Tendergrey zucchini, one of the flecked pale green types, isn’t easily available this year. But Green Machine (45d F1) sounds very good! Open plant habit is a phrase I like. Moderate spines is one I don’t like, but we have some pull-on plastic sleevesto deal with irritating plants. Widely adapted, excellent disease package, and high yields all appeal to me.
We rely on Provider(50d OP) and Bush Blue Lakesnap beans every year, with a short row of Strike in the hoophouse a month earlier than outdoors. We found we need an upright variety to get nice beans undercover, as the bean plants grow sprawlier than they do outside, and we don’t want to be treading on them.
Washing Cylindra beets for storage. Photo Wren Vile
We rely on Cylindra or Formanova (54d OP) beets, long-shaped tender ones that grow up out of the ground, are tender and easy to peel after cooking. Seems like the yield must be high when half the root is above ground, and half below!
Premium Late Dutchcabbage (100d OP) has done well for us. Johnny’s has a lovely-sounding storage cabbage, Promise(96d F1). 6 ½ lbs at 18″ spacing, 9-10 lbs at 24″ spacing. And two attractive purplish Chinese cabbages Red Trumpet (60d F1), a tall Michihili type, and Merlot (60d F1), said to be an improved Red Dragon Napa type. I hadn’t got round to trying Red Dragon yet, so I can’t speak to its shortcomings. Merlot admits to being more prone to tipburn than green varieties and to be somewhat susceptible to bolting. Some trials on a small-scale are called for!
Merlot purple Chinese cabbage. Photo Johnny’s Selected Seeds
Carrots – oh why so many yellow, purple, red and black ones? None in my experience match the succulence and growth rate of orange Danvers 126.
Collards – for years I have loved Morris Heading, but the recent explosion of options brought us by the Heirloom Collard Project is leading us to try others. Some have remarkable colors, combined with high yields.
The delicious early Bodacioussweet corn is harder to find. Thanks Southern Exposure for carrying it. Our reliable favorite Kandy Kornhas become hard to find.
Our favorite slicing cucumber has been renamed by Fedco as Generally, a name we’ve been using for years. This year we also tried South Wind from Common Wealth Seed Growers and were quite taken with its sweetness.
South Wind slicing cucumber. Photo Common Wealth Seed Growers
As always, there are new frilly mustards for baby greens and salad mixes. We like Mizuna, Golden Frills, Scarlet Frills and especially Ruby Streaks. I feel drawn towards purple stemmed Ember and dark red Miz America.
For leeks, we grow King Richard and Lincoln for fall and Tadorna for overwintering in our Zone 7a climate. No complaints there. all are very good for their purpose.
I’m always on the lookout for new lettuces. This summer we tried Albachiara from High Mowing, and it did very well. We’ll get more for this coming year. It’s a Batavian heat-tolerant type. Now our climate is changing, we need to grow Batavians for more weeks of heat. Finding a new one is great! Dark red Cherokee has been my favorite.
I shouldn’t even look at the spring lettuce selection, or I’ll order more than we can use in the short spring season we have. Most spring varieties can be grown in the fall here too, but we like to switch to cold-tolerant ones.
Ezrilla, a favourite cold-hardy lettuce. Photo Wren Vile
For scallions we like Evergreen Hardy White (65d OP) every time, and feel no need to try another.
We have been growing Sugar Ann early dwarf snap peas in our hoophouse (sown Feb 1), but next year we are trying Oregon Giant snow peas instead. We think snap peas are best raw, and used to cut them into our salad mixes. But over the past few years, by the time the snap peas are ready to harvest, our winter salad mix days are coming to a close, and our outdoor lettuce head harvest is starting. We don’t grow enough snap peas to serve them on their own in big bowlfuls. We think we’ll be able to pick enough snow peas for stirfry mixes instead! In March we sow Sugar Ann outdoors and get plenty.
For sweet peppers our keywords are prolific, thick-walled, tasty, and 90 days or less from transplant to ripe harvest (76d to green). We like fairly large peppers too, and avoid small pointy ones that could get confused with hot peppers in the fridge.
Tomatoes are a whole topic on their own. We love Sun Gold and Black Cherry, Mountain Magic and Garden Peach. Others come and go. Next year we are trying Damsel (73d F1). Damsel is in the new tomato category called “Hylooms” – hybrids resembling heirlooms in color and flavor, with added disease resistance.
Damsel (71d F1) Hyloom tomato. Photo High Mowing Seeds
Our winter squash storage cage. Photo Twin Oaks Community
Key factors to consider when selecting vegetables for long-term storage
Most storable vegetables are roots or tubers.
Winter squash, onions and garlic are the main exceptions.
And tree fruits such as apples and pears.
There are hard-headed storage cabbages too, but those varieties are getting harder to find, as fewer people grow for storage. Search the seed catalogs for the word “storage”. Other varieties are for fresh market, or processing, and won’t store for long.
Don’t plan to grow a specific crop unless you have the right kind of place to store it!
You also need a likely market. I love celeriac, but it’s not widely known, so I wouldn’t recommend growing lots until you have an idea of the demand.
Choose varieties that are sturdy and chunky, not slender carrots, for instance. (Shriveling is related to the ratio of volume to surface area.)
Ideally, practice that variety on a small scale the year before growing a very large amount, to see how it does in your soil.
If it’s too late to do that, try three different varieties and keep records of how they do.
Read the small print in the seed catalogs! Moschata winter squashes such as butternuts. Long Island Cheese and Seminole store all winter, but acorn squash do not. You can store acorn squash for a couple of months, but then move them along to people’s dinner plates.
Harvesting tips to maximize the storage life of stored vegetables
Carrot harvest cart Photo Mari Korsbrekke
Storing vegetables is very much a Garbage In-Garbage Out type of thing. If you put unsound vegetables into storage, they will rot and the rot could spread.
Good storability starts with good growing techniques
During growth, fend off any serious pest predation, as crops with holes in may not store well.
Be sure you know the temperature at which each crop will suffer cold damage, and get it harvested before that happens.
Harvest when the crops are optimum size and in peak condition.
Ideally, harvest in dry weather.
Handle the vegetables gently. Bruises can happen invisibly, so if you drop something, don’t store it.
White potatoes can reach a storable state two weeks after the tops die in the field. If you are in a hurry, mow the tops off, then wait two weeks. Check that the skins are “set” and don’t tear, if you rub the potato with your thumb.
Sweet potato harvest crates Photo Nina Gentle
Trim leafy tops from root vegetables, leaving very short stems on beets and carrots. During long storage, the stubs of the leaf stems may die and drop off, but this is nothing to worry about.
If you cut the tops off beets completely, the red color will wash out during cooking. Definitely don’t cut into the root part of beets when trimming. Some people trim the long ends of beet roots, but I never have. They don’t take up much space!
I do trim the roots from kohrabi, and for that task, I do cut into the bulbous part of the root, as the skinny root has such a high concentration of fibers that it’s like a steel cable! The cut surface soon heals over.
Look each vegetable over and only store ones without soft spots or deep holes. Carrots or sweet potatoes snapped in half can heal over and store just fine, but stabbed potatoes won’t. Superficial bug bites will heal over but not tunneling.
Small roots won’t store well. We have a “training tool” for new crew members which is a bucket lid with holes cut in it. If the carrot can pass through the carrot hole, it’s too thin to store well. Potatoes less than about an inch are not worth storing. Likewise tiny turnips.
Bucket lid with holes for sorting root vegetables for storage. Photo Wren Vile
For traditional storage without refrigeration, most roots store best unwashed (less wrinkling). This can make them harder to clean later.
If you are going to store root crops unwashed, consider setting them in a single layer on the field and making a second trip round to pick them up into crates when the skins are dry. If you are going to wash them, the opposite is true! Get them into water before the skins dry, to help the washing go quicker. We don’t wash sweet potatoes, white potatoes or squash. We do wash all the other root crops, as it’s harder to get them really clean if the soil dries on them. Provided you store them in humid enough conditions, they will not shrivel.
Some crops need curing before storing (alliums, peanuts, sweet potatoes, white potatoes).
Tops of garlic and onions can be trimmed after the crops have cured and the leaves died. Making braids or ropes of alliums with their tops on can be a profitable option.
The best storage conditions for different types of vegetables
Crates of potatoes in our root cellar. Photo Nina Gentle
In my book, Sustainable Market Farming, I have a whole chapter on Winter Vegetable Storage.
Growers have only good things to say about the CoolBot system from Store-It-Cold. Basically you build a well-insulated space (shed, room, truck body), buy a window AC unit and the CoolBot and follow their excellent instructions to install the device which lets you run the AC at a lower temperature, like a refrigerator, at a fraction of the cost.
Hang a thermometer in your storage spaces, so you know when to warm or cool them. Digital thermometers might measure humidity too.
You can get a small electronic device that will send an alert to your phone if the temperature goes too far out of range.
For storing white potatoes without refrigerators, the best place is a root cellar. You are aiming for cool and moist conditions: 40-50°F (5-10°C), with 85-90% humidity. You really don’t want to store potatoes below that range, or they go black when you make fries.
Most other vegetables fit into four other sets of storage conditions:
A. Cold and Moist (33-40°F/1-4°C, 95-100% humidity, works for most root crops, and also cabbage, Chinese cabbage, kohlrabi and leeks.
B. Cool and Moist is mostly potatoes, as I already mentioned. Pears, apples and cabbage also store well in these conditions but not sharing space with potatoes! More on that later.
C. Cool and Dry is for garlic and onions. 32-40°F/0-4°C and 60-70% humidity. It’s also possible to store alliums warm and dry at first, 65-85°F/18-30°C, but definitely not 40-56°F (4-13°C) for garlic, or 45-55°F (7-13°C) for bulb onions or they will sprout. Never warm after cold either.
D. Warm and Dry to Fairly Moist is for winter squash and sweet potatoes. Never below 50°F (10°C). Ideal temperature 55-59°F (13-15°C). Temperatures above 65°F (18°C) hasten sprouting. Also ripening green tomatoes like 55-70F/13-21C and moist (75-85%).
For the warmer options, barns or basements might be suitable in the fall, before they get too cold.
If you are planning a new barn, consider installing an insulated basement to be a root cellar.
There are traditional in-ground storage methods, such as clamps, pits and trenches. The easiest version of this, in the right climate, is to mulch heavily with about 12″ (30 cm) of insulation (such as straw, dry leaves, chopped corn stalks, or wood shavings) over the row, and maybe add low tunnels over the mulch.
In-ground vegetable storage Drawing from WSU
Clamps are made by setting down a layer of insulation on the ground, piling up the crops in a rounded cone or ridge shape, covering thickly with straw, then working round the mound digging a ditch and slapping the soil up on the mound.
Vegetable storage clamp. Drawing from WSU
Pits and trenches start by digging a hole, lining it with straw or an old chest freezer, layering in the vegetables with straw and covering with boards and a thick layer of insulation. Insulated boxes stored in unheated areas need 6-8″ (15-20 cm) of insulation on the bottom, sides, and top.
This all takes a lot of work, so look into the CoolBot idea first!
Suitable containers for storing vegetables
We use perforated clear plastic sacks for roots, cabbages and kohlrabi. They reduce the water losses that lead to wrinkling.;
We use net bags for onions and garlic; plastic milk crates for potatoes;
We use folding plastic crates for squash and sweet potatoes.
We leave horseradish, Jerusalem artichokes and leeks in the ground here in zone 7a, but we don’t get frozen soil for much of the winter.
We don’t use any packaging materials, but in England in the past I stored roots in boxes of damp peat moss, sawdust, sand or wood ash. I find it better to get the right storage conditions for the vegetables, rather than try to insulate them in their crates.
Set the containers on pallets, not directly on concrete floors, to reduce condensation.
When stacking your containers, allow gaps along the walls and between stacks, for airflow. Celeriac needs more ventilation than beets or kohlrabi, for instance.
Sometimes night ventilation offers cooler drier air than you can get in the daytime.
Vegetables that have particular needs for long-term storage
Sweet Potatoes in storage. Photo Pam Dawling
Sweet potatoes must be cured before storage. This means hot humid conditions until the skins don’t rub off when you rub two together. After that you can move them to storage conditions (or turn down the heater and humidifier!)
It is important that sweet potatoes never go below 50°F (10°C) or they will suffer a permanent chilling injury that makes them almost impossible to cook. I know because I’ve made that mistake, leaving them in the ground too long, hoping they’d grow bigger.
White potatoes also need to cure until the skins toughen, in moist air (90% humidity) for 1-2 weeks at 60-75°F (15-24°C). Wounds in the skin will not heal below 50°F (10°C).
We sort our potatoes after two weeks of curing and find that sorting at this point usually reduces the chance of rot so that we don’t need to sort again.
They need to stay moist so they don’t wrinkle. They have fairly exacting temperature requirements so they don’t sprout.
Remember to keep white potatoes in the dark while curing as well as during storage.
Home vegetable storage options, from WSU
Some vegetables exude ethylene in storage: fruits, damaged produce, sprouting vegetables. Some crops are not much affected by ethylene (greens for example) and can be stored in the same space with ripening tomatoes, for instance.
Other vegetables are very sensitive to ethylene, and will deteriorate in a high-ethylene environment. Potatoes will sprout, ripe fruits will go over the top, carrots lose their sweetness and become bitter.
When storing ripe fruit, ventilate with fresh air frequently, maybe even daily, to reduce the rate of over-ripening and rotting.
Ethylene also hastens the opening of flower buds and the senescence of open flowers.
Alliums like it drier than most crops. Heed my warning about the “danger zone” sprouting temperatures. Not 40-56°F (4-13°C) for garlic, or 45-55°F (7-13°C) for bulb onions or they will sprout.
Tips for extending the storage life of vegetables
For non-refrigerated storage, unless using outdoor pits or clamps, several smaller containers of each crop are often a safer bet than one giant one, in case rot sets in.
For crops that store best at 32°F (0°C), if you can only store them in warmer temperatures (up to 50°F/10°C), provided they do have high humidity, you can expect to get about half the storage life they’d last for in ideal conditions.
After you’ve put your produce into storage, don’t completely forget about it! Keep a record of what is stored where and perhaps a check sheet for inspection. Monitor the rate of use and notice if you’d benefit from more or less of each crop next winter.
Regularly check the storage conditions are still meeting your goal, and check thorough the crops at least once a month, removing the bad ones. Shallow crates make this easier.
For root crops and squash, and maybe alliums, the initial storage period is the most likely to show up trouble. Later the crops become more dormant and less change happens.
Keeping root cellar temperatures within a narrow range takes human intervention, or sophisticated thermostats and vents.
If needed, electric fans can be used to force air through a building.
Make a realistic assessment of how long your crop will last in the actual conditions you are providing, and plan to move them all on before then.
You may be able to reallocate crops to some colder spaces as some of the original produce stored there gets used.
After long storage, some vegetables look less than delicious, and benefit from a bit of attention before the diners get them. Cabbages can have the outer leaves removed, and can then be greened up by exposing to light for a week at 50°F (10°C). This isn’t just cosmetic – the vitamin C content increases ten-fold. Carrots can lose their sweetness over time, unless frequently exposed to fresh air, by ventilating well.
Storage #4 green cabbage. The name says it all. Fedco Seeds
Our hoophouse beds after the nights at 2F (-17C) and 8F (-13C). Looking amazing! Pam Dawling
We were luckier with the weather than many people over the weekend (12/23-12/26/2022). And so were our vegetable crops. On Friday 12/23 we prepared for a suddenly very cold night. It was very windy as we battled to stop the hoophouse windows from blowing open. We finally got some shims, a hammer and a stepladder, and wedged them closed. They stayed that way until Tuesday 12/27. We were fortunate in getting no precipitation (I hate ice!) and no power outage.
Pool noodles repurposed as draft excluders. Pam Dawling
We fortified the doors with our rock collecting buckets, and prevented most of the under-door drafts with our pool noodle draft excluders. They have a rope running through them, which is hooked onto small cup-hooks on the door frame. We repurposed noodles that had been used as props at a party or some other kind of event. They had been covered in tube socks and had glued-on googly eyes.
Rolls of rowcover at the ready in our hoophouse. Pam Dawling
It was a bit unnerving being in the hoophouse as it creaked and groaned in the wind. In the winter we keep rolls of rowcover ready for any night we think will be below 8F (-13C). We unrolled the rowcovers by lunchtime and laid tools on the ends nearest the doors. I was worried that if we lost power, and therefore the inflation, it would get very cold indeed in the hoophouse.
The DIY manometer in our hoophouse. (the background lines have faded). Pam Dawling
Since we last changed the plastic we haven’t managed to get the recommended 1/3” (8.5mm) pressure difference in the “bubble” between the plastic layers, compared to our normal air pressure. Mostly we don’t even get ¼” (6.5mm). The “bubble” provides thermal insulation as well as physical strength against snow or ice buildup, and strong winds.
It got down to 2F (-17C) outdoors Friday night, and Saturday didn’t warm up much. I don’t actually know what the night temperature was in the hoophouse as our recorded low temperatures don’t make sense: 14F (-10C) for four consecutive nights (Fri to Mon). I suspect we didn’t reset the thermometer correctly. Usually the hoophouse can hold 8 F (4.5 C) degrees warmer than outdoors, but not 12 F (7 C). It looks like it did, perhaps because we didn’t open it all day!
Soil thermometer in our hoophouse on 27 December 2022. Pam Dawling
The soil is still nice and warm in there: 59F (15C). That really helps. The rowcovers are usually removed in the daytime, either pulled aside if we expect to need them again the next night, or rolled up out of the way. Most of the time they stay rolled up at the east end of the hoophouse. We appreciate not needing to deal with rowcovers most of the time! On Saturday 24th, the temperature maximum for the day outdoors was 24F (-4.5C), and we kept the rowcovers in place over the crops. On Sunday the high outdoors was 28F (-2C) so we pulled the rowcovers aside until the night. On Monday 26th the night-time forecast was benign enough that we rolled the rowcovers up. And now we get a milder spell.
Hakurei turnips with frozen yellow leaves where they touched the plastic (rowcover protected the plants). Pam Dawling
How did the crops fare? It’s not always obvious at first if a crop has been killed by cold or not, But I can now say with confidence that nothing died. The edge beds are always the coldest. The south edge bed had Hakurei turnips, delicious and notoriously the least cold-hardy turnip variety. Most of the globe of the turnip sits on the surface of the soil. You can see in the photo that some of the leaves, the ones right by the wall plastic, have been killed and turned yellow. But the roots themselves (with rowcover over them) seem fine.
Bright Lights chard with cold-damaged stems in our hoophouse north edge bed after nights at 2F and 8F Pam Dawling
Over the other side, in the north bed, we have some Bright Lights chard, among other things. Multi-colored chards are less cold-hardy than red ones, which in turn are less cold-hardy than green ones. We know we take a risk in growing Bright Lights through the winter, but we so enjoy the sight of the short pieces of colored stems in our salad mixes that we take the risk. Some of the stems have curled over, probably on their way to dying, but the plants live on, to provide many more salads this winter! And some cooked greens too.
Some of the giant senposai leaves, where not fully protected by the relatively narrow rowcover, have developed tan dead spots, so those leaves can just continue as the plants’ solar panels until we get tired of looking at them and decide they are no longer needed.
Each winter I update my Winter-Kill Temperatures of Cold-Hardy Vegetables list, except this past spring I had nothing new to add. Outdoors, I noticed today that the tatsoi has definitely died, the Vates kale and the spinach have survived (uncovered) and the small garlic leaves don’t seem troubled. The leftover lettuce transplants have been damaged, if not killed.
