What makes vegetable crops bolt and how can I stop it?

Hoophouse spinach in May. Back: bolting Renegade; Front: Escalade.
Photo Pam Dawling

What causes bolting?

 

This is an updated version of the section I included last week, followed by the all-important section on how to stop  or at least delay, plants from bolting.

Bolting is the term for plants going to seed. Rather than grow more leaves and bigger roots, the plants develop stems, fewer and skinnier leaves, then flowers and seeds. The plants are switching their energy to survival of the species in response to the conditions.

When a plant starts to bolt, it is usually a sign to expect a poor harvest. It is also an indication that the plant will decline in terms of flavor. Lettuces become bitter. As long as you can harvest leaves or roots that are not too woody, you can eat bolting plants. But they do become too tough and inedible at some point.

Although bolting is usually seen on crops approaching maturity, it is initiated much earlier, by plant hormones called gibberellins. Bolting then can be triggered by one or more factors, sometimes acting in concert.

  •  ·         Increased day length: Bolting can happen (especially with annual crops) when day length increases as summer approaches. This can be a problem if you planted your seeds too late in the spring to get a harvest before the plants bolt.
  • ·         High soil temperatures: As soil temperatures increase in summer, annual plants are triggered to begin seed and flower production. This isn’t a problem late in the crop’s life, after bountiful harvests. But, when spring has unusually hot weather or if you plant crops too late into the growing season, your crop may bolt before any harvests. Cool weather crops like lettuce and spinach will bolt in spells of hot dry weather.
Bolting lettuce in July
Photo Alexis Yamashita
  • ·         Cold temperatures: A sudden cold snap in spring can signal to biennials (such as onions, leeks, beets and carrots) that “winter” has happened and it’s time to develop seeds for the next season. If you start these crops too early in the calendar year, you risk exposing young plants to cold weather, priming the plants to develop flower stems as soon as the weather warms up again. 
  • ·         Plant size: larger plants are more likely than small ones to bolt when a trigger such as cold temperatures strikes.
  • ·         Annual plants (basil, lettuce, melons, peas) grow from seed, flower and set seed all in one year. That can be spring to winter or fall to summer. Annual crops are sensitive to daylength, and will start making flowers as the daylength (and temperature) increase. Many annuals are crops where we eat the fruit or seeds and bolting is not an issue.
Bolting Vates kale at the end of March
Photo Pam Dawling
  • ·         Biennial plants (beets, brassicas (broccoli, cabbage, kale, turnips etc), carrots, celery, chard, leeks, onions, spinach) grow big the first year, then seed the second year, if we still have them. Many biennial food crops are grown as cool weather annuals. Unsettled weather (cold nights, hot days, late frosts) early in the season can cause biennials to bolt. Bolting usually occurs after a prolonged cold spell, especially with immature plants. Brassicas started in cool conditions, and grown on in warmer conditions, are primed to bolt. Tatsoi, for example, bolts readily in these conditions.
Tatsoi preparing to bolt – note the smaller leaves and developing flower buds
Photo Pam Dawling
  • ·         Root stress: Bolting caused by root stress typically happens when you disturb a plant’s root system by transplanting, or if your plant runs out of growing space in a container that’s too small, or because the rows did not get sufficiently thinned.
  • ·         Stresses such as insufficient minerals or water: Healthy soil with plenty of nutrients and balanced moisture levels will encourage quick growth. Every grower should aim for this balance, especially those in hotter climates where it’s a race to plant leafy salads, cooking greens and root crops before the hot weather wins. High salt levels are another stressor, particularly in hoophouses.
Bolting Russian kale in our hoophouse March 28
Photo Pam Dawling

Avoiding or postponing bolting

  •  ·         Investigate, record and follow local last planting dates for early spring crops, and first planting dates for fall crops.
  • ·         For some crops there are varieties that are resistant to bolting, such as ‘Boltardy’ beets. If you have had repeated trouble with a particular crop bolting, look for bolt-resistant varieties. Florence fennel is particularly prone to bolting so try ‘Amigo’, ‘Victorio’ and ‘Pronto’ varieties and sow in summer for fall harvests. White and brown onions are less prone to bolting than red varieties.
  • ·         Onions grown from sets (plants stymied in mid-growth) are prone to bolting. Grow onions from seed or plant heat-treated sets in early spring (exposure to high temperatures suppresses flower-bud formation)
  • ·         Try to avoid stressing your plants.
  • ·         Direct sow. Plants prone to bolting due to root stress (beets, carrots, radishes, turnips, and many herbs) grow best when you direct sow them, rather than transplanting. This allows their root systems to develop without interruption.
  • ·         Transfer seedlings to a larger pot before the roots get crowded (“root bound”)
  • ·         Harden off plants before transplanting. Get them used to outdoor conditions, avoiding shock.
  • ·         Cover plants in the event of a cold spell, which can keep them from being directly exposed to cold temperatures, rain, or snow.
  • ·         Use seaweed or kelp liquid fertilizer, which help plants handle stress better.
Bolting mustard greens on May 3.
Photo Pam Dawling
  • ·         To postpone bolting in spring, avoid chilling young brassica plants (above 5-8 true leaves, or with a stem diameter above a certain size), below 40°F for a few days, or longer at 50°F (10°C). The interaction of plant size (age) and cold temperatures makes the plant flower. Older plants are more likely to bolt than young plants at the same cold temperature. Young hardened-off plants are very resistant to bolting. If broccoli and cauliflower plants are stressed into flowering while young, the small plants will only produce small heads.
  • ·         Coax your vegetables to maturity quickly and efficiently so they’re ready to eat before the plants have a chance to flower.
  • ·         Mulch spring crops early to help keep the soil and roots cooler, extending the harvest. We have found this to be especially helpful with spring cabbage and broccoli.
  • ·         Cover near-mature bulbing onions during cold spells to protect them from bolting.
  • ·         Use shadecloth to keep greens and lettuce cool as the season warms, or plant them in the shade of other plants
  • ·         Consider the timing of sowing. Grow storage carrots and beets in the fall, not the spring.
  • ·         Many cool-season crops mature better before temperatures get to 80°F (27°C), so plan accordingly. If your springs usually heat up fast as ours do, start earlier, or plant in late summer, fall, or even winter, depending on your climate, and grow these crops in reliably cool weather.
  • ·         Plant later annuals after the summer solstice to grow in the decreasing daylength without risk of bolting (unless another factor such as stress or temperature comes into play).
  • ·         Once cold-hardy plants are big, they can endure cold winter temperatures. They will not bolt until the day length is lengthening again (after the Winter Solstice) and the temperature starts to rise.
  • ·         Brassica greens started in hot conditions do not usually bolt if they have enough water. I recommend both Tokyo bekana and Maruba Santoh (both “celery cabbage” types of Asian greens), for summer substitutes for lettuce. You do have to grow them fast, with plenty of water, and insect netting if you have brassica leaf pests.
  • ·         In central Virginia for outdoors in spring, the only Asian green we grow is senposai, which we have found to withstand bolting until a bit later than others. There may be other loose-leaf Asian greens we could grow, but spring can go from too cold to too hot very quickly here.
Bolting senposai on May 3
Photo Pam Dawling
  • ·         To prevent bolting in Asian greens, sow these crops from July onwards. Asian greens bolt as nights become warmer  on average above 50-55°F (10-13°C)
  • ·         Winter radishes will only form a good root if they are planted in late summer or fall as the days get shorter.
  • ·         Sow quick-maturing plants like lettuce, cilantro, or radish regularly. Succession sowing can keep some plants always coming into maturity instead of relying on one sowing to last a long time without bolting in the garden. 
  • ·         If you grow biennial plants and harvest them in the first year, they are unlikely to bolt. A few specimens may still do so. Chard is cold-sensitive, and by delaying sowing until April, we can  grow chard all summer as a fresh cooking green, and it will not bolt no matter how hot it gets. We cannot keep kale and collards producing all summer as gardeners in cooler climates do.
  • ·         For early harvests of biennials, start the plants in plug flats or soil blocks indoors, planting them out when the weather is more settled and avoiding cold stress.
  • ·         Dry soil can also encourage bolting, particularly with cabbages, cauliflower, arugula and spinach. To avoid this, provide ample water.
  • ·         If the compost is not nutritious enough, top-dress with more compost.
  • ·         For over-wintered leeks and onions, bolting can be delayed by topdressing with 2-3oz per sq yd (70-100g per sq m) of nitrogen rich fertilizer very early in the new year
  • ·         Pick off the outer leaves from leafy crops such as lettuce, keeping the plants from maturing. As well as providing you with multiple harvests, this can extend the harvest period by as much as 10 weeks, although in hot weather the flavor may still become bitter, even without bolting. Grow Batavian varieties in hot weather.
  • ·         With some crops, like basil, if you catch a plant in the very early stages of bolting, you can temporarily reverse the process by snipping off the flowers and flower buds. The plant will go back to producing leaves and will stop bolting. In most plants (such as broccoli and lettuce) this only buys you a little extra time to harvest the crop.
  • ·         Cabbage wrangling: If a cabbage is mature and preparing to split open (a stage of bolting) before you are ready to harvest, you can get a firm hold on the head and give it a quarter turn. This will break some of the feeder roots and reduce the water uptake, delaying splitting.
Bolting over-wintered mizuna, Scarlet Frills and Golden Frills in March in our hoophouse.
Photo Pam Dawling

 Some specific examples

Lettuce is one of the vegetables most frequently seen bolting. I’ve even seen photos of bolting lettuce in garden magazines, with no acknowledgement that the plants are only fit for the compost heap.

The bitter taste of bolting lettuce is caused by a rapid buildup of compounds called ‘sesquiterpene lactones’. Plants manufacture these compounds to provide resistance to leaf-eating insect pests. The plants also speed up their production of seeds to grow the next generation.

Onions (excerpted from Sustainable Market Farming)

Onions are a biennial plant. When onion plants experience an extended period of cooling temperatures, such as winter, they go dormant. When temperatures rise, they start growing again. After being exposed to cold temperatures, smaller seedlings with a diameter less than pencil thickness (3/8” or 1 cm), and fewer than six leaves will resume growth and not usually bolt. Over-large transplants are more likely to bolt. If seedlings are becoming thicker than a pencil before you can set them out, undercut 2″ (5 cm) below the surface to reduce the growth rate.

The trigger for the transition from bulbing to flowering is temperatures below 50°F (10°C) for 3-4 weeks, after the plants have six leaves or more. This can happen, if you are unlucky, after an unexpected cold period in spring. Avoid bolting because the bulbs start to disappear to feed the growing flower stems. Bolted onions will not dry down to have tight necks and so will not store.

It is possible in our climate (and perhaps yours) to sow onions in the fall and plant the seedlings out in the early spring, for bigger vegetative growth and therefore the chance of bigger bulbs. The temperature-and-size trigger limits how early in the fall seeds can be sown – if the seedlings have made lower stems larger than a pencil in diameter when winter closes in, the plants are likely to bloom in the spring rather than forming bulbs. A few onion plants will likely always bolt, especially if the spring is long with alternating warm and cool spells.

Starting seedlings in a hoophouse in early November works well for us. Previously we sowed outdoors in late September and protected the plants with row cover and cold frames, a system that would work fine somewhere warmer than zone 7. The hoophouse works well for us because the plants get much better air flow, are protected from very cold temperatures, and can be easily seen and cared for. The plants grow faster in the hoophouse than outdoors, so we must start them later. Outdoor sowings tend to suffer some winter killing and varying degrees of mold. The colder the temperatures the plants experience, the more likely it is for the larger ones to bolt before growing large bulbs. Hence a more moderate microclimate, such as a hoophouse, reduces the rate of bolting. In colder zones, a slightly heated greenhouse might work better for over-wintering.

A bed of spinach on May 9 – note how the leaves are pointy – the spinach is preparing to bolt.
Photo Pam Dawling

Spinach grows best in temperatures from 35-75°F (1-23°C). Spinach will begin to flower once spring days are longer than 14 hours and temperatures get above 75°F (23°C). The leaves become pointed (arrowhead shape), less fleshy, and the plants get taller, and develop a flower head in warmer weather. Plant spinach 4-6 weeks before the average date of the last frost in your region. You can also sow 6-8 weeks before the first fall frost. You can also plant seed in a cold frame in fall or cover late season plants with rowcover, for harvests during the winter or the following early spring. In warm weather grow chard or leaf beet instead of spinach.

Change your attitude

You can’t control the climate, the weather or the daylength. If you’ve taken the steps listed above and your plants are still bolting, change your attitude!

As soon as you see signs of your greens bolting, harvest the entire plant. According to some excellent cooks, flowering bok choy stems are tender and sweet and make a great addition to stir-fry and salads.

Learn to appreciate peppery arugula or slightly bitter lettuce (mixed in with other salad greens).  It can be more enjoyable than the bland tasting lettuce available in stores.

Bolted vegetables are food for pollinating insects such as bees. Enjoy the beauty of sprays of yellow brassica flowers, majestic globes of leeks and onions, and lacy carrot umbels.

 

Cuba Agroecology: Patio Pelegrin organoponico in Pinar del Rio, Cuba

Patio Pelegrin organoponico garden beds.
Photo Pam Dawling

Visit to Pelegrin Courtyard (Patio Pelegrin) artist family Community Agricultural Project (organoponico) in Pinar del Rio, close to Viñales, Cuba

Day 6 – Sunday January 12 (journey back to Havana)

This is the continuing story of my Agroecology Tour of Cuba with Organic Growers School in January 2020. Search the Cuban Agriculture Category for more posts about other farms we visited.

Our air-conditioned bus left at 8.30 am to visit Pelegrin Courtyard (Patio Pelegrin) artist family Community Agricultural Project (organoponico).

Pelegrin Patio artist community dolls, Cuba.
Photo Pam Dawling

We were greeted by a group of children singing and performing a short sketch. Then we were given a tour, including a caged crocodile, guinea pigs (food?) a catfish pond (catfish are invasive aliens, which Cubans are trying to eliminate by eating them. [I wonder why they don’t feed them to tourists?]

Pelegrin Courtyard pond with turtles and catfish.
Photo Pam Dawling

We saw their vegetables in beds edged with roof tiles. We saw field crops including sweet potatoes and coffee.

Pelegrin Courtyard sweet potatoes (bonato).
Photo Pam Dawling

Again I saw cilantro and creole spinach. I’m still seeking other names for creole spinach.

Creole Spinach at Pelegrin Courtyard, Cuba. The blue fabric is for organic pest control.
Photo Pam Dawling
Close up of creole spinach in Cuba.
Photo Pam Dawling

Creole Spinach is different from Egyptian spinach (Corchorus olitorius), Lalo, Molokheya, Saluyot, Ewedu, West African Sorrel, Krin Krin, Etinyung, Jute leaves. Also see more about Jute Leaves at this link. Note pointed leaves.

Jute leaves. iStock photo

It is none of these tropical “spinaches” either:

Read about those in the Love of Dirt blog by Nicki McKay. Before you click to buy seeds, know that she is in Australia.

Click here to read what Tom Carey has to say about some of these:

  • Nor is it Callaloo (amaranthus spp), bayam, Chinese spinach.
  •           Nor Okinawa spinach (Gynura crepioides, Hong Tsoi, Longevity Spinach);
  •           Nor Malabar spinach (Basella alba, Basella rubra),
  •           Nor water spinach (Ipomoea aquatica), Kangkong). Watch out, that can be invasive.
  •       Maybe Suriname spinach (Talinum fruticosum, (Talinum triangulareTalinum Spinach, Philippine spinach, Waterleaf, Ceylon spinach, Surinam purslane, Florida spinach)? Florida is geographically very close to Cuba. Similar pink flowers.
Talinum Spinach
(Talinum triangulare).
Photo Grow a Gardener Inc, Vegetable Gardening in SW Florida

Learning about these hot weather greens may be useful as our summers get hotter.

I have a bit more information about the Cuban oregano, Plectranthus amboinicus, I saw at several farms, including Alamar Urban Organic Farm . Cuban oregano is a member of the mint or deadnettle family. It has characteristic thick, fuzzy leaves with a strong pleasant odor. The flavor of Cuban oregano is said to be much stronger than Greek oregano.

Pelegrin Courtyard meprobromato treats anxiety.
Photo Pam Dawling

I also saw meprobromato, a herb drunk as a tea or cold drink to treat anxiety. Meprobromate  was manufactured and marketed in the US as Miltown and Equanil. They were best-selling sedatives/minor tranquilizers for a time, until replaced by benzodiazepines. Nowadays, meprobromate is known to be addictive at doses not much higher than the medication dosages.

Mosaic steps at Pelegrin Courtyard farm.
Photo Pam Dawling

We saw many outdoor mosaics, including walkways, steps and pieces embedded in the walls.

Mosaic bench at Pelegrin Courtyard, Cuba.
Photo Pam Dawling

Inside the galleries we saw pottery, dolls and paintings. I bought a painting of an old man for $25.

Pelegrin Courtyard pottery.
Photo Pam Dawling

There was a big porch with a mural and greetings from groups  who had visited from all over the world.

Porch on the artists’ gallery at Pelegrin Courtyard, Cuba.
Photo Pam Dawling

They have received international support for some of their farming (irrigation) and their farm buildings.

Pelegrin Courtyard, Cuba. Outdoor classroom.
Photo Pam Dawling

Collard Greens are having their Own Week!

Collards are a southern food icon and an underappreciated nutrition powerhouse that has sustained generations of southerners, both Black and white. At last this vegetable is getting the recognition it deserves! The first ever Collards Week is happening December 14-17 2020. I found out about this while researching for an article on collards for Growing for Market magazine. Yes, perhaps the title “Week” is aspirational, and four days is a jumping-off point for the post-Covid future.

There will be online presentations celebrating collards led by Michael Twitty, Ira Wallace, Jon Jackson, Amirah Mitchell and Ashleigh Shanti. This event includes food history, seed stewardship, gardening, farming, cooking and conversation and is part of the Heirloom Collard Project. Collards Week is a collaboration between the Culinary Breeding Network and The Heirloom Collard Project. You can register for free at www.heirloomcollards.org/collard-week-2020/. All events will be broadcast live through YouTube Live via the Culinary Breeding Network starting at 1:00pm Eastern time.

Chef Ashleigh Shanti preparing collards.
Photo Chris Smith

Michael Twitty’s kick-off presentation, The History and Significance of Collards in the South, will be a fascinating exploration of complex issues. Twitty states this himself on his blog, Afroculinaria, “The collard’s complicated story with African Americans really speaks to the way food can unravel the mysteries of complex identities.”

The Collards Tour and the Book

From 2003 to 2007, a team of four crisscrossed the South, mostly in North and South Carolina, searching for heirloom col­lards by word-of-mouth, by spotting them as they drove past, and by reading newspapers, attending small-town collard festivals, and visiting restaurants where collards were the only greens served. After the trip, USDA Plant Geneticist Mark Farnham grew out more than sixty of the heirloom collard cultivars in a trial garden at a USDA Agricultural Research Station. He published several papers, including the 2007 article “Neglected Landraces of Collard from the Carolinas.”

Two of the other road trip members, Edward H Davis and John T Morgan of Emory & Henry College, wrote a beautiful book: Collards: A Southern Tradition from Seed to Table to tell the stories of these varieties and the gardeners who steward them. Davis and Morgan noted that despite other wide diversity among the collard seed savers, most of them were older, with an average age of 70, and most of them had no family, friends, or neighbors will­ing or able to keep growing their special family collard variety into the future.

The Heirloom Collards Project

In 2016, Seed Savers Exchange in collaboration with Ira Wallace at Southern Exposure Seed Exchange requested over 60 collard varieties from the USDA ARS National Plant Germplasm System (NPGS) to trial at Seed Savers Exchange, Decorah, Iowa. These were rare heirloom varieties collected by Davis and Morgan from seed savers across the Southeast. The goal of the Heirloom Collards Project is to support the tradition of heirloom collards, by finding growers and sharing the seeds nationally and also to celebrate the special stories associated with these heirloom collards.

The Heirloom Collard project is a national program led by Southern Exposure Seed Exchange, Seed Savers Exchange, Working Food and The Utopian Seed Project. The Project is building a coalition of seed stewards, gardeners, farmers, chefs and seed companies to preserve heirloom collard varieties and their culinary heritage.

Ira Wallace has an article “A Southern Food Tradition: Saving Heirloom Collards” coming out in the Jan/Feb 2021 issue of Grit magazine. There she points out that giant seed companies have been buying out the smaller ones, and have reduced the number of open-pollinated collard varieties readily available to only five.  Saving heirloom collards is an act in food heritage. Ira’s article also includes some collard stories and directions for growing seed. You can also find good directions for growing seed in Jeff McCormack’s Organic Brassica Seed Production Manual.

Mosaic photo by Chris Smith

The Heirloom Variety Trial

The National Heirloom Collard Variety Trial was launched in 2020, with over 230 participants across the US. They are currently growing twenty different varieties from the large collection at Seed Savers Exchange and the USDA. This collection includes varieties from the Davis and Morgan collecting trips. There are eight trial sites growing all 20 varieties and also hundreds of citizen scientists growing and comparing randomly selected sets of three varieties. The growers are recording data for each collard variety on appearance, uniformity, vigor, disease resistance, flavor, germination, earliness, yield and winter hardiness. Their data will be recorded and analyzed via SeedLinked, a web platform connecting people with information on varieties written by people growing them.

The Heirloom Collard Project has a place for everyone interested in growing or eating this delicious vegetable, including home gardeners, experienced seed savers, commercial growers and chefs. Click the link to see photos of the 2020 varieties and the farms doing the full trial. Get ready to sign up for 2021. Novice seed growers may want to consider practicing with more common varieties first, and then, as they gain experience, they can sign up to become seed-saving stewards.

Morris Heading collards.
Photo Kathryn Simmons

Growing collards

Collards are very easy to grow and harvest, providing months of harvests from a single sowing. They are cold-hardy and heat-tolerant, giving the possibility of harvests ten months of the year in the Southeast. Colder areas may need to provide some protection if wanting mid-winter harvests. Hotter areas may need a longer summer break. Growers can make sauerkraut to extend the season. There is a wide range of leaf shapes and colors including variegated types. For details of how to grow collards, see my article coming soon in Growing for Market.

Collard stecklings overwintering in a pot for seed saving.
Photo Seed Savers Exchange

There is a fascinating  blog post  published on the Heirloom Collard website written by Norah Hummel, who is a Seed Savers Exchange partner in the Heirloom Collards Project. It’s a really fantastic blog post with some really good photographs, talking you through the whole process of growing collard seed.

Growing Collard Seed

Like other brassicas, collards are a biennial seed crop. To save seed, keep your collard plants alive over winter. If you can’t do this outdoors or in a hoophouse, dig up the plants in late fall and trim off the leaves, preserving the growing point. Replant these plant stubs (stecklings) close together in a tub of soil or even damp sawdust, to replant in early spring. Make sure you have no other brassicas from the oleracea group (Brussels sprouts, cabbage, cauliflower, some kales, kohlrabi) in flower at the same time. Some kales (Russian, Siberian types) are Brassica rapa and do not cross-pollinate.

Winnowing collard seed with a box fan.
Photo Southern Exposure Seed Exchange

Read Margaret Roach’s interview on A Way to Garden, with Chris Smith of Utopian Seed Project, a crop-trialing nonprofit working to celebrate food and farming, and Sow True Seeds, talking about heirloom collards.

Cooking Greens in April

Cooking Greens to Harvest in Central Virginia in April

Out with the old! In with the new!

A bed of spring Senposai.
Photo by Wren Vile

Outdoors, collards, kale and spinach that have over-wintered will be coming to an end. Most years, the collards and then the kale bolt in mid-late March, and the overwintered spinach in April.

Fast growing crops like mustard greens and senposai from spring transplanting will be ready to harvest as leaves from early April; collards and kale from mid-April. Beet greens might be ready at the end of April, or it might be May before we get those, depending on the weather and our sowing dates.

From the hoophouse, we are getting the last of most of our indoor greens. The Russian kale, the chard and the Frills (frilly mustards) are bolting. We do have spinach we sowed in January, which will continue all this month. The Bulls Blood beet leaves no longer look very appetizing, but we could cook those up early in the month. The milder winter means earlier bolting this year.

Cooking Greens to Sow in Central Virginia in April

Bright Lights chard in our garden in July.
Photo Pam Dawling

Chard is our best summer cooking green. Chard (Beta vulgaris var. cicla) is the same species as beetroot and, like beets, is a biennial. Hence it will not flower until the second year after planting, and can provide fresh greens all summer and fall, until halted by hard frosts. Even then, the root may survive and regrow the next spring. Leaf beet, also known as perpetual spinach, is a chard, with thinner stems and smaller leaves than most Swiss chard. It is the closest in flavor to spinach for growing in hot weather

Leaf Beet (Perpetual Spinach)
Photo Fedco Seeds

If you prefer spinach in spring, as we do, grow that first, and switch to chard for summer, sowing in plug flats or soil blocks three weeks before your last frost date. (We sow March 24-April 6)

If you want chard in spring, you can start flats earlier or direct seed outdoors two or three weeks before the last frost date.

We also use beet greens for cooking, although our main purpose is to grow beets. Our last date for sowing beets in spring is 4/15.

There are other hot weather greens you could sow in central Virginia and warmer climates.

In the hoophouse, it is definitely too late to plant cooking greens. Anyway, we are filling the tunnel with early tomatoes, squash, cucumbers, and peppers.

Cooking Greens to Transplant in Central Virginia in April

Broccoli head after rain
Photo Wren Vile

Outdoors, we transplant our main cabbage and two sowings of broccoli under nets or rowcover within 6 weeks of sowing. Rowcover is our usual choice, because changeable weather and late frosts are more of an issue here in spring than bugs are. It is important to protect young cabbage and broccoli with 5-8 true leaves from cold stress (<40°F/4.5°C for a few days, or longer at 50°F/10°C). At this stage they are particularly sensitive to cold, which can cause early bolting (and very low yields). After a few weeks, when the weather is more settled, we move the rowcover to newer, more tender crops.

Mid-April: We use saved extra transplants to fill gaps in the broccoli and cabbage plot, at the same time planting out alyssum every 6’ (1.8 m) in the center of the beds. These little flowers attract beneficial insects (see more below).

Ruby Red chard.
Photo Kathryn Simmons

Late in April we will transplant leaf beet and chard – it doesn’t take long for the seedlings to grow. Often we cover the prepared bed with hay mulch, then make two rows of “nests” in the 4’ (1.2 m) wide beds. We don’t space the rows evenly across the bed, but bunch them in close to each other in the middle. This saves the paths for us to walk down.

In the hoophouse, in very early April we use young spinach transplants to fill gaps only in the outer thirds of the beds, leaving the bed centers free for the tomatoes, etc. It would be better to have done this in late February and March, but this year we didn’t get to it. We won’t get high yields, planting this late.

Other Cooking Greens Tasks in Central Virginia in April

Early April: We move rowcover from turnips, senposai, early cabbage, kohlrabi and onions as needed for the broccoli and the maincrop cabbage.

Mid-April: We move rowcover from spring-planted kale, collards, mustard and early lettuce for the tender crops. We finish filling gaps in the broccoli and cabbage plot, at the same time planting out alyssum (sown March 3) one plug every 6’ (1.8 m) in the center of the beds. See the Special Topic for April below, for more on farmscaping, as this method of pest management is called.

Early spring cabbage with alyssum to attract beneficial insects.
Photo Pam Dawling

Late April: We move rowcovers from for the broccoli and the maincrop cabbage. With broccoli, the first weeks after transplanting are vegetative growth, adding leaves until there are about 20, when “cupping” starts — the leaves start to curl up, forming a convex shape rather than growing straight out. The cupping stage is usually10-14 days before harvest starts, depending on temperature. If the weather gets too hot — more than 80°F (27°C) — too soon, the broccoli may grow only leaves, and not head up.

In the greenhouse, we start to have less work, which is fortunate as outdoor work increases.

Special Cooking Greens Topics for April: Farmscaping for Brassicas

Farmscaping is the inclusion of specific flowers to attract beneficial insects. The pollen and nectar offer an alternative food source to beneficial insects when their insect prey is scarce. And if their insect prey is right by the flowers, what could be better?

Alyssum.
Photo Raddysh Acorn

We plant Sweet Alyssum in our spring broccoli patch to attract predators of aphids and caterpillars; Putting 5 percent of the crop area in plants that attract beneficial insects can seriously reduce pest numbers. Sweet alyssum, yarrow, dill, coriander (cilantro), buckwheat, mung beans, other peas and beans, black oil-seed sunflower, calendula and cleome all work well to attract a range of insects (especially ladybugs and lacewings) that eat or parasitize aphids. Pans of water and gravel will help attract aphid midges and lacewings. The gravel provides surfaces for the insects to land on while drinking. Farmscaping can make other insect control unnecessary in a good year. Beneficials will generally move up to 250 feet (75 m) into adjacent crops.

We also plant “insectaries” around the garden, usually at the ends of beds with crops that will be growing for several months. These flowers are planted inside rings sawn from a plastic bucket. The rings alert the crew that something special is there, not just a clump of weeds. Mix flowers to have something blooming all the time.

Insectary circle with sunflower, tithonia, borage, zinnia.
Photo Pam Dawling

Another method for incorporating farmscaping is to plant beneficial-attracting perennial flowers in areas that are too challenging to use for production: edges, slopes, tight corners, hedgerows, and field borders.

Other Pest Management for Brassicas

Using rowcovers keeps many pests off the plants while they are small. We have not had much trouble with aphids, perhaps partly because our overhead sprinklers wash them off and they can’t travel far. Insecticidal soap sprayed three times, once every five days, can usually deal with aphids. Our worst pest is the harlequin bug. For lack of a better organic solution, we handpick them. Ladybugs are reputed to eat harlequin bug eggs.

Sometimes we have had enough cabbage worms to make Bt (Bacillus thuringiensis) necessary, but usually paper wasps eat the caterpillars. The action level threshold is an average of 1 cabbage looper, 1.5 imported cabbageworms, 3.3 armyworms or 5 diamondback moth larvae per 10 plants. Below this level you can do watchful waiting rather than spraying with Bt or spinosad. We are lucky enough to have the naturally occurring wasp parasite of cabbage worms, the Braconid wasp Cotesia species, which are found as small cottony white or yellowish oval cocoons in groups on brassica leaves. The Cotesia wasps like umbelliferous flowers, and overwinter on yarrow as well as brassicas. If you find Cotesia cocoons in the fall and your brassicas aren’t diseased, you can leave plants in the field over winter. Or you could collect up leaves with cocoons in late fall and store them at 32°F–34°F (0°C–1°C) until spring. Hopefully no one will clean out your fridge without checking.

Richard McDonald has good information in his Introduction to Organic Brassica Production. He reports that broccoli plants with six to sixteen leaves (just before cupping) can lose up to 50 percent of their leaf area without reducing yield. Moderate defoliation (20–30 percent) causes the plant to exude chemicals that attract parasitic wasps and predatory insects. If you relax and allow this amount of defoliation early on, you can encourage these beneficial insects to move in and begin foraging in the area. Once the plants cup, you want to prevent further defoliation by having the most beneficials and the fewest pests on site. If pest levels are above the action threshold, cupping is the stage to take action, and probably not earlier.

Broccoli side shoots offer harvest after the main head is cut.
Photo Nina Gentle

To float out worms and aphids after harvest (before cooking!), use warm water with a little vinegar and soak for up to fifteen minutes, then rinse.

Fast Growing Vegetables

Lettuce bed in May.
Photo Wren Vile

Maybe part of your response to Covid-19 is to grow more of your own food, and you are wondering what can bring fastest results. Or maybe you just want to leap into spring and have early harvests. Either way, here is information on some vegetable crops that offer fast returns; ways to get crops to grow faster; ways to get more crops from a small space and some sources for more information.

Vegetable Crops That Offer Fast Returns

In my blog post If Spring is Too Wet in March 2019, I included a paragraph on fast crops.

  • Ready in 30–35 days from sowing are baby kale, mustard greens, collards, radishes, spinach, chard, salad greens (lettuce, endives, chicories) arugula, and winter purslane. Beet greens from thinnings can be cooked and eaten like spinach.
  • Many Asian greens are ready in 40 days or less: Chinese Napa cabbage, Komatsuna, Maruba Santoh, mizuna, pak choy, Senposai, tatsoi, Tokyo Bekana and Yukina Savoy). See my Asian Greens of the Month category of posts. There’s a huge range of attractive varieties, they’re better able to germinate in hot weather than lettuce, and faster growing than lettuce. Most reach baby salad size in 21 days, full size in 40 days. Transplant 4-5 weeks after spring sowing, or direct sow. Nutritious as well as tasty. Flavors vary from mild to peppery; colors cover the spectrum: chartreuse, bright green, dark green and purple. A diversity of crops without a diversity of growing methods! Grow when you normally grow kale. Be aware that Asian greens sown in spring will bolt as soon as the weather heats up, so be ready to harvest a lot at once (if you planted a lot, that is!) You can make Kim Chee.
  • Tatsoi and our August sown catch crop of Tokyo bekana.
    Photo Pam Dawling
  • One summer we sowed Tokyo Bekana as a lettuce substitute. 20 days to baby size, 45 days to a (large) full size. We have also grown this at other times of year, when faced with an empty space we hadn’t planned for.
  • Mizuna and other frilly mustards are very easy to grow, and tolerate cold wet soil to 25°F (-4°C). In addition, they are fairly heat tolerant (well, warm tolerant). Use for baby salads after only 21 days or thin to 8″–12″ (20–30 cm) apart, to grow to maturity in 40 days. Mild flavored ferny leaves add loft in salad mixes and regrow vigorously after cutting.
  • Also ready in 30–35 days are spinach, chard, salad greens (lettuce, endives, chicories) and winter purslane.
  • Ready in 35–45 days are baby carrots (thinnings or the whole row), turnip greens (more thinnings!) endive, corn salad, land cress, sorrel, parsley and chervil. Some of the faster smaller turnip roots can also be ready in 45 days or less.
  • Ready in 60 days are beets, dwarf snap peas, broccoli, collards, kohlrabi, turnips and small fast cabbages (Farao or Early Jersey Wakefield).
  • Also ready in 50-60 days once we are past frosts: zucchini, yellow squash, bush beans, small cucumbers can grow fast.
  • Garlic scallions can be grown over-winter, but will grow quickly in spring. Plant scrappy little garlic cloves you don’t want to cook with in close furrows and wait till the leaves are 7” (18 cm) tall before digging up the plant and preparing like onion scallions (spring onions). Can be eaten raw, but more often cooked. You can also plant whole bulbs without separating the cloves. This is a good use for extra bulbs that are already sprouting in storage.
Our garlic scallions in February. we usually space the rows much closer than this. We’ll start harvesting when they reach 7″ in height.
Photo Pam Dawling
  • See other blog posts in my Cooking Greens for the Month series, and Asian Greens for the Month, as well as Lettuce of the Month
  • Try Eat-All Greens, an idea form Carol Deppe. Patches of carefully chosen cooking greens are sown in a small patch. When it reaches 12″ tall, Carol cuts the top 9″ (23 cm) off for cooking, leaving the tough-stemmed lower part, perhaps for a second cut, or to return to the soil.
Twin Oaks Eat-All Greens on October 19.
Photo Bridget Aleshire
  • Spinach is good for salad or cooking uses. Be aware that the fastest biggest spinach may not last long once it warms up! We have found Acadia and Reflect have good bolt-resistance from outdoor spring sowings.

Fast Varieties of Lettuce and Greens

Bronxe Arrow lettuce.
Photo by Southern Exposure Seed Exchange
  • Grow the right lettuce variety for the conditions. Ones that do well in early spring are often useless here after the end of March, or even mid-February. I like to sow 4 varieties each time (for the attractive harvests, and to reduce the risks if one variety bolts or suffers disease): at least one red and one romaine. We have 5 lettuce seasons, with different varieties:
    • Early Spring (Jan – Mar), 6 sowings
    • Spring (April – May 15), 5 sowings
    • Summer (May 15 – Aug 15), 17 sowings (lots of seed!)
    • Fall (Aug 15 – Sept 7), 9 sowings
    • Winter Sept 8 – 27, 9 sowings
  • Baby lettuce mix can be ready in as little as 21 days from mid-spring to mid-fall. A direct-sown cut-and-come-again crop, the plants regrow and can be harvested more than once in cool seasons. Weed and thin to 1″ (2.5 cm). When 3″–4″ (7.5–10 cm) tall, cut 1” (2.5 cm) above the soil. Gather a small handful in one hand and cut with using large scissors. Immediately after harvesting, weed the just-cut area so the next cut won’t include weeds
  • Leaf lettuce can be harvested by the leaf much sooner than waiting for a whole head of lettuce.
  • Small-leaf lettuces (aka Eazyleaf, One-Cut, Multi-Cut, Multileaf): Johnny’s Salanovas, Osborne’s and High Mowing’s Eazyleaf; Tango, Oscarde, and Panisse (older varieties) too. Full-size plants can be harvested as a head, or harvested with a single cut, providing a collection of bite-sized leaves. Or just one side (or the outer leaves) of the plant can be cut and the plant will regrow for future harvests. Growing multileaf heads takes 55 days, compared to 30 days for baby lettuce.
Buckley red oakleaf single-cut multi-leaf lettuce.
Photo High Mowing Seeds
  • Other greens can be sown in close rows for harvesting as salad crops at a height of 3”-4” (7-10 cm). These are called mustard mixes or brassica salad mixes.
  • Many cooking greens can be used as salad crops while plants are small, as you thin the rows of direct-sown crops.

Ways to Get Crops to Grow Faster

  • Sow when the conditions are right. Soil temperature is important. I have a table of soil temperatures in Year-Round Hoophouse on page 208. Vegetable Seed Germination: Optimum soil temperatures for germination and days to emergence, where known.
  • Grow transplants. By starting your plants in a place with close-to-ideal temperatures, rather than direct-seeding when it’s still a bit too chilly outside, you’ll get bigger plants sooner. You’ll also buy time to prepare the soil where you are going to plant out.
  • Find warm sheltered micro-climates, in front of a south-facing wall for example.
  • Make your own warm sheltered micro-climates with rowcover or low tunnels.
  • Take advantage of plastic mulch to warm the soil, for crops that like warmth. Regular black plastic mulch will need to be removed at the end of the growing season, but biodegradable mulch does not. However, if you are taking over part of your yard near your house, I should tell you that you will see shreds of the bioplastic next year. See Setting out biodegradable plastic mulch by hand
Rolling biodegradable plastic mulch by hand
Photo Wren Vile
  • Consider landscape fabric with planting holes burned in, as a reusable alternative to throw-away or biodegradable mulch.
  • Use mixes for salads: Our general salad mix harvesting approach is to mix colors, textures and crop families. I like to balance lettuce of different kinds with chenopods (spinach, baby chard, Bull’s Blood beet leaves) and brassicas (brassica salad mix, baby tatsoi, thinnings of direct-sown brassicas, chopped young leaves of Tokyo bekana, Maruba Santoh or other Asian greens, mizuna, other ferny mustards such as Ruby Streaks, Golden Frills and Scarlet Frills). See Making salad mix
  • Microgreens: See Andrew Mefferd The Greenhouse and Hoophouse Grower’s Handbook.
  • When the weather warms up, consider using shadecloth for heat-sensitive plants, particularly lettuce, but any of the cool weather greens you still have by then.
  • In warm weather, greens and lettuces inside a tipi of pole beans will benefit from the shade.

Ways to Get More Crops from a Small Space

  • With transplants, you can fit more crops into each bed throughout the season, because each crop is occupying the bed for less time than if direct-sown.
  • Transplanting can help you grow more successions of summer crops, as each one needs less time in the garden or field.
  • Grow a vertical crop on a trellis and something short in the space below it. You can even use the same trellis twice, growing tomatoes after peas, for instance.
Spinach and peas in a relay planting scheme.
Photo Twin Oaks Community
  • Relay Planting is a method of growing short crops alongside taller ones. We have often sown peas down the center of a bed of overwintered spinach. As the peas grow tall, we trellis them, and continue harvesting the spinach. When the spinach bolts, we pull it up. This overlap of bed use lets us get more crops from a bed in less time than if we sowed the crops one after another. We have also sowed peanuts down the middle of a bed of lettuce on the same date we transplant the lettuce. We make sure to use vertical romaine lettuces rather than sprawly bibbs or leaf lettuces. We have transplanted okra down the middle of a bed of early cabbage. This does involve breaking off outer leaves of the cabbage if they are about to smother the okra.
  • Sow some slower-maturing crops the same time as you sow the fast ones, so you have food later as well as sooner! Carrots, turnips, cabbages, broccoli, collards, kohlrabi,
  • Sow some multiple-harvest crops to save work later. Greens that are harvested by the leaf, rather than the head, offer good value.

Sources for More Information

  • In High-Yield Vegetable Gardening, Colin McCrate and Brad Halm point out that when planning what to grow, it’s important to consider how long the crop will be in the ground, especially if you have limited space.
  • Cindy Conner in Grow a Sustainable Diet: Planning and Growing to Feed Ourselves and the Earth, leads you through the process of identifying suitable crops for food self-reliance, and provides a worksheet to help you determine Bed Crop Months. For each bed, determine how many months that food crop occupies that bed and so assess the productivity value of one crop compared with another. Short season crops grow to harvest size in 30-60 days, allowing series of crops to be grown in the space, and feeding people quickly. If all your nutrients are to come from your garden, you will need to pay attention to growing enough calories. Otherwise you’ll lack the energy to get to the end of the season!
  • Curtis Stone, in The Urban Farmer, distinguishes between Quick Crops (maturing in 60 days or less) and Steady Crops (slower maturing, perhaps harvested continuously over a period of time). He has designed a Crop Value Rating system based on 5 characteristics. To use this assessment, you look at each characteristic and decide if the particular crop gets a point for that characteristic or not. Then look for the crops with the highest number of points. Spinach gets all 5 points; cherry tomatoes only 3. The smaller your farm, the higher the crops need to score to get chosen. His 5 are:
  1. Shorter days to maturity (fast crops = chance to plant more; give a point for 60 days or less)
  2. High yield per linear foot (best value from the space; a point for1/2 pound/linear foot or more)
  3. Higher price per pound (other factors being equal, higher price = more income; a point for $4 or more per pound)
  4. Long harvest period (= more sales; point for a 4 month minimum)
  5. Popularity (high demand, low market saturation)
  • Steve Solomon in Gardening When it Counts provides tables of vegetable crops by the level of care they require. His Easy List: kale, collards, endives, chicories, spinach, cabbage, Irish potatoes, sweet potatoes, all cucurbits, beets, chard, sweet corn, all legumes, okra, tomatoes (followed by the more difficult eggplant, peppers).
  • See my blog post How to Decide Which Crops to Grow
  • See my article Intercropping: Minimize Your Effort While Maximizing Yields, in the Heirloom Gardener of Spring 2018.
  • Jennifer Poindexter on the Morning Chores Site has a nice simple web post on 16 Fast Growing Vegetables That Will Give You a Harvest Quickly
  • Steve Albert on the Harvest to Table website has a good post on Quick-Growing Vegetable Crops. It includes recommended fast-growing varieties of 29 crops.

Winter-Kill Temperatures of Cold-Hardy Vegetables 2020

Overwintered Vates kale in central Virginia in March.
Photo Nina Gentle

At the Organic Association of Kentucky Conference, I gave a a presentation on Winter High Tunnel and Outdoor Vegetable Production. You can see it here. Click on the diagonal arrow icon to see it full screen, then click on the right pointing triangular arrow

Winter-Kill Temperatures of Cold-Hardy Vegetables 2020

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

The winter 2019-2020 has been mild, with our lowest temperature being a single night at 12°F (-11°C). The Koji became completely unmarketable but did not completely die. Yukina Savoy is indeed hardier, being OK down to 10°F (-12°C). We had one night at 13°F (-10°C) and two each at 17°F (-8°C), 18°F (-8°C also) and 19°F (-7°C).

This winter I noted the death of rhubarb stems and leaves at 25°F (-4°C), rather than 22°F (-6°C), as I noted a year or two ago.

In early January 2018, we had some extremely cold temperatures of -8°F and -9°F (-22°C and -23°C). The winter of 2018-2019 was not as brutal. Our lowest temperatures were 6°F (-14°C) in late January, 8°F (-13°C) in December 2018 and a couple of 11°F (-12°C). I found that senposai is more cold-tolerant than I had thought. Averaging our winter low over those three winters gives 3.2°F (-16°C), completely within the zone 7a range.

My other results from other years still hold up.

I also learned that there is more damage when the weather switches suddenly from warm to cold. And that the weatherman in Raleigh, NC says it needs 3 hours at the critical temperature to do damage.

Radicchio seeds from Seeds from Italy

Notes on Chicories and Endives

We gave up growing chicories and endives because we really didn’t like the bitterness. I decided to do some more online research to make sure I wasn’t spreading untruths. Chicories and endives fall into two groups, but they are confusing because the common names sometimes suggest the opposite group than they are botanically. Here’s the best info I have. If you know differently, please leave a comment.

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

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

Using the List

Unless otherwise stated, these are killing temperatures of crops outdoors without any rowcover. All greens do a lot better with protection against cold drying winds. Note that repeated cold temperatures can kill crops that can survive a single dip to a low temperature, and that cold winds, or cold wet weather can destroy plants quicker than simple cold. Your own experience with your soils, microclimates and rain levels may lead you to use different temperatures in your crop planning.

Hoophouse beds in November.
Photo Ethan Hirsh

Hoophouse Notes

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

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

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

Young Bright Lights chard.
Photo Pam Dawling

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

Outdoor killing temperatures of crops (unprotected unless stated)

35°F (2°C):  Basil.

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

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

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

Tokyo bekana in our hoophouse.
Photo Twin Oaks Community

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

20°F (-7°C): Some beets (Bulls Blood, Chioggia,), broccoli heads (maybe OK to 15°F (-9.5°C)), Brussels sprouts, some cabbages (the insides may still be good even if the outer leaves are damaged), some cauliflower varieties, celeriac, celtuce (stem lettuce), some head lettuce, some mustards/Asian greens (Tendergreen, Tyfon Holland greens), flat leaf parsley, radicchio, both Treviso and Chioggia, radishes (Cherry Belle), most turnips (Noir d’Hiver is the most cold-tolerant variety).

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

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

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

Young Cylindra beets.
Photo Wren VIle

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

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

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

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

Garlic shoots in January.
Photo Pam Dawling

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

Crimson clover is hardy down to 0°F (-18°C) or slightly colder

 -5°F (-19°C): Leaves of overwintering varieties of cauliflower, Vates kale survives although some leaves may be too damaged to use.

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

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

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

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

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

Cooking Greens in March

 

White Russian kale in our hoophouse in March.
Photo Pam Dawling

Cooking Greens to Harvest in Central Virginia in March

Eat Your Greens! More Bolting Greens in the Hoophouse, Sigh.

Outdoors, we can still harvest collards, kale and spinach. We also have very nice spinach in our coldframes, where the crop gets better protection from the cold than the outdoor beds.

From the hoophouse, in the cooking greens department, we still have plenty of Bulls Blood beets (the leaves are getting a bit big and leathery for salads), chard, frills (frilly mustards such as Ruby Streaks, Golden Frills, Scarlet Frills), White and Red Russian kales, and spinach.

In the hoophouse, the extra warmth (at last!) and the considerably lengthening days are causing lots of the greens to bolt. This year our turnips, tatsoi, senposai, and the Koji were all bolting before the end of February, although other years these have not bolted until mid-March (or the later sowings at least). We are harvesting lots of greens, trying to eat them all before we lose them!

We are keeping an eye on our Russian kales, chard, beet greens and later spinach sowings. They usually last till late April or even early May, but this milder winter may mean they will bolt earlier this year.

Cooking Greens to Sow in Central Virginia in March

Outdoors in early March, or preferably mid-February we direct sow spinach if our January transplant sowings failed. This year, we have plenty of transplants. In early March we sow turnips, and give them rowcover.

In the greenhouse in early March, we sow broccoli #3, in open 3” (7.5 cm) flats. This sowing is intended as a gap-filler for the first two sowings, if any plants die after transplanting, or if we don’t get enough plants from the first two sowings.

Winstrip tray with chard seeds.
Photo Pam Dawling

In late March, we sow sow chard and leaf beet. Leaf beet, also known as perpetual spinach, is a chard, with thinner stems and smaller leaves than most Swiss chard. It is the closest in flavor to spinach for growing in hot weather that I have found. Because it is a biennial, it will not bolt the first year.

In the hoophouse, we do not usually sow any cooking greens. Because the hoophouse is much warmer on sunny days, annual greens (all the brassicas) will quickly bolt. We do better to focus on outdoor planting.

Cooking Greens to Transplant in Central Virginia in March

Outdoors, we transplant cabbage #1 from flats in early March (3/10). These are fast-growing early varieties such as the hybrid Farao (65 days) and the OP Early Jersey Wakefield (63 days). This year we are also trying the larger but slower Early Flat Dutch (85 days)

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

In mid-March, we transplant collards, mustard, kale (last date 4/1), and senposai. We use rowcover over all our early transplants outdoors, for a few weeks until the weather is milder. By then, we usually need the rowcover somewhere else for new transplants or sowings.

It is important to protect young cabbage and broccoli with 5-8 true leaves from cold stress (<40°F/4.5°C for a few days, or longer at 50°F/10°C). At this stage they are particularly sensitive to cold, which can cause early bolting (and very low yields).

In the hoophouse, after February 20 we use young spinach transplants to fill gaps only in the outer thirds of the beds, leaving the bed centers free for tomatoes, etc. in mid-March.

Other Cooking Greens Tasks in Central Virginia in March

Open flat of broccoli seedlings.
Photo Wren Vile

In the greenhouse, we are busy spotting (see February Special Topic) all our plants to give them two weeks of greenhouse protection and 10-14 days in the coldframe before their transplant date. During early to mid-March, this means the senposai, mustard, broccoli and main crop cabbage, as well as collards and kale (if we don’t have enough of those for bare-root transplanting from the hoophouse).

Special Cooking Greens Topics for March: Trap Flea Beetles, Extra Month of Greens in the Hoophouse

A row of mustard greens can be used to lure flea beetles.

They like the pungent compounds in brassicas.  Once you have lured the flea beetles you need to deal with them before you create a flea beetle breeding ground. Flaming the mustard plants is one possibility. If you have poultry that likes eating flea beetles, you could cut off some of the leaves and carry them to the chicken run. Bug vacuums are also a possibility. Another approach is to hold an inverted bucket lined with sticky trap compound over the plants and rap the stems with a stick. If you’re lucky, the pests will stick in the bucket.

North edge bed in our hoophouse flagged up for digging holes to plant peppers.
Photo Pam Dawling

Hoophouse transition to give an extra month of greens.

Preparing our hoophouse beds for our early tomatoes, peppers, cucumbers and squash is very different from our fall bed prep for winter greens. We stretch a long tape measure down the center of each bed, and put a flag every 2 ft (60 cm). All our transplanted crops in spring are at this spacing. We then prioritize harvesting the greens which are close to the flags. A day or two before transplant day, we dig a hole at each flagged spot and add a shovelful of compost to each hole. After transplanting the new crop plants, and watering them in, we start harvesting the greens directly to the south (in front of) the new plants. As the plants get larger, we pull more of the greens between the transplants. Anything that is touching leaves is too close and has to go. After a few weeks we also need to harvest the last of the greens, to the north of the transplants, which by then have reached a good size. This method gives us an extra month of greens and initially the relatively large greens protect the small transplants from too much direct sun or from cold breezes. If the night will be frosty, we pull rowcover over the beds – the greens hold the rowcover off the tender plants.

Tomato plants in our hoophouse, in early April, planted among the winter greens
Photo Kathryn Simmons

Cooking Greens in February

Plentiful spinach in our cold frame in winter.
Photo Wren Vile

Cooking Greens to Harvest in Central Virginia in February

Harvest in Time! Lots of Bolting Greens in the Hoophouse!

Outdoors, we can still harvest collards, kale and spinach. This winter our chard has died. Remember that red chard is hardier than multi-colored and green chard is hardier still. To maximize your chance of keeping chard alive over the winter, use hoops and rowcovers (in zone 6-8) or, in colder zones, cut the tops off the plants (above the growing point) before it gets much below 15F (-9C), remove those leaves, then cover the bed with a mulch of thick straw, hay or tree leaves. Mulching doesn’t work in milder climates, especially those with back-and-forth temperatures) because new growth forces up out of the mulch and gets killed.

From the hoophouse we continue harvesting chard, Frills, kale, senposai, spinach, tat soi, turnip greens, and also yukina savoy (if we had it). We normally grow the Frills as salad crops, but once they get large and plentiful, we can cook some.

Bolting Golden Frills and Scarlet Frills.
Photo Pam Dawling

In the hoophouse, the extra warmth (sometimes!) combined with the reliably lengthening days causes some of the greens to start bolting. In January, I told you the order of bolting of our hoophouse greens. Our Koji has all bolted by February 1, and I pine for Yukina Savoy which usually lasts till early-mid March here, from our second winter sowing. We didn’t have any this winter.

We are keeping an eye on our turnip greens #1 (they will bolt in mid-February); tatsoi #2, spinach #1, and turnip greens #2 (usually bolt in early March). Our senposai and our turnips #3 usually don’t bolt till mid-March. Our Russian kales, chard, beet greens and January spinach sowings last till late April or even early May.

Hoophouse turnips have delicious greens too!
Photo Wren Vile

Cooking Greens to Sow in Central Virginia in February

Outdoors in mid-February, we sow spinach if our January transplant sowings failed. We presprout 4oz/bed spinach for 1 week before sowing. This rarely needs to happen, as we have a backup transplant sowing date to seed in flats in the greenhouse, if our first-line hoophouse sowing of transplants doesn’t come up well. This year, those look great!

In the greenhouse in early February, we sow: kale, cabbage, mustard, collards, senposai, broccoli #1, kohlrabi in open 3” (7.5 cm) flats.

In late February, we sow broccoli #2. This year we have reduced the size of our planting to make it more manageable.

In the hoophouse, December 15-February 15 is the slowest growing time. We do sow some salad crops, but not usually any cooking greens. if the January hoophouse sowings of kale and collards have come up well, we don’t need to sow those in the greenhouse this year.

We have a couple of unexpected gaps this year. We followed Radish #2.5 (an extra sowing we squeezed in on October 20) with Frills (frilly mustards) and we plan to follow some of our Koji #2 with a quick catch crop of Tokyo Bekana, marking five rows in the bed, but leaving the central row unsown. This will hopefully let us leave the greens growing after we transplant the warm weather crops down the centerline of the bed.

Young Ruby Streaks, Golden Frills and Scarlet Frills provide continuous harvest after the older ones bolt.
Photo Pam Dawling

Cooking Greens to Transplant in Central Virginia in February

Outdoors, we transplant spinach from hoophouse [or flats] in early February

In the hoophouse, from January 25 to February 20 we fill gaps that occur in the beds with spinach wherever the gaps are, using the spinach Filler Greens which were sown October 24 and November 9 (spinach). We’re careful not to fill any places that will be sown in new crops in February, such as where we sow a row of early snap peas, or the salad crops I mentioned earlier.

From February 20, we only transplant spinach to fill gaps on the outer thirds of the beds, leaving the bed centers free for tomatoes, etc. in mid-March.

Other Cooking Greens Tasks in Central Virginia in February

Flats of cabbage in our greenhouse in February.
Photo Pam Dawling

In early February in the greenhouse we spot cabbage and kale. In late February, we spot senposai, cabbage #2 and collards. See the Special Topic below for more about the task we call ”spotting”. Other names for this task include “bumping up”and “pricking out.”

We really try to finish transplanting spinach outdoors, as our springs are short and quickly heat up, taking the spinach plants with them.

We weed our over-wintered spinach, kale and collards. Hoeing isn’t so effective in early spring, as the chickweed, henbit and dead nettle too readily re-root on damp soil. Hand-pulling weeds is slow, but more effective. Another approach is to hoe several times, choosing dry breezy sunny days.

During January we had two nights at 13F (-10.5C) and 12F (-11C). The Koji are looking quite damaged, beyond marketable but not beyond salvageable for home use. We grew too much of this, so we still have plenty to eat! The outdoor senposai is also damaged, but as this is a loose-leaf crop it could recover if it doesn’t get colder.

As I reported in January, we didn’t cover the spinach this winter, because of issues with rowcover fibers getting in the food. The plants are looking quite small, while those in the coldframes (with rowcover) are growing well. I have been expecting the growth of the uncovered spinach to be a lot slower, as spinach (like kale and lettuce) makes some growth whenever the temperature is 40°F (4.5°C) or more. 10°F (-12°C) could kill the large leaves and 5°F (-15°C) can kill spinach entirely. So far, temperatures haven’t get that cold this winter.

Weeding rowcovered spinach in winter. This winter we tried not using rowcover.
Photo Wren Vile

Special Cooking Greens Topic for February:

Planning our Field Planting Schedule.

In January we prepare our new Seedlings Schedule, then our complex Fall Brassica Spreadsheet and Map, Field Planting Schedule, Hoophouse Schedule for March to September crops (those are not cooking greens!), and then our Raised Bed Plan and our monthly Garden Calendar.

Field Planting Schedule:

We allow 6 hours. We bring the previous year’s greenhouse copy of the Seedlings Schedule, the shed copies (the copies we wrote notes on) of the previous year’s Field Planting Schedule and the shed and seed bucket copies of the Lettuce Log. We also bring the new (current year’s) Fall Brassica Schedule, Seedlings Schedule, Seed Order, Garden Plan, Rotation Plan, Maps, Succession Crop Plan, Sweet Corn Plan, Brassica Plan and Tomato Plan and any notes we made while doing the year’s planning so far.

  1. We work in Excel, copying last year’s Schedule to a new Worksheet and modifying that.
  2. We highlight and clear the contents of the“Location” column (Crop rotation in action!)
  3. We check against last year’s Shed copy and Field Manual copy of the Field Schedule. As we go, we make a list of questions or points to fix later.
  4. We check against the Seedlings Schedule for last year and the current year, for transplant date and varieties, row feet of the transplanted crops. (Leave the direct seeded crops varieties and row feet for step 6).
  5. Next we highlight the data, sort alphabetically by Vegetable, Variety to make the next stages easier.
  6. We check against the Seed Order (and Succession Plan as needed) for varieties and row feet of direct seeded crops.
  7. We check against the Tomato Plan for main crop and late bed.
  8. We check against the Garden Rotation Plan, Maps and Succession Crop Plan.
  9. We fill gaps in the Location column, in In-row Spacing and Space Between Rows cols.
  10. We check against Fall Brassica Schedule from the current or previous year, revising sowing dates, row feet, transplanting dates.
  11. We check against the Lettuce Log.
  12. We check against Hoophouse Schedule, for transplants in and out.
  13. We clean up the Notes column keeping useful info, adding any new useful info, checking against running list of things to fix.
  14. With all that done, we sort by Transplant date; then by Vegetable, then by Variety.
  15. We tidy up the page layout and print a draft copy
  16. We proofread and fix anything that didn’t make sense.

 

Cooking Greens in January

Morris Heading collards, a reliable winter crop. Photo Kathryn Simmons

Cooking Greens to Harvest in Central Virginia in January

Harvest in time! Freezing or Bolting Greens!

Outdoors, the temperatures continue to get colder in January. In our garden outdoors, there are collards, kale, spinach, and sometimes chard,  senposai, and Yukina savoy, and over-wintered cabbage (not for much longer!).

Hopefully there is also cabbage stored in the cooler. The most cold-hardy greens are what we depend on for the next two months.

Tatsoi in our hoophouse in December.
Photo Kathleen Slattery

From the hoophouse we continue harvesting chard, Chinese cabbage, kale, frilly mustards, pak choy, senposai, spinach, (including thinnings from the newer sowings),   tatsoi (thinnings from the newer sowings, whole plants from the September 7 sowing), Tokyo bekana/Maruba santoh plants, turnip greens, yukina savoy.

In the hoophouse, the extra warmth combined with the lengthening days causes some of the brassicas to start bolting. After the Winter Solstice the order of bolting of our hoophouse greens is: tatsoi #1 (meaning, our first sowing 9/6), Tokyo bekana, Maruba santoh (all in early January); pak choy, Chinese cabbage, Yukina Savoy #1 (late January); turnip greens #1 (mid-February); Komatsuna, Yukina Savoy #2, tatsoi #2, spinach #1, turnip greens #2 (early March); Senposai, turnips #3, (mid-March); Russian kales (early April); chard, beet greens, later spinach sowings (late April or even early May.)

Tokyo bekana in our hoophouse in late December.
Photo Pam Dawling

Our knowledge of what will bolt first informs our plan of where to put the new crops we want to plant. To make space to sow spinach on 1/16, we need to clear the Tokyo bekana (and Maruba santoh) and the first tatsoi by 1/14. We keep a close eye on the Chinese cabbage and pak choy. Normally these will bolt in January, and we harvest the whole plants this month. They will be followed by sowings of kale and collard starts for outdoors on 1/24.

Chinese cabbage in November, not yet fully headed.
Photo Ethan Hirsh

It might seem sad, at first glance, that these big greens will bolt this month if we don’t harvest them in time, but in fact, it all works out rather well. The rate of growth of the “cut-and-come-again” leaf greens slows down in December and January, and while we eat the big heads of Tokyo bekana, Maruba santoh, Chinese cabbage, pak choy and the not-tiny tatsoi, we ignore the leaf greens, giving them more time to grow.

Pak Choy in our hoophouse in late December.
Photo Pam Dawling

December 15-February 15 is the slowest growing time for our hoophouse crops.

When the daylight is shorter than 10 hours a day, not much growth happens. The dates depend on your latitude. In Central Virginia, at latitude 38° North, this Persephone period (named by Eliot Coleman) lasts two months, from November 21 to January 21. We have found in practice, that soil temperature also affects the growth rate. And so we have a three week lag in early winter before the soil cools enough to slow growth, and then another 3 week lag  in January before it warms up enough again.

Transplanting spinach from a Speedling flat.
Photo Denny Ray McElya

Cooking Greens to Sow in Central Virginia in January

Outdoors, we sow nothing.

In the greenhouse we tidy up the workspace, “fire up” the germinator fridges (germination chambers made from the carcasses of dead fridges), and prepare our new Seedlings Schedule (see Special Topic for January below)

Around 1/17 we sow some fast early cabbage, such as the OP Early Jersey Wakefield and the hybrid Farao. (We sow lettuce and scallions then too, to keep them company.) At the end of January we sow spinach in Speedling flats if our hoophouse sowings have been insufficient. We have trialed the bare-root spinach against the Speedling spinach and both do equally well.

In the hoophouse, in mid-January we sow Spinach #4, to transplant in gaps in the hoophouse. We usually clear Tatsoi #1 to make space for this. Of the varieties we tried, Reflect does best for this planting, followed by Acadia and Escalade. This winter we have had difficulty buying Acadia and Escalade and are going to try Abundant Bloomsdale alongside Reflect.

Spinach seedlings in our hoophouse for bare-root transplanting.
Photo Pam Dawling

We also sow Spinach #5 for bare-root transplanting outdoors in February or early March under rowcover. This follows the Tokyo bekana or Maruba Santoh as noted above. Reflect and Acadia do well for this purpose, with Escalade close behind. We’ll have to improvise this spring.

In late January (1/24, 1/25), we sow kale and collards for transplanting outdoors in March. I have written before about how well these bare-root transplants work for us, compared to starting these seeds in flats in the greenhouse. It doesn’t work for lettuce at this time of year though – the tiny plants are too fragile and tender.

Vates kale seedlings in our hoophouse for bare-root transplanting outdoors.
Photo Pam Dawling

Follow-on Winter Hoophouse Crops

This is a  sequence of different crops occupying the same space over time. We try to keep the hoophouse fully planted all the time, and one aspect of this is knowing what we are going to sow when we pull an old crop out. Here’s our winter list:

  • 11/17: We follow our 1st radishes with 3rd  scallions
  • 12/23: 1st baby brassica salad mix with 5th radishes
  • 12/31: Some of our 1st spinach with our 2nd  baby lettuce mix
  • 1/15: Our 1st tatsoi with our 4th spinach
  • 1/16: Our Tokyo Bekana with spinach #5 for planting outdoors
  • 1/24: Our pak choy & Chinese cabbage with kale & collards for outdoors
  • 2/1: Our 2nd radishes with our 2nd baby brassica salad mix
  • 2/1: Our 1st Yukina Savoy with our 3rd mizuna/frilly mustards
  • 2/1: Some of our 1st turnips with our 3rd baby lettuce mix
  • 2/1: More of our 1st spinach with dwarf snap peas

Cooking Greens to Transplant in Central Virginia in January

Outdoors, we transplant nothing.

In the hoophouse, we fill gaps that occur in the beds. We replace spinach with spinach, brassicas with brassicas wherever possible. We use the Filler Greens which were sown October 10 and October 20 (brassicas such as senposai, Yukina savoy and the frilly mustards) and October 24 and November 9 (spinach). In December I mistakenly said that December 25 is our official last date for using the brassica fillers because there is not enough time for them to make worthwhile growth before they bolt. But I really meant January 25! Sorry!

  • Until January 25, fill gaps with Asian greens, spinach or lettuces as appropriate to match their neighbors.
  • From January 25 to February 20 fill all gaps everywhere with spinach transplants, except for places that will be sown in new crops in February.
  • From February 20, only fill gaps on the outer thirds of the beds, leaving the bed centers free for tomatoes, etc. in mid-March.

Other Cooking Greens Tasks in Central Virginia in January

We continue to harvest the hardier greens, and if (when) low temperatures are forecast, we might decide to clear the vulnerable crops and put them in the cooler.

See Cooking Greens for November for more details on winter-kill temperatures

During December we had two nights at 17°F (-8.5°C). The Koji are looking quite damaged. We grew more of this than we could eat before temperatures got too cold. Next year I hope for a return to the more cold-tolerant Yukina Savoy instead. We have not covered the spinach, because of issues with rowcover fibers getting in the food, and we’ll see how much production we get without rowcover. I’m expecting it to be a lot less, as spinach (like kale and lettuce) makes some growth whenever the temperature is 40°F (4.5°C) or more. That happens much more often under rowcover on sunny days than in the open. Savoyed spinach which we prefer) is hardier than smooth-leafed varieties. 10°F (-12°C) could kill the larger leaves and 5°F (-15°C) could kill it off entirely. This would be unfortunate as we expect to harvest a lot from out over-wintered spinach in the spring. Maybe temperatures won’t get that cold this winter, but I’m not holding my breath. Some spinach (Bloomsdale Long Standing, Bloomsdale Savoy, Olympia) is hardy down to 0°F (-18°C). We, however, have not been focused on growing the variety with the best absolute cold-tolerance.

Our chard is pretty much dead. The green is hardier than the multi-colored, which died a while back. Green chard is hardy to 12°F (-11°C), but ours is already weather-beaten. Because we have nice chard in the hoophouse, we no longer try to preserve the outdoor crop in winter.

I’m expecting January temperatures to bring the outdoor Koji and senposai to an end.

Spotting cabbage seedlings from a seed flat into a transplant flat.
Photo Wren Vile

Special Cooking Greens Topic for January: Lots of Planning!

We get our Crop Review, Seed Inventory and Seed Orders out of the way before the end of the year, then dive in during January to line everything else up for the next growing year. We use a lot of spreadsheets, and also maps and lists. First we prepare our new Seedlings Schedule, then our complex Fall Brassica Spreadsheet and Map, Field Planting Schedule, Hoophouse Schedule for March to September crops (those are not cooking greens!), and then our Raised Bed Plan and our monthly Garden Calendar.

The Seedlings Schedule Spreadsheet is most pressing, as we start greenhouse sowings in mid-January. Updating the spreadsheet from last year’s to create the new spreadsheet takes us three hours, plus proofreading and corrections. As we go, we make a list of questions or points to fix later, and we use highlighter on cells with unsure data to go back to. Our seedlings schedule has a column for the planned sowing date, one to write in when we actually do that sowing (in case it’s different), columns for the germination date, and the hoped-for transplant date, the vegetable, variety, how many row feet we want to plant, how many plants we will transplant in 100ft, and then a column with a calculation of how many plants we want to grow (allowing 20% extra on most crops). We will be spotting our transplants into flats of 40 plants, so next we calculate how many spotted flats we will need (simply the number of plants divided by 40). From that we calculate how many seed flats to sow. We reckon on getting 6 spotted flats from one seed flat, so again it’s a simple division. And we round up.

For crops that we sow in cell-packs (plug flats) we add another 20% to the Plants number. Lots of things can go wrong in January and February and we want to be sure to have enough plants. Also a lot of these early cell-packs are tomatoes for the hoophouse and we might want 15 different varieties.

All our spreadsheets have a Notes column, either with a pre-recorded reminder or hint, or with space to write in anything unusual or a different idea for next year. We check this and revise the sowing and transplanting dates accordingly.

Once we have the new spreadsheet set up, we get ready for the slow part of the job. One nice thing about spreadsheets is that you can sort the data each time you want a different perspective. We want to end up with a schedule in date order, but as far as feeding in the crop data, an alphabetical list by crop is much easier.

First we go through the current year’s Seed Order updating Varieties and Row Feet. Then we go through the Seed Order line by line, cross-checking to ensure that everything ordered gets sown (crops for transplanting only).

When we’re satisfied with that, we resort the data by transplant date, then by Vegetable, then Variety. We take the previous year’s Outdoor Planting Schedule (Field Planting Schedule) and revise the Seedlings Schedule accordingly.

Before we’re done, we check the highlighted cells and resolve any unresolved issues on our piece of paper. We check germinator shelves in use on any one day: We have space for 24 flats at once. Check the number of Speedlings in use at one time, we have 27. We refer to last year’s Seedlings Schedule for days to germination.

With all that work done, we can resort the data by Sowing date, then by Vegetable, then Variety. We proofread for sense before tidying up the formatting, and making sure all the columns fit on one sheet. We revise the instructions before we forget!

Cooking Greens in December

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

Cooking Greens to Harvest in Central Virginia in December

In December there’s chard, collards, kale, komatsuna, senposai, , spinach, tatsoi, and Yukina savoy, Eat-All Greens from the outdoor garden and also stored cabbage. The most cold-hardy greens start to come into their own.

From the hoophouse we continue harvesting chard, kale, senposai, spinach, tat soi thinnings or leaves, Tokyo bekana/Maruba santoh leaves (if we have not yet harvested whole plants because we saw signs of bolting), turnip greens, Yukina Savoy.

From late December we keep a close eye on the Chinese cabbage and pak choy, for signs of bolting. Normally these will bolt in January, so we harvest the whole plants that month. But we have sometimes needed to harvest the plants before we get to January.

Cooking Greens to Sow in Central Virginia in December

Outdoors, we sow nothing

Brassica (mustard) salad mix in our hoophouse in late November.
Photo Pam Dawling

In the hoophouse, on December 18 we sow brassica salad #2. Sometimes called mustard mixes, these are mixed brassicas to cut like baby lettuce mix when they are still small. Often we make our own mix at this time of year, using leftover seeds that we don’t want to keep for next year. We are busy working on our seed inventory and seed orders, so it gives us a use for odds and ends of packets. Just avoid bristly-leaved radishes and turnips! Using random seeds works for us because we do not expect yield-miracles. We will not get a lot of cuts from these plants before they bolt in March or early April. Our first round of Brassica Salad Mix is sown October 2 and is harvested several times between October 29 and December 21. Much faster growth in October and November than in December and January! We make a third sowing on New Year’s Day.

Cooking Greens to Transplant in Central Virginia in December

Outdoors, we transplant nothing

In the hoophouse, we transplant spinach, senposai, Yukina Savoy, Frills (frilly mustards) to fill gaps that occur in the beds. We replace spinach with spinach, brassicas with brassicas wherever possible, filling gaps caused by either harvesting whole plants or Bad Things (those are usually fungal diseases).

Our Filler Greens are sown October 10 and October 20 (brassicas) and October 24 and November 9 (spinach). JANUARY 25 (I originally mistakenly said December 25) is our official last date for using the brassica fillers because there is not enough time for them to make worthwhile growth before they bolt. After that date we fill all gaps with spinach plants.

Short rows of filler greens, lettuce and spinach in the north edge bed of our hoophouse in December.
Photo Kathleen Slattery

Other Cooking Greens Tasks in Central Virginia in December

While watching the temperature forecasts, we continue to harvest the hardier greens, such as chard, yukina savoy, collards, kale, spinach and tatsoi. If low temperatures are forecast we might add rowcover to some of the beds, or decide to clear the vulnerable crops and put them in the cooler.

See Cooking Greens for November for more details on winter-kill temperatures

This winter we have already had 16°F (-9°C) and 18°F (-8°C) in mid-November. As temperatures drop, we clear these crops before their winter-kill temperatures happen:

15°F (–9.5°C): kohlrabi, komatsuna, some cabbage, red chard (green chard is hardy to 12°F (-11°C)), Russian kales, rutabagas if not covered, turnip leaves, most covered turnips.

12°F (-11°C): Some beets (Cylindra,), some broccoli, Brussels sprouts, some cabbage (January King, Savoy types), most collards, senposai, some turnips (Purple Top).

10°F (-12°C): Covered beets, Purple Sprouting broccoli for spring harvest (too cold in central Virginia for us to grow that), a few cabbages (Deadon), chard (green chard is hardier than multi-colored types), some collards (Morris Heading can survive at least one night at 10°F/-12°C), probably Komatsuna; Senposai leaves (the core of the plant may survive 8°F/-13°C), large leaves of savoyed spinach (more hardy than smooth-leafed varieties), Tatsoi, Yukina Savoy.

5°F (-15°C): some collards, some kale (Winterbor, Westland Winter), smaller leaves of savoyed spinach and broad leaf sorrel. Some tatsoi. Many of the Even’ Star Ice Bred greens varieties are hardy down to 6°F (-14°C).

0°F (-18°C): some collards (Blue Max, Winner), Even’ Star Ice-Bred Smooth Leaf kale, some spinach (Bloomsdale Long Standing, Bloomsdale Savoy, Olympia). Vates kale survives.

Vates kale outdoors. An oleracea type, Vates is very cold-hardy.
Photo by Nina Gentle
Russian kale (napus type) gives us good yields in our hoophouse in January.
Photo Pam Dawling

Special Cooking Greens Topic for December: Understanding kale types

Russian and other Russo-Siberian kales (napus varieties) do better in the hoophouse than Vates blue curled Scotch (and other European oleracea varieties). Napus kales will make more growth at lower temperatures than oleracea kales, although they are not as cold-tolerant. “Spring” kales (napus) will persist longer into warmer weather than Vates (oleracea) can, from a spring sowing. The vernalization requirement for napus kales with about eight leaves is 10–12 weeks at temperatures below 40°F (4°C). Brassica oleraceae kales will start flowering after 10–12 weeks below the relatively balmy spring temperature of 50°F (10°C).

Special Cooking Greens Topic for December: Ordering Seeds (Adapted from Sustainable Market Farming)

Every year we try to introduce a new crop or two, on a small scale, to see if we can add it to our “portfolio.” Some-times we can successfully grow a crop that is said not to thrive in our climate.(Brussels sprouts really don’t). We like to find the varieties of each crop that do best for our conditions. We read catalog descriptions carefully and try varieties that offer the flavor, productivity and disease resistance we need. Later we check how the new varieties do compared with our old varieties. We use heirloom varieties if they do well, hybrids if they are what works best for us. We don’t use treated seeds or GMOs, because of the wide damage we believe they do.

Calculating the seed order

When we figure out how much seed to order we add in some extra for some things – crops that can be difficult to germinate, or we really don’t want to cut too close. We add 20 percent extra for most crops, but only 5 percent for kale, 10 percent for onions and collards and 30 percent for melons. These numbers are based on our experience – yours might be different. We also know which seed we can buy in bulk and use over several years. This gives us an additional security against poor germination, or plagues of grasshoppers or caterpillars. For me, a big bag of broccoli seed for each of our main varieties gives some kind of warm glow of horticultural security!

This is the time of year we adjust the “seed rate” (seed/100′ or /30 m) column of our spreadsheet using information from our past year, and we feed in the next year’s crop plan for varieties and succession plantings – everything we have decided so far about next year. We make notes about any problems or questions we need to resolve later, and we’re sure to order enough seeds to cover these eventualities. We have found it worthwhile to proofread our inventory and order form carefully before making our final decisions, as mistakes not discovered until planting day can be a big problem.

Sowing Rainbow Chard. in the greenhouse
Photo Pam Dawling

Formatting and placing seed orders

On the Seed Order version of our spreadsheet, we include columns for the name of the supplier we buy each variety from (we just use the initial), the item number in the catalog, the packet size and the price. (Be careful though, if you carry this information over from year to year – prices change.) Once we have composed our total seed order, we sort the orders by the name of the supplier. Then we can calculate the total price for each supplier. This also gives us the opportunity to look at price breaks for large orders and move an item from one supplier to another, if that makes sense. At this point we usually make a cup of tea and reward ourselves with an “impulse buy” or two, if that doesn’t push us up into a higher shipping cost bracket or blow the budget. We place our orders online these days, nice and early, to increase the chances of getting exactly what we want.