Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

Our pond iced over.
Photo Ezra Freeman

Winter-Kill Temperatures of Cold-Hardy Vegetables 2021

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

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

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

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

New Info this winter

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

My results from other years still hold up.

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

Using the List

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

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

Outdoor killing temperatures of crops (unprotected unless stated)

35°F (2°C):  Basil.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Hoophouse Notes

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

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

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

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

Lettuce Notes

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

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

Notes on Chicories and Endives

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

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

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

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

© Pam Dawling 2021


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

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

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

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

My previous contribution is an 8-part Garden Planning Course

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

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

 

Root Crops in April – the Hungry Gap

Young Cylindra beets in early May.
Photo Pam Dawling

Root Crops to Plant in Central Virginia in April

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

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

Here we can plant potatoes anytime in April.

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

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

Root Crops to Harvest in Central Virginia in April

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

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

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

Colorado Potato beetle late stage larva
Photo Pam Dawling

Other Root Crop Tasks in Central Virginia in April

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

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

What is the Hungry Gap?

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

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

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

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

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

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

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

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

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

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

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

Read more about the Hungry Gap

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

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

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

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

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

Root Crops in May

Root Crops in June

Root Crops in July

Root Crops in August

Root Crops in September

Root Crops in October

Root Crops in November

Root Crops in December

Root Crops in January

Root Crops in February

Root Crops in March

Workhorse Crops for the Month

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

 

Cuban Agroecology: FANJ and La Felicidad Permaculture Garden

The library at the Foundation for Nature and Humanity (FANJ), Havana, Cuba
Photo Alan Ismach

Monday January 13 (Havana)

This was Day 7 of my January 2020 Agroecology trip with Organic Growers School. This day we studied ecology, climate change, the effects of extractive agriculture, deforestation, reforestation and responses including Bioreserves and urban permaculture gardens.

To read other posts in this series, click the Cuban Agriculture category. Click this link to see a short video about the OGS Cuba Agroecology Tour. It goes live on April 14.

FANJ (Antonio Núñez Jiménez Foundation for Nature and Humanity) Havana

After breakfast at our casa, we rode our tour bus to FANJ (Antonio Núñez Jiménez Foundation for Nature and Humanity), a non-governmental cultural and scientific institution, dedicated to the research and promotion of environmental protection in relation to culture and society. We were given a tour of the museum and library. Roberto Pérez Rivero, the PNS-FANJ Director, gave us a talk “Cuban Environment, the challenge of climate change and development: an environmental education approach.” It covered science, urban agriculture and food security in Cuba.

Cabinets of artifacts at the FANJ, Havana, Cuba. Photo by Pam Dawling

We sat in the library around the glass topped tables of artifacts.  National treasures and plastic lawn chairs!

There are 11 million Cubans, the population is not growing. The island of Cuba is only 30 miles wide at the thinnest point, and so the country is heavily influenced by the ocean. There are three or four ecosystems: sand beaches, mangrove swamps, bush (shrubs) and trees, seagrasses [maybe seaweeds?].

The canoe from the expedition by FANJ.
Photo Pam Dawling
Log canoe in use by the expedition.
Map of the route of the FANJ canoe from the Amazon to Cuba.
Photo Pam Dawling

Biologically speaking, Roberto Pérez Rivero says the Caribbean is a province of the Amazonian Rainforest. A big project associated with FANJ was a journey in a large hollowed tree canoe, from the Amazon to Cuba. I didn’t understand everything. We saw the canoe and some photos and various artifacts from that trip.

Photo of the expedition in the canoe Simon Bolivar.

In the eighteenth century, ship-building was important in Cuba. There was a “Forbidden Forest” reserved for shipbuilding. In 1769, the Santisima  Trinidad was built in Havana, and was possibly the largest warship in the world at that time. It fought on the Spanish and French side against Britain in the US War of Independence.

No gold was found in Cuba, so the colonizers made plantations of several crops. Two species of tobacco, Rustica and Virginia were hybridized. Haiti had been the main coffee producer in the region, up to that point. Sugar cane came later on, from New Guinea, in the time of Columbus.

The Toxic Acids of Cuba: Rum, Tobacco, Coffee and Sugar.

Model of a rum factory in the Havana Rum Museum, Cuba.
Photo Pam Dawling

There used to be three enslaved people (they say “slaves”) per white person. The plantation system shaped the environment. 90% of the land had been forests of all kinds. There were edible rats (vegetarian) living in the tree canopy, but no monkeys. By 1816 there was deforestation around the cities, but still 87% coverage overall.  In 1909 there was only 54% tree cover left; in 1959 it was down to only 14%. The Cuban people (not the IMF!) worked on reforestation. In 2018 there was 32% tree cover (going up!)

There are 26 types of forest in Cuba, a “miniature continent”, including 4 areas of pines. This is the southern limit (20°N) for pines, which don’t grow in tropical areas [such as Jamaica, as I’d noticed on my trip there.] There are 40 million arable acres. Article 27 of the Constitution of the Republic of Cuba, 1996 revision, lists environmental problems:

  • Land degradation (heavy Soviet tractors, mono cropping).
  • Bauxite versus forest.
  • Contamination (pollution). During the Special Period businesses collapsed and pollution decreased; waste was converted into resources.
  • Loss of biodiversity, although this was less bad in Cuba than in other Caribbean countries; there are 240 protected areas.
  • Lack of water: in the dry season, water is needed for agriculture; more CO2 means more humidity (more water is trapped in the air).
  • Impacts of climate change; amphibians are being strongly affected. It’s better to protect ecosystems than individual species.

Bioreserves of the Biosphere: There are six Natural Areas designated as Reserves. Fishing is illegal if from a Styrofoam raft. [? I cannot explain this part of my notes!] Another speaker told us there is no fishing industry in Cuba – fish is imported.

Cuba reduces the threat of climate change by making preparations. They have 72 hours to prepare before each hurricane, thanks to Russian radar. The mangroves act as a “Live Task Force”and block storm surges.

“Dinosaurs did not go extinct, they evolved into birds” Birds can fly away. Roberto Pérez Rivero is an Informed Optimist. The Apocalyptic Vision doesn’t serve us.

More Information

There are many videos of permaculture talks by Roberto Pérez Rivero in the period 2006-2017.

2000: The Antonio Núñez Jiménez Foundation and Urban Agriculture  Urban Agriculture Notes, Published by City Farmer, Canada’s Office of Urban Agriculture

2006: The World Wildlife Fund, In its 2006 Sustainability Index Report, using a combination of the United Nations Human Development Index (a measure of how well a nation is meeting its nutrition, water, health care, and education needs, etc.) and the Ecological Footprint (natural resource use per capita), determined that there is only one nation in the world that is currently living sustainably — and that nation is Cuba. The Report states, “No [other] region, nor the world as a whole, met both criteria for sustainable development.”
2007: View the 53 minute Cuban Permaculture documentary, The Power of Community: How Cuba Survived Peak Oil...Cubans share how they transitioned from a highly mechanized, industrial agricultural system to one using organic methods of farming and local, urban gardens after they lost global support in the early 1990’s. Roberto Pérez, a well-known exponent of this Cuban approach to ecology, can be seen in this documentary.
2008:BBC programme on Cuba’s permaculture gardening

The BBC’s Around the World in 80 Gardens (2008) (viewable only in the UK) introduces the urban organic food gardening revolution in Havana, Cuba.

2008:Click HERE for a three-part talk by Cuban permaculturist Roberto Pérez that delves deeper into Cuba’s green revolution, and a half-hour video Peak Moment: Learning from Cuba’s Response to Peak Oil

A BBC2 program write-up.
2011: Roberto Pérez spoke at the Climate Change | Social Change conference, April 11-13, Sydney.  `Climate change means we must change’
Our Changing Climate environmental video essay

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Entrance to the La Felicidad Permaculture Garden associated with FANJ
Photo Pam Dawling

La Felicidad,  a small-scale permaculture garden, an education and urban agriculture center associated with FANJ

The entrance to La Felicidad Permaculture Garden, Havana, Cuba
Photo by Alan Ismach
Jésus Sanchez with tour guide Josetti translating, telling us about the permaculture garden La Felicidad.
Photo Pam Dawling

A lively 73 year old farmer, Jésus Sanchez, runs a permaculture backyard garden as an educational center, with training from FANJ.

Composting toilet at La Felicidad Permaculture Garden, Havana, Cuba
Photo by Alan Ismach

They have some small caged livestock, a composting toilet, vegetable beds following the Permaculture Guilds system, a shaded outdoor classroom, lots of explanatory posters and a model of the garden.

Map of La Felicidad Permaculture Garden, Havana, Cuba. Photo Pam Dawling

I was surprised to see the vegetable beds edged with upside-down glass bottles! [We have a “no-glass in the gardens” rule at twin Oaks, to avoid cuts.]

Permaculture raised beds edged with glass bottles. La Felicidad, Havana, Cuba
Photo by Alan Ismach

They had some plants growing on their house roof, where a few people at a time could view them. or get an overview of the garden.

Overview of La Felicidad permaculture garden from the house roof.
Photo Alan Ismach

See Learning About Permaculture at La Felicidad in Cuba, one of the Franny Travels to Cuba YouTube channel offerings. Franny was part of our January 2020 tour group.

Lunch on our own: I don’t remember what or where I ate. Or what I did in the afternoon. I probably ate my leftover pizza at the casa. I might have done some emailing. I’m surprised I didn’t write anything down. It’s hard to imagine I frittered away a whole afternoon of this special time! But I do remember dinner at the Garden of Miracles (Jardin de los Milagros Paladar) farm-to-table restaurant, with a guest speaker, Rafael Betancourt. I’ll tell you about that and their rooftop garden, another time.

 

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.

 

Root Crops in March

We shovel many wheelbarrows full of compost to our raised beds every year.
Photo Wren Vile

Root Crops to Plant in Central Virginia in March

As soon as the soil is dry enough and not frozen, we spread compost on the raised beds we plan to plant in February and March, and till in the compost. We make ourselves a Spring Start-up Plan, so we know where to focus our energy when the weather gives us a chance.

Spring Start-up Plan

We aim to spread compost 4-6 weeks before planting, rototill 2-4 weeks before planting, and prep the bed a week or two before. This is more time than we allow later in the year, but in early spring it’s good to seize the opportunities that arise and not take the weather for granted.

This means in January we compost and till beds for spinach, turnips and our first carrots. In the first half of February we till the turnip beds and any beds of winter-killed oats cover crops that we will be planting soon. We compost the first lettuce bed, the kale and collard beds, and those for cabbage, beets, more carrots, senposai and peas (all have planting dates March 9 to 15). In the second half of February, we compost the third carrot bed and till the ones we already composted. In early March we till the third carrot bed.

A bed ready for tilling after mowing the cover crop and spreading compost.
Photo Pam Dawling

Once we get to March, day length has increased and temperatures are starting to climb. There is a noticeable increase in the rate of germination and growth (unlike for our February sowings, which are rooted in faith and optimism!) All being well with the weather (it’s extremely wet this year!), in early March, we direct sow turnips (3/6- 3/16), and radishes #1 (Cherry Belle or some other fast variety)

In mid-March, we can transplant kohlrabi. And we direct sow carrots #3 and beets. See below for more about beets. In late March, we direct sow our carrots #4, and more radishes and beets. We can sow kohlrabi if we have no transplants, and thin to 6” (15 cm) later.

Potatoes

A row of potato seed pieces ready to cover.
Photo by Wren Vile

We plant potatoes when the daffodils bloom, usually mid-March. Last year I wrote an extensive series of posts about growing potatoes.

See Planning to Grow Potatoes Again, the last part of a monthly series on growing potatoes, a dietary staple.

PART ONE: Planting potatoes (April)

PART TWO: Growing potatoes (May)

PART THREE: Potato pests and diseases (June)

PART FOUR: Harvesting potatoes (July)

PART FIVE: Storing potatoes (August)

PART SIX: Planning to grow potatoes again (September)

Beets

Detroit Dark Red beets in early June sunshine.
Photo Pam Dawling

Beets are workhorse root crops that thrive in mild weather, store well, and are popular traditional foods. They are crops that can provide high yields for the time invested.

Beets come in several types, round, top-shaped and long. The size and quality of the greens is a factor if you sell bunched beets with tops, or use the tops for greens. We like the 6” (15cm) long Cylindra/Formanova/Forono ones (55 days to maturity, OP). They are very tender and easy to cut into regular slices, for pickles or cooking. The skins come off easily, and the flavor is very sweet and the texture tender.

Among round ones we like Ace (50 days to maturity, F1 hybrid), and Detroit Dark Red (60d), a tender open-pollinated variety. Detroit Crimson Globe is said to maintain better flavor in hot weather than most others, which can develop off-flavors. Early Wonder Tall Top (48d), is also open-pollinated. Lutz Green Leaf (70d) is a big long-storage variety. There are also golden beets, white beets and candy-striped Chioggia beets, although in my experience, what they gain in appearance they lose in flavor and tenderness.

Beets seeds average 35,000 /lb. 2,200/oz, 80 seeds/gm. 1,285 seeds (2/3 oz, 18gm) sow 100’ (30m).  150’/oz, 2,300’/lb., 9 lbs/acre. 315,000 seeds/acre. Yield can be 40 lbs. (18kg) greens, 100 lbs. (45kg) roots/100’ (30m), or 14,000 lbs/acre, 2540 kg/ha.

Beets need a pH of 6.0-7.0, preferring 6.5-6.8.  They require abundant potassium, which can be supplied by woodash. Boron deficiency can show up in beets as internal browning, or dark dead tissue, as well as distorted leaf growth. It is most likely to occur in alkaline soils after long hot, dry spells. Beets can suffer from “zoning,” (white rings in the roots), if there are acute weather fluctuations.

Young Cylindra beets in early May.
Photo Pam Dawling

Sow beets whenever the soil is between 50°F (10°C) and 95°F (35°C), so long as you can keep the surface damp. With beets we do a single sowing in mid-March and more in early August. We are growing for fresh use, pickling and storage, but not bunch sales, so we don’t need to do frequent sowings. For a continuous supply of greens and baby beets, sow every 2 weeks from spring until 8 weeks before regular frosts usually occur, or about 10 weeks before a heavy freeze is expected.

We direct sow either dry beet seed, or some we have presoaked for 1-2 hours. Beet seed drowns easily: don’t use too much water or soak for too long.  Sow 0.5″(1.2cm) deep in spring, deeper in hot summers, but never more than an inch (2.5cm) deep. We sow an inch (2.5 cm) apart in single rows 8-10” (20-25cm) apart. Others sow in bands 2-4″ (5-10cm) wide, at about 15 seeds/ft (2cm apart), with bands 12-18″ (30-45cm) apart. As for carrots, avoid soil crusting.

It is important to get good soil contact for the corky seedballs, so tamp or roll the rows after seeding. Keep the rows damp, by watering as needed for the 5-17 days they take to emerge. Beet seeds are actually seed balls (clusters of seeds) so each one you plant will produce several seedlings right next to each other. “Singling” the beets is an important step, and they will benefit from hoeing, thinning and weeding. Beets deal with weed pressure and crowding a lot better than carrots do, so if you have to choose which to weed, the carrots win! We thin in stages, so that at the second thinning, the baby beets can be used as a crop.

Detroit Dark Red beets , harvested, washed and trimmed.
Photo Pam Dawling

For mature beets, allow each a minimum of 3” (7.5cm). The Cylindra beets can be left a bit closer, and will push themselves up out of the soil as they grow. Know and Grow Vegetables recommends establishing 5 plants per square foot (54 per square metre) for early beets. This translates to a final spacing of 4 x 7” (10 x 18cm). For maincrop beets, aim for 10-15 per square foot (107-161 per square metre.) For maximum total yields of small sized roots use a spacing of 1 x 12” (2.5 x 30cm).

This info about growing beets is excerpted from my book Sustainable Market Farming. See the book for more on pests and diseases, harvesting and storing, and seed saving.

In our climate, beets are one of the crops that can be sown in spring and again in early fall (actually August for beets here in central Virginia). See my August post Sowing beets, radishes and kale, transplanting cabbage.

See Root Crops in August for more about fall beets. Beets can be tricky to germinate in hot weather, but to get good storable-sized roots, we need to get them established by 8/20. (Two months before our average first frost.)

Root Crops to Harvest in Central Virginia in March

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

As in January and February in central Virginia, there are no roots to harvest outdoors in March except parsnips, Jerusalem artichokes and horseradish. We do have horseradish, but not the others, but we don’t have a lot of demand for that.

We have had outdoor night temperatures of 12°F/-11°C and 11°F/-13°C. This winter we had some carrots outdoors over the winter. We harvested them and got 150 pounds from 400 row feet. Not a high yield but they do taste good! They are Danvers 126. The intended sowing date was August 14, but we didn’t get the seed in the ground until September 5.

A crate of overwintered Danvers 126 carrots

In the hoophouse our #4 radishes will get harvested during March. Our #5 radishes, sown 12/23, will then feed us until around April 7.

We still have some of our good size second hoophouse turnips until mid-March. We sowed those on October 25. The greens are a bit ragged now and less appetizing for cooking, although on cold rainy days, they make for more pleasant harvesting than any greens outdoors! Turnip greens (and Russian kale) are our last hoophouse greens to bolt, so we value them.  We need to harvest the turnips to make space to transplant our hoophouse tomatoes in mid-March.

Other Root Crop Tasks in Central Virginia in March

  • Green chit (pre-sprout) seed potatoes, see Planting potatoes .
  • Buy seed potatoes for June planting, and refrigerate them. Keep at 40-50°F (4.5-10°C) in the dark, until 6/1.
  •  Test and condition sweet potatoes for 2 to 4 weeks at 75-85°F (24-29°C), 95% humidity if you are planning to grow your own sweet potato slips.
Sweet potato sprouting slips.
Photo Pam Dawling

Special Root Crop Topic for March in Central Virginia: What makes vegetable crops bolt?

Green mizuna bolting in our hoophouse in mid April. Although the mizuna is bolting, the Scarlet Frills is hanging in there.
Photo Pam Dawling
  • Bolting is the term for plants going to seed. Rather than grow more leaves and bigger roots, the plants develop stems, skinnier and fewer leaves, then flower buds, flowers and seeds.
  •  The plants are switching their energy to survival of the species in the face of unsuitable 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. Lettuce 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.
  •  Crops inclined to bolt include arugula, basil, beets, brassicas (such as cabbage), carrots, celery, leeks, lettuce, onions, turnips and spinach.
  •  Bolting is initiated by plant hormones called gibberellins.
  •  Although bolting is usually seen on crops approaching maturity, it is initiated much earlier.
  •  It’s a complex business, understanding the various triggers to bolting.
  •  Stress factors, including changes in day length (usually an increase), high temperatures or low temperatures at particular stages in a plant’s growth cycle, plant size, plant type, root stress, and stresses such as insufficient water or minerals.
  • Increased day length: Bolting can happen when day length increases as summer approaches. This can be a problem if you planted your seeds too late in the spring. The extra hours of light trigger annual plants to run to seed.
  •  High soil temperatures: As soil temperatures increase in summer, 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.
  • 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:
  •  Annual plants 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. When an annual plant bolts, it’s the beginning of the end.
  • Biennial plants (onions, leeks, carrots, beets, and chard) grow big the first year, then seed the second year. They can initiate flowers in the first yea, due to unsettled weather early in the season. Bolting usually occurs after a prolonged cold spell, often during an immature stage. Cold nights, hot days and late frosts may also contribute to premature flowering.
  • 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.
  • 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 fights against you.

Collards bolting in late March.
Photo Pam Dawling

Next week I will provide information on avoiding, preventing and postponing bolting.

Cuban Agriculture, French coffee plantation Cafetal Buenavista

Coffee bean drying beds at Cafetal Buenavista, Artemisa, Cuba.
Photo Pam Dawling

Cuban Agriculture, Tour of a restored historic early 19th century French coffee plantation (Cafetal) Buenavista, worked by 100 enslaved Africans, Las Terrazas Ecovillage, Artemisa.

This is an episode in the tales of my Agroecology Tour of Cuba in January 2020 with the Organic Growers School. Click the category Cuban Agriculture to see more posts in the series. In particular, refer to my most recent post on Las Terrazas. The Cafetal Buenavista is on the land of that ecovillage and bioreserve.

The master’s house at Cafetal Buenavista coffee plantation, now used as a restaurant.
Photo Pam Dawling

Buenavista is Cuba’s oldest coffee plantation, built in 1801 by French refugees from Haiti. The attic of the master’s house (which is now a restaurant) was used to store the beans until they could be carried down to the port of Mariel by mule.

Cafetal Buenavista plantation final drying floor and sheds.
Photo Pam Dawling

The coffee beans were sun-dried on huge drying beds during the day (top photo), then piled up every night in the center of the drying bed, and covered. If it rained, the beans were bagged up and stored in small low sheds, shown above.

The mill building at Cafetal Buenavista plantation.
Photo Pam Dawling
The coffee mill inside the thatched building at Cafetal Buenavista.
Photo Pam Dawling

The huge tajona (grindstone) that cracked the coffee beans is well restored and does move!

The coffee bean mill at Cafetal Buenavista plantation.
Photo Pam Dawling

Ruins of the quarters of some of the enslaved people held there can be seen alongside the drying beds. They were chained up at night in tiny 8-12 person stone cells built onto the walls of the coffee drying beds.

Cafetal Buenavista plantation. Cells where enslaved coffee workers were shackled at night.
Photo Pam Dawling

We had a talk about slavery with our Cuban tour guide Josetti. A study of the DNA of 2000 Cubans showed widespread genes from indigenous people, Africans, Chinese, Spanish and other Europeans. It’s impossible to tell ancestry from skin color. General guide: “Our mothers were Africans, our fathers European.” There is still individual racism, but it is not institutionalized as it is in the US, Josetti thinks. Slavery was abolished in Cuba in 1865, earlier than in Brazil, for example.

Photo Pam Dawling

The view from the top of the plantation is breathtaking!

For more, see and listen to:

Insight Cuba blog post on Las Terrazas

http://www.touristinyourtownpodcast.com/tag/buenavista-coffee-plantation/ Podcast

Shade-grown slavery

Slavery and Spatial Dialectics on Cuban Coffee Plantations, Theresa A. Singleton

I got a tick bite (was it one of the sterile ones Cuba has introduced to defeat tick-borne diseases? I didn’t get sick, so I don’t know that it wasn’t)

We got back on the bus to return to Havana for our last 3 days. Everyone wanted to stay in beautiful Viñales. We have a farm work project on Monday and a free day Wednesday (we might go to the beach). We returned to Havana, registered at our casas. I went with four others of the group to a small corner café, and spent 3 CUC on pizza and 2 CUC on a beer. The pizza was so big I still had leftovers to take home after I gave one piece away.1 CUC=$1 US.

 

Book Review: The Comic Book Guide to Growing Food

Book Review: The Comic Book Guide to Growing Food: Step-by-Step Vegetable Gardening for Everyone

Joseph Tychonievich and Liz Anna Kozik, Ten Speed Press, 2021. 90 pages, color throughout, $19.99 paperback, $12.99 Kindle.

This is the first time I’ve reviewed a comic book, and it makes a refreshing change from my usual (less comic) gardening and farming reading. This small book, with text by Joseph Tychonievich and drawings by Liz Anna Kozik, is a delight. The art is wonderfully clear and realistic, even though they are not botanical drawings. The page of seven herbs makes them all distinguishable. The characters have character, keeping the reader engaged with the plot (oh, not a deliberate pun!)

This will be a great book for new gardeners (of whom there are acres, as a result of Covid-19). It will also particularly help recovering failed gardeners get a fresh, more successful start. It is perfect for visual learners, gardeners with English not their first language, and young gardeners. I have a gardening friend who says her teenager reads only graphic novels and she hopes this book will lead him to do more gardening, more enthusiastically!

It is easy to read/look at, entertaining and accurate (therefore helpful). The breezy, friendly conversations between the fictional characters, young novice gardener Mia (who writes code as a day job) and retired neighbor George, show a great example of food-growing (and computer help) as mutual aid. Gardening as a step to a more peaceful and productive future.

The book covers location, choosing crops, timing, soil testing, bed prep, buying plants, starting seeds, planting in the garden or in containers, and maintenance. This is followed by troubleshooting, harvesting, celebrating, and a “Cheat sheet of cheat sheets” and further reading. The cheat sheets throughout step us aside from the story to dive into some aspect more deeply. Come back to those when you need them.

Mia is savvy about technology, finding a compass app or a last frost date when she needs it. George has the gardening experience to share, including his ever-changing Rule #1! (Grow what you like to eat. Grow what’s easy to grow. Always grow herbs. Grow flowers. Get a soil test.)

Important points are included, such as even though organic fertilizer is best, using too much is a bad thing. Check for lead in city soils and if you find it, garden elsewhere (community garden?), grow vegetables in containers of bought-in soil, or grow flowers, not food. Why is Swiss chard easier to grow than spinach? Do you actually like radishes?

Packed in this little book, you will find how to build raised beds, how to mulch, how to choose healthy plants to buy, which crops do better from seed, the most important bugs to watch out for and more. Joseph the writer has been gardening most of his life, and Liz Anna the artist clearly knows her vegetables too.

Pages from the Comic Book Guide to Growing Food. Art by Liz Anna Kozic. Text by Joseph Tychonievich

What is missing that I would have included? Making compost (can be an issue in city gardens, I know); more about choosing seed varieties in stores, catalogs or online; sowing seeds (like carrots) in rows rather than individual holes.

What is included that I would not have thought of? Root-pruning bought plants to encourage good outward growth. A flow chart of whether or not to water that day. Ideas for garden party snacks! The value of a smartphone as a gardening tool!

This is a real book – it has an index! (Some of my readers may know I live with people who index books, and the index is a better way to judge a book than the cover!)

Yes, this book works as a guide for new vegetable gardeners, and right now when you can’t garden with your neighbor physically at your side, this could be the next best thing. It packs a lot in a small space, which is probably what most of the readers are also hoping to do in their gardens!

For sure, the topics are simplified, but the most important bits are all there, including plenty of cautions to help prevent common mistakes, and make it more likely that readers will continue to garden and learn in the future. There are a few resources listed at the end, useful pointers of where to turn when this book can’t get into enough details, or you’ve found a bug that the authors don’t include. This book and a smartphone will help you start growing your own food successfully.


I wrote an earlier version of this review for the Comics Journal.

Joseph Tychonievich
Liz Anna Kozic

Flame Weeding

Commiseration and sympathy to ice-blasted farmers and gardeners

Visits to my website shot up over the weekend. People are checking out my Winter-Kill Temperatures of Cold-Hardy Vegetables as they are dealing with temperatures considerably colder than they ever expected for their region.  I hope you can find some helpful information there while you triage your crops into “OK with these temperatures, can be left alone”/”might die, need help”/”will definitely die, no point in trying to save them”.

Q and A

Next a couple of questions that people left on the contact form, that I thought others might be interested in.

Q1. Is there an easy way to figure out what vegetables I can plant to maximize my space and yield. I am not sure if its my soil or sunlight availability in my backyard garden.

A. Most vegetables do need at least 6 hours a day of sunlight, so as we get closer to spring, assess various spots in your backyard. Maximizing use of the space includes careful choice of plant spacing, but also following one crop with another, or squeezing crops in between others. There’s no quick answer. Search my site for Succession Planting, Crop Spacing, Choosing Crops.

Q2. I am currently looking for Onion seeds or seedlings to purchase for approximately 1hector to plant. We based in the Free State Area.

A. South Africa? Sorry, I have no idea what is available where you are. 1 hectare is a huge area for onions, especially if you have never grown them before. Use transplants, not direct-seeded onions. Choose varieties adapted to your latitude, or else they may never grow big, or may not dry down and store well.

Flaming can be used for weed control, pest control, or crop termination.

Flame weeding can be used for carrots and beets before emergence.
Photo Brittany Lewis

Our introduction to flame-weeding was via the first article I ever read in Growing for Market magazine. It was about flaming for pre-emergence weed control in carrots. It sounded like such an effective method that we bought a Red Dragon flamer and never looked back! I remember saying and writing that it worked so well it felt like cheating!

Our flamer

We use a handheld flamer attached to a propane cylinder that is in a wheelbarrow pushed by a second person behind the first. This person also acts as a “fire warden.” Some growers mount the propane on a backpack frame. Walking along the aisle between beds and wafting the wand diagonally back and forth across the bed takes about ten minutes for a 100′ (30 m) bed. Flame-weeding alone can reduce hand-weeding to one hour/100′ (30 m). Hand-weeding can be reduced to 6 minutes/100′ (30 m) by flame-weeding after using stale beds which have been hoed three or four times.

Stale seedbed flaming for weed control

In the stale seedbed technique, the bed is prepared and watered ahead of planting time and one or more flushes of weeds are germinated and flamed or hoed off. Flaming avoids bringing any new weed seeds to the surface. To sow large crop seeds into a seedbed that has already had the weeds removed (by flaming or other stale seedbed technique), you can use a stick seeder or easy-plant jab planter. Making furrows for small seeds will inevitably activate a few weed seeds along the rows.

Flame weeding, pre-emergence

Flame weeding a carrot bed.
Photo Kati Falger

Carrots, beets and parsnips are ideal crops for pre-emergence flame-weeding. They do very poorly with competition, and grow more slowly than weeds, consuming lots of time hoeing, cultivating and hand weeding to get good yields. Flame weeding can change all that, with pre-emergence either as part of a stale seedbed technique, or post-sowing.

The latter method is to prepare the bed, sow the seeds, water, and then monitor carefully. The day before you expect the carrots to emerge, flame across the whole surface of the bed. Use a soil thermometer and the table here to figure out which day to flame.

Table of vegetable seed germination as a function of soil temperature

 

Days to Germinate 50F (10C) 59F (15C) 68F (20C) 77F (25C) 86F (30C) 95F (35C)
Carrots 17.3 10.1 6.9 6.2 6.0 8.6
Beets 16.7 9.7 6.2 5.0 4.5 4.6
We sow “indicator beets” with our carrots so that we know when to flame-weed them
Photo Kathryn Simmons

People who use pre-emergence flame-weeding for carrots can use a few “indicator beet” seeds sown at one end of the bed to show when to flame. As soon as you see the red loops of the beet seedlings breaking the surface, flame the carrots. (But look for carrots too, just in case!) Beets are always a bit quicker than carrots in germinating. Note that beets are about half a day ahead of carrots at 50°F–68°F (10°C–20°C), but more than a day at 77°F–95°F (25°C–35°C). The challenge with carrots is to keep the soil surface damp until they come through. As an indicator for beet seeds, you can use a few radish seeds.

Another way to get an alarm call is to put a piece of glass over part of a row. The theory is that the soil under the glass will be warmer and the crop there will come up sooner than the rest. I tried this once, but the soil under the glass dried out, and those carrots came up later than the rest! Nowadays we have a “no glass in the garden” rule, for safety, so I use beets, the thermometer and the chart.

See the useful resource Flame Weeding for Vegetable Crops  from ATTRA

Flame-weeding growing crops

Potatoes can get impossible to hill when you’d like to if you have wet weather, and this is where flaming can save the day. Potatoes may be flamed at 6″–12″ (15–30 cm) tall, to kill weeds without damaging the potato plants. After that, flaming is not recommended.

Sweet corn can be flame-weeded after planting, either pre-emergence or, with care, after the crop is two inches (5 cm) tall, using a directed flame.

Onion and garlic crops can be flame-weeded when relatively mature. Flame-weeding can achieve as good results as hand-weeding using one-third of the labor. Flame-weeding can damage young plants (four or fewer leaves), so bide your time. Direct the flame at the base of the plants, in the morning, when the plants are turgid. This technique is for unmulched crops. Naturally, if you have used straw or hay mulch, flame-weeding is not such a smart idea!

Peanut seedlings can be slow to emerge, so pre-emergence flame-weeding may be helpful. The seedlings look somewhat like peas or clover. Because they grow slowly for the first 40 days, they will not thrive if you lose them in weeds (guess how I know?!).

Flaming for ending potato growth

Potato plants come to a natural end when the leaves die, after which no further growth can be induced in them. Once the tops die, the potato skins start to toughen up. If you are growing storage potatoes and are impatient for the end to come, you can mow off the tops or flame them, to start the skin-thickening process, which takes around two weeks. The potatoes are ready when you can rub two together without any obvious damage to the skins.

Flaming for pest control

Pest habitat includes all those half-wild edges and odd corners. You can reduce the pest count in these havens by mowing, hand weeding, or flaming. Be sure not to remove all the habitat for beneficial insects while you do this.

Colorado Potato beetle late stage larva
Photo Pam Dawling

Colorado potato beetles can be tackled by flaming while the potatoes are less than eight inches (20 cm) tall, as an effective pest control measure. It won’t kill the potato plants. Choose a warm sunny day when the pests are at the top of the plants. Flaming can kill 90 percent of the adults and 30 percent of the egg masses, according to ATTRA.

Harvesting from bean plants with bad bean beetle damage.
Photo Wren Vile

Mexican bean beetles can be killed by flaming after harvest for that planting is finished. Flaming will kill the plants too. We used to plant six or seven successions of beans, every two weeks, then flame the old plants when the pest count got too high, and move on to a newer planting. Nowadays we buy the Pediobius parasitic wasp to deal with the MBB, and we can sow beans less often and harvest them for longer.

Flaming trap crops

Young turnips (with flea beetles!) in need of thinning for cooking greens.
Photo Pam Dawling

Flea beetles can be lured by a row of mustard greens. 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.

Striped cucumber beetle in squash flower. Photo Pam Dawling

Cucumber beetles  have a preference for some particular squash varieties, which may be grown as a trap crop: Cocozelle summer squash, Seneca and Dark Green zucchini are all “cucumber beetle preferred”! When beetles accumulate in the trap crop, flame it or till it in.

Stink bugs: Russ Mizell has published a paper on trap cropping for native stink bugs in the South. He recommends buckwheat, triticale, sunflower, millet, field pea and sorghum. A succession of trap crops including these and others such as pumpkins, cowpeas and other small grains (which are most attractive in the milk or soft dough stage) could help. Flame the trap crops when the stink bug numbers in the trap crop build up.

Excerpted and adapted from Sustainable Market Farming

Repurposed stroller makes a fine flame weeder.
Photo Sustainable Harvest Farm Kentucky

Root Crops in February

 

Large Smooth Prague celeriac. (Currently sold out Feb 2021)
Photo Southern Exposure Seed Exchange

Root Crops to Plant in Central Virginia in February

We sow no root crops in our hoophouse in February. It’s too late for radishes or turnips. If you are in a place colder or darker than winter-hardiness subzone Zone 7a, with an average minimum temperature of 0° to 5° F (-18°C to -15°C), see Root Crops in January.

If the soil outdoors is dry enough and not frozen, we spread compost on the raised beds we plan to plant in February and March, and till in the compost. Root crops that we sow outdoors here in February include carrots #1 and turnips in mid-February, and carrots #2 and radishes in late February. It’s true not much growing happens in February, but it helps us if we are able to get some crops planted early, leaving us more capacity for other crops once those are in the ground. And if the soil isn’t dry enough, we just do those jobs as soon as we can. We would hate to miss an opportunity!

Carrot Bed Prep

One of our many carrot beds, looking good.
Photo Kathryn Simmons

Carrots do very poorly with competition from weeds or too many other carrots. You can make use of the Stale Seedbed Technique, preparing the bed ahead of time, and flaming or hoeing one or more flushes of weeds as they germinate. I’ll do a separate blogpost on flame-weeding soon, as I have too much info to squeeze in here. It works so well, it feels like cheating!

Carrots are small seeds, needing a fine tilth (small soil particle size and good texture – not likely to crust or blow away).  Good information on crop spacing for maximum yields, or biggest vegetables is in an out of print book, The Complete Know and Grow Vegetables by JKA Bleasdale, PJ Salter, and others. For maximum total yield of carrots, they recommend 1.5” x 6” (4 x 15cm). You get medium sized carrots. For early carrots go with 4 x 6” (10 x 15cm) to minimize competition and get rapid growth. If you want to have rows more than 6” (15cm) apart, calculate the area of these optimum spacings, then divide by your chosen row space. For example, if your rows are 12” (30cm) apart, the carrots can be as close as 0.75’ (2cm) if total yield is more important than individual size, or 2” (5cm) for fast early carrots. We do five rows in a 4 ft (1.2m) bed, so the rows are about 10” apart, with the outer rows 4” (10cm) from the bed edge.

Young Carrot Plants After Thinning. Photo Kathryn Simmons

Carrot Thinning and Weeding

Remember to thin carrots as soon as you can see them well enough to do so. We usually hoe between the rows first, then crawl along thinning and weeding. It does take time! But you won’t get good carrots without thinning, unless you either have a precision-seeder that drops one seed per inch, or pelleted seed which you can sow at one per inch. Precision seeders like the Jang are expensive, but worthwhile if you need to use it every week. Pelleted seed costs more than raw seed, and its big advantage is traded off for two other disadvantages: The soil has to be kept well-watered until germination or else the clay coating will imprison the seed forever, and the seed does not store for long – don’t keep any over for next year.

Greenhouse Root Crop Sowings for Transplants

The only root crops we ever transplant are celeriac and kohlrabi (a stem vegetable really, not a root). I have transplanted many things and I am skeptical of books saying this or that can’t be transplanted, but not beets or rutabagas, which I hear people transplant as soil blocks or plugs. So try it if you think it will help.

Celeriac

Flats of celeriac seedlings.
Photo Kathryn Simmons

We have grown both Diamante (100 days from transplanting) and Large Smooth Prague (110d), and strongly prefer Diamante, as it seems to us to be more tolerant of warm weather, less prone to rot, and easier to clean. Several growers say that Diamante and Brilliant are virtually indistinguishable.

This crop likes rich soil with lots of organic matter, some shade from mid-day and afternoon sun, and ample water without sitting in waterlogged soil. We make sure to choose beds in a shadier part of the garden. Celeriac can rot if too damp, so keep it weeded and remove some of the lower leaves to improve airflow. A pH 5.8-6.7 is ideal. Celeriac can benefit from seaweed as a foliar spray, or side-dressing with compost during the long growing season.

Celeriac requires long steady growth, and the challenge is to prevent checks to growth. The Virginia climate is on the warm side for celeriac, it prefers cooler areas, but we have good success if we pay attention at a few critical times. Celeriac can tolerate frost quite well, so there is no hurry to harvest in the fall.

Sow seeds 1/8″(3mm) deep, and keep the soil surface moist. The minimum germination temperature is 40°F/5°C, and the optimal range 59–70°F/15-21°C. Germination is slow, typically 14 to 21 days, and it takes 10-12 weeks to grow to transplant size, so start in plenty of time. We sow in open flats, then spot out (prick out) into deeper flats. We sow February 10, which is about 10 weeks before our last frost date. Celeriac can be sown from 67 days before the last frost date to 184 days before the first fall frost date, but you don’t get large roots unless you have plenty of growing time.. If your climate includes long chilly springs, I’d suggest starting 12 weeks before the last frost date.

Emergence takes at least 12 days at 59°F/15°C and 7 days at 68°F/20°C. The ideal temperature is 68°F/20°C day, and 59°F/15°C at night. The fluctuating temperatures, with nights cooler than days by 9°F/5°C, help speed germination. Another factor when choosing germination temperature to aim for, is that at 59°F/15°C, only 40% of the seeds produce seedlings, compared to 97% at 68°F/20°C.

Celeriac should not be hardened off by reducing temperatures, as that can cause them to bolt. More than about 9 night temperatures below 55°F/12°C will cause bolting. Plants can have their watering reduced to help them get ready for the big outdoors. Use rowcovers if a cold spell arrives after you have planted them out, or if you know cold weather is likely to return. Falling apple blossom is a phenology sign that conditions are suitable.

See Root Crops in May for transplant info

See SESE’s Celery & Celeriac Growing Guide for growing information.

Kohlrabi

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

Kohlrabi is very easy to grow, treat it just like cabbage or kale.

It can be direct-seeded, but for an early crop, especially if you live in a climate like ours where spring turns into summer very quickly, use transplants. We don’t grow a lot, only 180 feet (55m) in total for 100 people. We also grow kohlrabi in the fall, transplanting bare root transplants from nursery seedbeds around August 3. We grow twice as much in fall as spring, because we can store them for winter.

We have grown both Early White Vienna and Early Purple Vienna. Growing both provides for pretty harvests. We sow February 8 at 4 seeds/inch (0.5 cm apart) in open seed flats, aiming to have the plants spotted out, hardened off and transplanted outdoors with rowcover on March 13. Fast work!

Root Crops to Harvest in Central Virginia in February

Hakurei turnips harvested late January.
Photo Pam Dawling

As for January, in central Virginia, there are normally no roots that we could be harvesting outdoors in February except parsnips, Jerusalem artichokes and horseradish.  We do have horseradish, but not the others. Of course, you can only dig up root crops if the ground is not frozen!

We have had outdoor night temperatures of 16°F/-9°C and 12°F/-11°C. This winter we have some carrots “growing” in the fresh air and some late-sown beets under rowcover. I don’t think we’ll get roots from the beets, but the leaves might make a nice change from brassicas as cooking greens.

In the hoophouse our radishes #3 (sown October 30) will come to an end by 2/1. Our #4 radishes will get harvested this month. Our #5 radishes, sown 12/23, will feed us from then until around April 7

We still have some of our first turnips (sown around October 13) until mid-February, and they have reached a really good size, thanks to early thinning. This month we can harvest the second sowing (October 25). We thinned turnips #2 in early January. They are looking good too.

Red Round turnips in our hoophouse in late January.
Photo Pam Dawling

We have not yet needed to unroll our inner rowcovers in the hoophouse. We wait until we expect it to get down to 8°F (-13°C) outdoors, as we like to avoid extra work!

Other Root Crop Tasks in Central Virginia in February

Potatoes stored in crates in our root cellar.
Photo Nina Gentle

Check stored vegetables

Stored crops need to be checked for decay at least once a month, preferably once a week now the days are getting longer and the temperatures will get warmer. From storage, we can eat beets, carrots, celeriac, kohlrabi, parsnips, potatoes, rutabagas, sweet potatoes, and turnips, if we grew them.

Special Root Crop Topic for February in Central Virginia

Wrap up the winter planning

Our garden planning wraps up by mid-February, with all the budgets, crew selection and shift decisions (afternoons in cold weather, mornings in hot weather –  we’re mostly half-day gardeners, with one or two stalwart all-day workers)

Order summer cover crop seeds

Buckwheat cover crop in flower.
Photo Pam Dawling

For early spring, if we find an area without a winter cover crop and we realize we won’t plant it with a vegetable crop for at least 8 weeks, we sow oats. They will smother weeds and add organic matter to the soil when you till them in.

If you have not already ordered summer cover crop seeds, this would be a good time to do so. Cover crops suppress weeds, add organic matter, feed the organisms in the soil and attract beneficial insects, birds and amphibians to feed and reproduce. Biodiversity encourages ecological balance that can help reduce plant diseases and pest attacks. Have a goal of No Bare Soil. Seek out odd spaces to fill with cover crops.

Once frosts are past, buckwheat is an easy cover crop. Its flowers attract beneficial insects, and it is a very manageable (not too tall) fast-growing crop. Buckwheat can be in and under in a month.

Just as fast is mustard, but we don’t grow that because it’s a brassica and we grow a lot of brassica food crops. Keeping a good crop rotation is important to us. Also we have harlequin bugs and we don’t want to feed them year round.

Sorghum-sudangrass hybrid is a fantastic, huge warm weather grass type cover crop, but don’t grow it if you have only a lawnmower, a scythe or a nylon line weed whip to cut it down! For smaller scale gardens, choose Japanese millet.

Soybeans, southern peas and sunn hemp are easy legume cover crops for warm weather, providing nitrogen for the next crop.

Cover cropping is a big topic. See my book Sustainable Market Farming for more. Here I’m just pointing you in the right direction enough to order seeds soon. You can read up more later.

Early Lettuce Production

Young Salad Bowl lettuce
Photo Wren Vile

Early Lettuce Production

Growing early season lettuces involves choosing suitable types and varieties (cold-tolerant and fast-growing), having successful production methods, and a good schedule. Harvesting early in the year might mean fast production in January and February, or it might mean starting in the fall and overwintering the plants. See my post series Lettuce of the Month, for ideas on varieties and techniques throughout the year.

Our Climate Zone in central Virginia is 7a, which means our annual minimum temperature averages 0°F to 5°F (-18 to -15°C).  The average date of the last spring frost is April 30 (later than 5/14 one year in 10). We grow lettuce outside from transplants from February to December, in a solar greenhouse from October to early March, and in a solar-heated double-layer hoophouse from October to April.

Swordleaf, Red Salad Bowl and Bronze Arrow lettuces.
Photo Bridget Aleshire

Lettuce Types

There are several different general types of lettuces. In terms of growing speed, the baby lettuce mixes and the leaf lettuces produce harvests soonest after sowing. Loose-leaf lettuces are very useful because you can harvest individual leaves while you’re waiting for the heads to reach full size.

Leaf types are ready for harvest 45-60 days from direct seeding, 30-45 days from transplanting. Bibbs mature in 60-75 days, most head lettuce need up to 80 days from seeding, or 60-70 days from transplanting in spring. Romaines are slower-growing (70 days or more). Batavian lettuces (also called French Crisp) are tasty, thick-leafed varieties that have excellent heat and cold tolerance. Icebergs mature in 75-100 days.

Beautiful baby lettuce mix in our hoophouse.
photo Wren Vile

Baby lettuce can be cut 21 days from seeding, (except from November to mid-February, when it may take 2 or 3 times as long).

Bolt-resistance generally goes from Leaf types (first to bolt), through Romaines, Butterheads, Bibbs, to Crispheads.

I like to sow four lettuce 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:

  1. Early Spring (Jan – Mar), 6 sowings
  2. Spring (April – May 15), 5 sowings
  3. Summer (May 15 – Aug 15), 17 sowings
  4. Fall (Aug 15 – Sept 7), 9 sowings
  5. Winter indoors, Sept 8 – 27, 9 sowings

 Lettuce Varieties

Bronze Arrow lettuce ultra-closeup. Photo Bridget Aleshire

It’s important to grow the right lettuce variety for the conditions. For earliest harvests, consider a different, faster, variety than you have usually grown. Some of the early spring lettuce varieties are often useless here if sown after mid-March, or even mid-February, because they bolt prematurely as the Virginia spring flips from cold to hot (and back again, grrr!). Varieties we only sow until 2/15 include Bronze Arrowhead (46 day leaf lettuce); Buckley, Ezrilla and Hampton (55d multi-leaf types); Merlot (60d), Midnight Ruffles (48d) and Oscarde (45d) (leaf lettuces). Antares (48d) Panisse (48d) and Revolution (38d) leaf lettuces we can sow until 3/15.

Nancy bibb lettuce
Photo Bridget Aleshire

Others that we like in early spring go on to be useful later in spring too. In this category are Buttercrunch (a small 50d bibb); Nancy (58d) and Sylvesta (52d) (two big green bibbs); Pirat (55d red bibb), Green Forest (56d), Kalura (57d) (two green romaines); and New Red Fire (55d), our reliable Salad Bowl (45d) and Red Salad Bowl (46d), Starfighter (52d), and Swordleaf (53d) (leaf lettuces)

New Red Fire lettuce.
Photo by Bridget Aleshire

The baby lettuce mixes we like are Fedco’s 2981 LO Lettuce Mix OG (contains at least six different lettuces) or Johnny’s Allstar Gourmet Lettuce Mix #2310 (including green and red oakleaf, green and red romaine, lollo rossa, and red leaf lettuces). One gram sows 25 ft, one ounce will sow about 600 feet.

For those with challenging growing conditions, both companies offer other specialized selected mixes.

Cold-tolerance of lettuce

Red Tinged Winter and Tango lettuce in our hoophouse in December.
Photo Pam Dawling

Lettuce is more cold tolerant than many people realize. If plants are sufficiently hardened (prepared by growing in gradually lower temperatures), they can withstand freezing. At 22°F (-6°C), large leaves of some lettuce will die. Medium-sized plants with 4-10 leaves (Marvel of Four Seasons, Olga, Rouge d’Hiver, Tango, Winter Density may survive unprotected down to 15°F (-9.5°C). Half-grown lettuces are more cold-hardy than full-sized plants.

Lettuce Crop Requirements

Flats of lettuce transplants in our cold frame in April.
Photo Pam Dawling

Lettuce seed remains dormant unless triggered by adequate levels of light and temperature. It needs light to germinate, so don’t sow too deep: ¼-3/8″ (6-9 mm) is enough. Some sources recommend not covering the seed at all, but this can make it hard to keep the seed damp. The light dormancy is more pronounced in fresh seed, which has higher levels of the hormone that controls germination.

Soil temperature is important. I have a table of optimum soil temperatures for germination in The Year-Round Hoophouse The optimum temperature range for lettuce germination is 68-80°F (20-27°C). It takes 7 days to germinate with a soil temperature of 50°F (10°C) or 15 days at 41°F (5°C), and only 4 days at 59°F (15°C). Even a few hours at temperatures higher than the optimum can induce dormancy.

Lettuce transplants prefer a well-draining soil high in organic matter, and with a pH of 6.0-7.0, not lower. Optimum growing temperatures are 60-65°F (15-18°C), with a minimum of 40°F (4.5°C) for any growth to occur. Lack of water will lead to bolting, and/or bitterness. Keep them growing quickly for good flavor.

Lettuce in January

A flat of newly emerged lettuce seedlings
Photo Kathryn Simmons

We plan to start harvesting heads of lettuce outdoors from April 15. Before then we will harvesting lettuce in our greenhouse and hoophouse.

In mid-January we sow four lettuce varieties, to become our first outdoor transplants. I recommend sowing several varieties each time to spread your risks, if one kind bolts or suffers disease. I choose varieties that cover the range of colors and shapes. I select hardy types that are fast-maturing. Buttercrunch green bibb lettuce is one of my favorites for early spring. One of the Salad Bowl lettuces, red or green, is also usually in my first sowing. The Salad Bowls are so reliable and productive! New Red Fire has become another reliable lettuce stand-by for us. It was suggested to me by neighboring Virginia farmer, Gary Scott of Twin Springs Farm. It is more of a leaf lettuce, and doesn’t exactly head up, although it can be cut as admittedly lightweight heads. It works fine as a leaf lettuce, harvested by the cut-and-come-again method. We grow New Red Fire year round, it’s that adaptable and easy-going. We haven’t found many good full-size red romaines. Bronze Arrow  has worked well for us and we were harvesting it in early May.

We grow all our outdoor lettuce as transplants. In spring we sow in 3″ (7.5cm) deep open wood seed flats, 12″ x 24″ (30 x 60cm). We make four little furrows by pressing a 12″ (30 cm) plastic strip (aka a ruler!) into the seed compost. We sow the seed, label it, cover it lightly, water, and put the seeded flats in our germinator cabinet. The first flat of the year takes about 9 days to germinate.

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

Once the seedlings are big enough to handle, we spot them out into 4″ (10 cm) deep flats (also 12″ x 24″/30 x 60cm). We have a plywood dibble board with pegs evenly spaced about 2.5″ (6 cm) apart. We aim to harden off the lettuce for two weeks in the cold frame before transplanting into the garden beds with thick rowcover on hoops to protect the lettuce from the still-cold outdoors. To be ready for harvest 4/15, these seeds have to become full size lettuces in 88 chilly days.

Seeds can instead be sown in cell packs or plug flats, putting three seeds in each cell, and later reducing to one seedling with scissors. Cells or pots with diameters from 1-2½” (2.5-6cm) can be used. The 96-cell size (1×1½”/2.5x4cm) works well, although the 200-cell size (1×1”/2.5×2.5cm) is possible if you can be sure to get the transplants out before they get root-bound. If warm germination space is limited in early spring, sow seed in a small flat, then “spot” the tiny seedlings into bigger flats, 606 (2×2¼”/2.5x6cm) cell packs, or 32-pack square pots to grow on in cooler conditions before planting out. Soil blocks are also possible, but take more time.

We make a second sowing on January 31. The intervals between sowings at the beginning of the year are long, because later sowings will catch up to some extent with earlier ones. Most crops grow faster in warmer weather.

Lettuce in February

We sow lettuce twice in February – 14 days apart. We get ready to transplant our first outdoor lettuce, to feed us mid-late April. Our first sowing of baby lettuce mix in the hoophouse comes to the bitter end, and the second sowing is awaited. We continue to harvest leaves from the large lettuce we transplanted in the hoophouse in October.

Lettuce in March

Lettuce with sclerotinia drop.
Photo Pam Dawling

We sow flats of lettuce every 10 days in March. March 9 is our goal for a transplanting date outdoors for our first 120 lettuce (about one week’s worth for 100 people).

Here is a link to a helpful publication from eXtension: Disease Management in Organic Lettuce Production. Horribly useful photos!

Baby Lettuce Mix

Baby lettuce mix can be ready in as little as 21 days from mid-spring to mid-fall, longer in early spring. A direct-sown cut-and-come-again crop, the plants regrow and can be harvested more than once in cool seasons. We sow 10 rows in a 4’ (1.2m) bed, 4.5” (11cm) apart. 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. Rake after harvest with a fine leaf rake to remove outer leaves and cut scraps. If you want to make more than one cut, you will need to remove anything that isn’t top quality salad while you can see it. Larger scale operations have harvesting machines.