<div style=”margin-bottom:5px”> <strong> <a href=”http://www.slideshare.net/SustainableMarketFarming/fall-vegetable-production-60min” title=”Fall vegetable production (60min) – Pam Dawling” target=”_blank”>Fall vegetable production (60min) – Pam Dawling</a> </strong> from <strong><a href=”http://www.slideshare.net/SustainableMarketFarming” target=”_blank”>Pam Dawling</a></strong> </div>
Here’s the presentation I gave at the VSU 2013 Commercial Berry and Vegetable Filed Day at Randolph Farm, Petersburg on Thursday (6/27). Actually this slide show has some extra slides that I had to cut out to fit the time available. Registration for the field day had doubled compared to last year and reached 500. I don’t know how many were at the presentations, maybe 250. The other option was to continue the outdoor exploration of the research plots.
One section I would have loved to have seen, if I hadn’t been signing and selling books, and answering questions about VABF, was Clif Slade’s “43560” (Forty-three five sixty”) plot. He is aiming to demonstrate the viability of earning $43560 per year from one acre (43560 square feet) of intensive vegetable production. There are some You-Tubes about this project on http://www.youtube.com/user/VSUCoopExtension/videos
Around mid-July, check out http://www.vsuag.net/
for a video compiled by Michael Clark, combining my slideshow and me speaking.
Meanwhile, back at the farm, I’m sowing fall broccoli, cabbage and senposai, weeding sweet potatoes, sowing another succession of beans and one of edamame. More of our time is spent harvesting these days. Today we pulled a bag of beets, 2 buckets of beans, 2 buckets of lettuce (we’ll have a short gap until the next bed comes in), 6 buckets of broccoli, one bucket each of cukes, squash, zucchini, turnips and kohlrabi. Most of our crops are getting harvested every two days at this point (except lettuce, cukes and zukes). So no cabbage, kale, chard, scallions, blueberries or celery today.
Here is our task list for the Twin Oaks Garden in March. We’re zone 7, our average last frost is April 20. You’ll need to adapt this information for your climate.
Lettuce factory during March: Transplant 1/3 bed each, for sowings #1, 2, 3. Cover. Sow #5, 6 this month.
1st March: chit seed potatoes in flats for 2-4 weeks with bright light in basement.
Check irrigation and hoses. Buy replacements as needed.
Buy twine: make up to 6 binder and 2 baler twine.
Inventorycover crop seeds, buy buckwheat, sorghum-sudan, pearl millet, clover or other summer cover crops.
Compost needed in March: 6-9 tractor buckets for beds, 8-20 to disk in.
Compost and till raised beds for April plantings – carrots #4 & 5, lettuce 4-6, beans #1.
Sowradishes, (spinach), turnips, scallions #2 and cover. Last date for sowing fava beans is 3/14. Sow peas only 1/2″-3/4″ deep. Cover.
Transplant fall sown onions ½-3/4” deep, when no thicker than pencils; cabbage #1, lettuce #1.
In greenhouse sow peppers, eggplant, hoophouse squash, Alyssum, bulb fennel, broccoli #3 (1 week after #2, quick, heat tolerant varieties). Test and condition sweet potatoes for 2 to 4 weeks at 75- 85°F, 95% humidity.
Cut seed potatoes and heal for three days: two buds on each piece, one for insurance. Ginger too.
Plant potatoes when the weather becomes suitable (when daffodils bloom.). Reduce sprouts/piece to 2. See Perfect Potato Planting card.
In greenhouse: sow main crop tomatoes, lettuce #5 [sesame]. Protect cabbage and broccoli at 5-8 true leaves from cold stress (<40°F for a few days, or longer at 50°F).
Plant sweet potatoes in flats in glass door germinator cabinet.
Transplant collards, kale, kohlrabi, senposai,lettuce #2, scallions #1, mini-onions. [spring-sown onion seedlings in clumps @12″, 1/2 to 1” deep].
Till raised beds before weeds seed, and sow oats (by 31st) if not needed for 6 weeks or more, (eggplants, cucumbers, squash, tomatoes, celery, later lettuce). Sow clovers until 3/15 for long-term cover; or winter rye to wimp out (it does not head up in warm weather).
#2 Spring Tractor Work Mid-March – Disk area for corn #1&2,
Late March: [side dress garlic & onions with compost]
In greenhouse: sow Roma tomatoes, lettuce #6, nasturtiums, chard and leaf beet in soil blocks or plug flats; squash #1 & cukes #1 in blocks or plug flats (not before 3/25). Spot eggplant. Sweet Potatoes: Cut slips at 6 to 12”, put in water. Once a week, plant rooted slips in 4” flats. Plant ginger in flats or crates.
Buy seed potatoes for June planting, and refrigerate them. Keep at 40-50°F in the dark, until 6/1.
Sowleeks & other little alliums in seed bed, update map; carrots #4 outdoors. Sowkohlrabi if transplants fail, thin to 6” later.
Compost & till beds for late April planting: cucumbers #1, edamame #1, squash #1, peanuts, celery, parsnips, chard, cowpeas #1, (sesame). Can sow oats till 3/31 in beds not needed for 6 weeks.
Work on thePerennials in March: Really finish weeding, fertilizing and mulching them! Early in the month plant new blueberries, grapevines, raspberries, strawberries if not done in fall. Divide and replant rhubarb if needed. Water if needed, especially new beds. Set up irrigation and ropes where needed. Put up ropes for raspberries, mow between grapes. Maybe till up aisle in grapes and sow clovers & grass.
Or you can simply go to SlideShare and search for “Pam Dawling”
Next I’m working on how to make the handouts more accessible, although SlideShare does make this less necessary for the workshops where the slideshow includes everything on the handout. The Intensive Vegetable Production on a Small Scale handout does have material I couldn’t include in such a short slideshow.
Meanwhile in our garden we’re weeding the asparagus and sowing more seeds in the greenhouse: celery and celeriac, kohlrabi, broccoli and more cabbage. The first lettuce and cabbage are ready for spotting out. I’m hoping the sun will come out this afternoon and I can enjoy myself doing those tasks. Tomorrow we might prune the blueberries.
I’ve been busy putting our seed orders together. As we grow so many different crops, it’s quite a time-consuming process. And I hate to buy too little and be out in the field on planting day, looking at an almost empty packet. Equally, I hate to buy too much, which either wastes money (if we throw the extra away), or else causes us to risk sowing seed that really is too old, and won’t do well. I keep a chart of how long different types of seed last:
(From Sustainable Market Farming, (c) Pam Dawling, New Society Publishers, 2013)
“Opinions vary a bit about how many years seeds of different vegetables are good for. The fuller story is that storage conditions make a big difference. You can make your own decisions, weighing up the information supplied, your knowledge of how carefully you stored the seeds, the information on each packet about percentage germination when you bought it, and the economic importance to you of that particular crop. If you always transplant lettuce, as I do, you can risk one of your four varieties in that sowing coming up poorly, and just plant out more of the other three if it fails. Many seed catalogs include information about seed longevity, and so does Nancy Bubel in The Seed Starters Handbook.
Rather than deteriorating with age, some very fresh seed has a dormancy that needs to be overcome by chilling (lettuce). Other seed contains compounds that inhibit germination. These can be flushed out by soaking in water for about an hour (beets).
Another of the challenges with seed ordering is converting between grams, ounces and seed counts. Here’s a helpful table of 1000 Seed Weight for 13 crops.
Our main seed suppliers are Fedco, Johnny’s and Southern Exposure. Fedco has great prices, especially on bulk sizes, great social and political commentary in the catalog, and no glossy pages. Johnnys has some good varieties that Fedco doesn’t, and a ton of useful information tucked away on their website. Southern Exposure is best on southern crops and heat tolerant varieties which we can’t expect seed companies in Maine to specialize in. Plus, SESE are my friends and neighbors.
This year we are trying some new varieties. Generally we like to have some reliable workhorses that we know well, and trial a few new things, especially if we hear our favorite varieties are no longer available. Last year our Nadia eggplant couldn’t cope with the heat. For a while in early summer they didn’t grow at all – no new flowers, never mind new fruit. So next year, alongside Nadia I’m trying 3 that should deal better with heat. Florida Highbush is open-pollinated, from the Seed Savers Exchange. Epic and Traviata are hybrids from Osborne Seeds.
I also bought some Sugar Flash snap peas from Osborne. We have been big fans of Sugar Ann, but I’ve heard Sugar Flash is even better on flavor, yield and harvest period. We’re going to find out!
For a couple of years we really liked Frontier bulb onions as a storage variety for this climate and latitude (38N). Frontier disappeared from the catalogs of our usual suppliers and we tried Gunnison and Patterson. This year – no Gunnison! And we didn’t get a good test of Patterson last year, as we failed to weed our onions enough, after an initial enthusiastic good go at it. We were looking again at Copra, one we grew some years ago (before we found Frontier). I lucked out when I decided to see if Osborne had Gunnison, while I was shopping there. they didn’t, but they had Frontier! And then when I was shopping at Johnny’s, I found they did have some Gunnison for online sales only. So I ordered those too!
We’re also trying Sparkler bicolor sweet corn from Fedco and a drying bean I won’t name, as the seed is in short supply. And this year we’re hoping Red Express cabbage will prove to be a reliable little worker. We used to like Super Red 80, but had several years of poor results. Since then, none of the other red cabbages we tried have satisfied us in terms of size, earliness, productivity and flavor.
After a few years of poor pickling cucumbers, we’re going outside the box and trying West Indian Gherkins from Monticello, where they were grown by Thomas Jefferson (and some of the enslaved people, no doubt). These are not closely related to actual cucumbers, but are used similarly. I saw them growing in the Monticello garden when I was there for the Heritage Harvest Festival in September, and they are certainly robust and productive in hot humid weather. We’ll see how the pickles turn out!
My only other “impulse buy” was the Salanova Lettuce new at Johnny’s. They are 6 varieties of head lettuce designed to be used for salad mix at a single cutting. Quicker than snipping rows of baby lettuce with scissors. More fun than plain lettuce heads. They are loose heads of small leaves in various shades of green and red, and two “hairstyles”: frizzy and wavy.
Yesterday was our last garden crew shift of the year. It was a chilly day, so I was glad we had finished harvesting all our carrots while the weather was warmer. Washing carrots in cold water is tough! Our carrots totaled 41 bags, plus several buckets of culled Use First quality. I think that’s the most we’ve ever got for fall carrots. Part of our success has been the realization that we can grow 5 rows per bed rather than 4, and get more carrots from the same space. Last fall we failed to finish our initial thinning, mowed off part of the patch, and abandoned them. In spring we were surprised to find them still alive. I wrote about this in a post “Risking Zombie Carrots: weeding tiny carrots versus weeding broccoli” . This year we got through all the first thinning (to 1″), but didn’t finish the second (to 3″). We found that we got much the same tonnage from the once-thinned section as the twice-thinned. But yield is not the whole story. Our cooks prefer the bigger carrots, from the area that got properly thinned.
So, for our last shift, we liberated some of our garlic shoots from under over-thick hay mulch. This year we planted up to week later than we usually do, and the colder weather meant the shoots hadn’t emerged in time to be liberated before we stopped having shifts with the crew. The picture above shows where we’d ideally be at before the end of shifts. Yesterday we were able to work on two of the beds, but the shoots were quite small and hard to find. The third bed was even further behind (it was planted a day or two later). We roll the hay bales out over the patch immediately after planting, and the thickness does vary. It’s important to walk through and rescue any shoots trapped under thick clods of hay, or they can smother and die. So the last part of the patch remains for those of us year-round Full Crew to tackle on our own. In the winter we have one of us each day responsible for taking care of the hoophouse, putting blown-open rowcovers back and harvesting outdoor kale, spinach, leeks, and as long as they last, lettuce, celery, senposai and Yukina Savoy. This winter we still have some broccoli and cabbage too. Fiesta has been a good late maturing broccoli for us this year.
My book is fast approaching press-time. Kathryn finished her index and sent it in. I wrote “About the author” and sent in another photo to substitute for one that wasn’t high enough resolution. I’ll probably spend this weekend reading a pdf of the whole book, before it goes to press. And then I take off for a few days with friends, to rest and celebrate.
Here’s a photo Ethan just took last week of our hoophouse and its bounty.
Lettuce Factory: Sow lettuce in hoophouse, for January transplants.
Write Thank You Letter to Paracrew (part-time workers)
Early November: Finish up sowing cover crops in Nov. Can sow winter wheat in early November (won’t winter-kill). Sow wheat or rye in carrot beds by 11/30(?), or if too late for cover crops, just spread carrot tops on beds.
Sowonions to overwinter in hoophouse.
Plant hard-neck garlic when soil temp at 4″ deep is 50°F, and mulch immediately, not too thickly.
Plant soft-neck garlic.
Plant leftover small garlic cloves for garlic scallions and garlic greens.
Potato onions: till beds. 11/1-12/1: Plant medium-size (1½-2” diameter) potato onions, at 6”, or wider if supply is limited. Cover with ½-1” soil, then mulch. If planning a January planting of small potato onions, prep bed and roll mulch now.
Sow spinach (for spring harvesting) in early November if not done already.
Mid November: Free trapped garlic shoots from over-thick mulch, when 50% emerged.
Coverlettuce, spinach (“burns” below 10°F), celery, zukes & cukes and Chinese cabbage. Use double hoops for the spinach, celery, and the last lettuce bed.
Harvest: celeriac (hardy to 20°F), beets (15-20°F), turnips(20°F), kohlrabi (15°F), winter radish (20°F), rutabagas (OK to 20°F), carrots (12°F), parsnips (0°F) in that order. Wash and store in perforated plastic bags in walk-in cooler. Record yields.
After curing, store boxes of sweet potatoes in basement cage (55-60°F, 80-90% humidity).
Sortwhite potatoes in storage 2 weeks after harvest.
Spread lime or gypsum as needed, referring to soil analysis results.
Potato Onions: sell small ones (<1½”) or store on racks until January. Ideal conditions 32-40°F, 60-70% humidity, good ventilation, layers < 4” deep. Do not seem to suffer from freezing.
Winterize the rototillers and BCS mower.
Week 1: Check the accounts and prepare Budget Requests for economic planning. Write Informant. Revise Seed Inventory spreadsheet.
Week 2: Inventory seeds
Week 3: Inventory seeds
Week 4: Seed Inventory: proof reading, etc. File notes.
Perennials: Cut dead asparagus tops with weed whackers or machetes, and remove all ferns. Weed strawberries and spread sawdust in aisles. Weed and fertilize rhubarb, blueberries, asparagus, and spread cardboard and sawdust, (hay for asparagus if possible). Weed grapes, take vine cuttings. Transplant new blueberries if needed.
November Harvests: last outdoor lettuce (hardy to 15°F with rowcover), beets (15-20°F), broccoli (25°F), cabbage (12°F), cauliflower, celeriac (20°F), celery (15°F with rowcover), chard (10°F), fall greens, collards (5°F), fennel (25°F), kale (0°F), kohlrabi (15°F), komatsuna (15°F), leeks (fall leeks hardy to 12-20°F, winter ones to 5°F or lower), parsnips (0°F), scallions (25°F), senposai (12°F), spinach (0°F), tatsoi (10°F), turnips (20°F), yukina savoy (10°F).
December – Time to Rest
Perennials: see November. Cut fall raspberry canes (after leaves have dropped) with pruners, to the ground. Weed raspberries. Hang blueberry drip tape in the branches. Dig docks from asparagus patch.
Plant mediumpotato onions, if not done in November.
Drain and store the hoses and irrigation. Clean up stakes, labels.
Week 1: Prepare seed order spreadsheet. Decide seed order.
Week 2: Revise Lettuce List, lettuce Log. Spend last of money. Check expenditures and spend remaining budget. File the year’s accumulated notes.
Week 3: Put your feet up and read seed catalogs and inspiring gardening books
Week 4: Put your feet up and read seed catalogs and inspiring gardening books
December Harvests: cold frame spinach or lettuce, cabbage (hardy to12°F), celery (15°F with rowcover), chard (10°F), collards (5°F), kale (0°F), komatsuna, leeks (fall leeks hardy to 12-20°F, winter ones to 10°F or lower), parsnips (0°F), senposai (12°F), spinach (0°F), yukina savoy (10°F).
Here’s our list of tasks for October. If you garden in zone 6 or 7, your list might be similar. If you live in a very different climate zone, leave a comment about your list for October, and how many weeks different your area is from ours.
During the month
Weed and thin fall crops in raised beds, especially spinach and kale. Thin carrots to 3”, kale to 12”.
Lettuce Factory: Transplant sowing #37 to fill cold frames; #38, 39, 40, 41, 42 in Greenhouse beds (9″ spacing).
Watch the forecast and if frost is expected that night
Harvest peppers facing the sky, tomatoes, cauliflowers, corn, cowpeas, limas, eggplant, melons, cukes, okra, winter squash, Blues cabbage (hardy to 25°F), if not already done.
Double hoop and cover: lettuce, celery (hardy to 16°F with row cover).
Spring hoop and cover: squash, cucumbers.
Rowcover (no hoops): beans, Chinese cabbage, pak choy, Tokyo bekana, seedlings for hoophouse, collards (hardy to 10°F, but cover keeps quality).
Cold frames: Row cover between 32-28°F. Add lids between 28-15°F. Add quilts below 15°F.
Foliar spray greens with seaweed a few days before frost, to toughen them up.
Use overhead irrigation on peppers & tomatoes at night and some raised beds with tender crops.
Early Oct: Finish sowing spinach, kale by 7th for overwintering (last chance).
Transplantlettuce #37 to fill cold frames; #38, 39 in Greenhouse (9″ spacing).
Roll updrip tape from winter squash and sweet potatoes.
Movestored garlic from basement to fridge – store below 40°F or above 56°F, never 40-50°F.
Mid Oct: Till finished raised beds and sow wheat or rye before the end of the month.
Garlic Beds: Compost (5-6 tractor buckets), till and prepare beds.
Transplant lettuce #40, 41, 42, 43 in Greenhouse as needed, filling any gaps.
Get soil tests done, when soil is not too wet.
5thfall disking: By mid-month disk and sow cover crops where possible. Sow wheat or rye as covercrops – too late for oats or most clovers (Austrian Winter Peas Sept 15-Oct 24). Could sow winter wheat mid-Sept to early Nov (good for small plots that are hard to reach with the tractor) and after sweet potatoes).
Harvestpeanuts mid-late Oct after a light frost. Wash, dry, cure 6 days in solar dryer facing east (don’t heat over 85°F), store.
Harvest sweet potatoes before soil temps go much below 55°F, or night air goes below 50°F: on 3 mild days – generally in the week that first frost usually occurs (10/7-14). Even a few hours exposed to temps below 50°F will cause chilling injury. (Frost on the leaves does not of itself damage the roots). Clip vines, dig carefully, set tubers in plant-clusters to dry on the soil. Select seed tubers (med-size tubers from high-yielding plants). Save 100 Georgia Jet, 100 Beauregard, 20 each White and Jubilee. Cure in boxes with wood spacers and cover with newspaper, in basement with furnace going full time, for 7-10 days (85-90°F, 80-90% humidity). Use fans. Splash water on floor. Curing is complete when skin is undamaged after rubbing two together. Restack boxes in storage cage.
Harvest white potatoes before the first frost (average Oct 14) if possible. Cure in root cellar at 60-75°F for 2 weeks, with good ventilation, then cool the cellar to lower temperatures: 50°F by 10/31, then 40°F for the winter.
Late Oct:Transplant lettuce #44, 45, 46 as filler in Greenhouse. Double hoop and cover spinach.
Planning: List successes & failures from labels. Prepare Garden Planning Schedule, Crop Review Sheets. Clean labels after info is recorded. Pray for a killing frost. File crop record info. Audit labor budget and plan endgame. Plan main garden layout. Hold Crop Review meeting.
Clearwinter squash, tomatoes and peppers in order to sow cover crops, by 10/24 if possible. Sow rye alone or with crimson clover or winter peas. Crimson clover by 10/14; AWP, wheat by 11/8
6th fall disking: After the killing frost, or end of Oct if no frost: pull up tomato stakes and roll up drip tape, disk nightshades, melons, winter squash, sweet potato and white potato patches.
Check through veg in storage, squash once a week, white potatoes two weeks after harvest.
Perennials:Last mowing of clover in grapes in early Oct, not too short, and not too late in the year. Weed & mulch strawberry beds, and remove extra runners. Renovate if not already done. Start weeding, fertilizing and mulching the blueberries, raspberries, rhubarb and grapes.
October Harvests: Asparagus beans, beans, beets and beet greens, broccoli, cabbage, cantaloupes, carrots, cauliflower, celeriac, celery, chard, Chinese cabbage, collards, corn, cow peas, cukes, edamame, eggplant, horseradish, hot peppers, kohlrabi, komatsuna, leeks, lettuce, limas, maruba santoh, okra, pak choy, peppers, radishes, Roma paste tomatoes, scallions, senposai, spinach, tatsoi, tokyo bekana, tomatoes, turnips and turnip greens, winter radishes, winter squash, yukina savoy, zucchini. Could lightly harvest rhubarb before frost.
Weed and thin carrots and brassicas (kale to 12”).
Lettuce Factory: Sow hardy lettuce every 2 days till 21st, (3 rows/planting) then every 3 days. Sow #34-46 this month. Transplant 120 every 3-5 days (1/3 bed) #27, 28, 29, 30, 31, 32, 33 for last outdoor planting (Dec harvest). Transplant #34, 35, 36 9/24-9/30 for frames
Root cellar: air and cool to 60°F by mid-September
Collect seed from Roma tomatoes if necessary.
Screen compost and fill old greenhouse beds before October, for winter lettuce and spring seed compost.
Early Sept: Prepare and plant new strawberry beds if not done in late August, using rooted potted runners or plants carefully thinned from last year’s beds (see August for details).
Transplant collards and kale if necessary. Transplant lettuce #27, 28, 29, 30.
Retrieve spinach and onion seeds from the freezer. After acclimating spinach seeds, sprout 4oz/bed (1 cup/10,000 seeds) for spinach #1 in fridge for one week, then direct sow (if <68°F, and dead nettle has germinated). If still hot, sow (preferably pre-sprouted) spinach in Speedling flats in float tank. 9/20 is last sowing date for fall harvesting. [Could broadcast oats into spinach at planting time for weed control & cold weather protection.]
Sow if not done already: kale and collards by 9/15; turnips by 9/30; radishes, kohlrabi, daikon and other winter radish, miscellaneous fall greens, scallions.
Plant large potato onions this month or early in October, at 8” (wider if supply limited). Cover with ½-1” soil, mulch with hay.
2nd fall disking: Watermelon plot when 800 have been harvested. Roll up drip tape first, or move to new strawberries.
Mid Sept: 7-14 Sept is the best time to sowvetch & rye, 1:2, 2# of mix/1000 sq ft (75#/acre) on old spring broccoli patch; crimson clover and rye, 1:2, at 55#/acre.
Transplant lettuce #31, 32.
Sow 1st sowing of hoophouse seedlings (hoop and cover).
Bring 6 tractor buckets compost to hoophouse for fertilizing fall and winter crops.
Move stored onions from basement to fridge, after apples peak in mid-September, and space available.
3rd fall disking: corn #3, #4, #5. Part of corn #3 plot may be used for new strawberry beds.
Late Sept: Sowspinach #2 for spring harvesting (9/20-9/30), and 2nd sowing of hoophouse seedlings and cover.
Transplantkale for spring, filling gaps; lettuce #33, finishing up the last outdoor bed; [#34, 35 & 36 in cold frames?] Plant large potato onions (>2”) if not done earlier.
Move garlic from basement to fridge late September-late Oct as needed to make room for winter squash.
Weeding: this is a good catch up time on weeding in the raised beds.
4th fall disking and seeding: Sow cover crops wherever possible (in unused raised beds too). The last chance for oats is early Sept (9/15??). Can sow winter wheat (winter-killed in zone 4) or winter barley (dies in zone 6) if oat planting date missed. (Oats winter-kill in zone 8). Can sow hardy Austrian winter peas in late Sept at 8oz/100sq.ft. with rye. Can sow red clover this month.
Bush-hog late corn if undersown with oats and soy cover crop.
Perennials: New strawberry beds: Prepare and plant by mid-September if not done in late August. Weed strawberries. Could till up grass in grape alley & sow clover if not done in March. If clover sown earlier, let it seed.
Harvest and store winter squash: Acorn (pepo) types (stem still green, ground spot “earthy” or orange), store 1-4 months; Maximas: Cha Cha, Jarrahdale, Kabocha (stem 75% corky) store 3-5 months; Moschatas: Butternuts, Cheese (peanut colored skin, no mottling or streaks) store 4-8 months, or more. Leave on live vines as long as possible, avoiding frost on fruits. Cut leaving long stem using pruners; handle gently.
September Harvests: Asian melons, asparagus beans, beans, beets and beet greens, broccoli, cabbage, cantaloupes, carrots, cauliflower, celery, chard, Chinese cabbage, corn, cow peas, cukes, edamame, eggplant, horseradish,leeks, lettuce, limas, maruba santoh, okra, pak choy, peppers, hot peppers,radishes, Romas, scallions, senposai, summer squash, Tokyo bekana, tomatoes, turnips, watermelons, winter squash, yukina savoy, zucchini. It is possible to lightly harvest rhubarb during September, if wanted.
It can be hard to find out just how cold a temperature various vegetable plants can survive. Reading books written in different parts of the country can be confusing: “survives all winter” is one thing in the Pacific Northwest and another in Montana. So for some years I have been collecting data and exchanging information with my friend and neighbor Ken Bezilla at Southern Exposure Seed Exchange. Each winter I try to record what dies at what temperature. Below is my current list, which should be treated as a work in progress.
Your own experience with your soils, microclimates and rain levels may lead you to use different temperatures. If you have data from your garden, please leave a comment. Likewise if you have found particular varieties to be especially cold-tolerant, I’d love to learn more. Central Virginia isn’t the coldest spot in the US, but if I can grow something without rowcover, I’m happy to hear it!
Here’s our temperature list at which various crops die:
35°F (2°C): Basil.
32°F (0°C): Bush beans, 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): Most cabbage, Sugarloaf chicory (takes only light frosts), radicchio.
25°F (-4°C): Broccoli heads, chervil, chicory roots for chicons, and hearts, probably Chinese Napa cabbage (Blues), dill, endive (hardier than lettuce, Escarole more frost-hardy than Frisée), annual fennel, large leaves of lettuce (protected hearts and small plants will survive even colder temperatures), some mustards and oriental greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), onion scallions, radicchio. Also white mustard cover crop.
22°F (-6°C): Arugula, Tatsoi. (both may survive colder than this.) Possibly Chinese Napa cabbage (Blues), Maruba Santoh, Mizuna, Pak Choy, Tokyo Bekana with rowcover.
20°F (-7°C): Some beets, cabbage heads (the insides may still be good even if the outer leaves are damaged), celeriac, celtuce (stem lettuce), some corn salad, perhaps fennel, some unprotected lettuce – some OK to 16°F (-16 °C), some mustards/oriental greens (Tendergreen, Tyfon Holland greens), radishes, turnips with mulch to protect them, (Noir d’Hiver is the most cold-tolerant variety).
17°F (-8°C): Barley (cover crop)
15°F (-9.5°C): Some beets (Albina Verduna, Lutz Winterkeeper), beet leaves, broccoli leaves, young cabbage, celery (Ventura) with rowcover (some inner leaves may survive at lower than this), cilantro, endive, fava beans (Aquadulce Claudia), garlic tops may be damaged but not killed, Russian kales, kohlrabi, perhaps Komatsuna, some covered lettuce, especially small and medium-sized plants (Marvel of FourSeasons, Rouge d’Hiver, Winter Density), curly leaf parsley, flat leaf parsley, oriental winter radish with mulch for protection (including daikon), large leaves of broad leaf sorrel, turnip leaves, winter cress.
12°F (-11°C): Some cabbage (January King, Savoy types), carrots (Danvers, Oxheart), multi-colored chard, most collards, some fava beans (not the best flavored ones), garlic tops if fairly large, most fall or summer varieties of leeks (Lincoln, King Richard), most covered lettuce (Freckles, Hyper Red Rumpled Wave, Parris Island, Tango) , large tops of potato onions, Senposai, some turnips (Purple Top).
10°F (-12°C): Beets with rowcover, Purple Sprouting broccoli for spring harvest, Brussels sprouts, chard (green chard is hardier than multi-colored types), mature cabbage, some collards (Morris Heading), Belle Isle upland cress, some endive (Perfect, President), young stalks of Bronze fennel, perhaps Komatsuna, some leeks (American Flag), Oriental winter radish, (including daikon), rutabagas, (if mulched), tops of shallots, large leaves of savoyed spinach (more hardy than flat leafed varieties), tatsoi, Yukina Savoy. Also oats cover crop.
5°F (-15°C): Garlic tops if still small, some kale (Winterbor, Westland Winter), some leeks (Bulgarian Giant, Laura, Tadorna), some bulb onions (Walla Walla), potato onions and other multiplier onions, smaller leaves of savoyed spinach and broad leaf sorrel.
0°F (-18°C): Chives, some collards (Blue Max, Winner), corn salad, garlic, horseradish, Jerusalem artichokes, Vates kale (although some leaves may be too damaged to use), Even’ Star Ice-Bred Smooth Leaf kale, a few leeks (Alaska, Durabel); some onion scallions (Evergreen Winter Hardy White, White Lisbon), parsnips, salad burnet, salsify, some spinach (Bloomsdale Savoy, Olympia, Tyee). Also small-seeded cover crop fava beans.
Even Colder: Overwintering varieties of cauliflower are hardy down to -5°F (-19°C).