Winter-Kill Temperatures of Cold-Hardy Vegetables 2020

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

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

Winter-Kill Temperatures of Cold-Hardy Vegetables 2020

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

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

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

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

My other results from other years still hold up.

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

Radicchio seeds from Seeds from Italy

Notes on Chicories and Endives

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

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

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

Using the List

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

Hoophouse beds in November.
Photo Ethan Hirsh

Hoophouse Notes

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

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

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

Young Bright Lights chard.
Photo Pam Dawling

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

Outdoor killing temperatures of crops (unprotected unless stated)

35°F (2°C):  Basil.

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

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

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

Tokyo bekana in our hoophouse.
Photo Twin Oaks Community

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

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

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

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

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

Young Cylindra beets.
Photo Wren VIle

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

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

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

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

Garlic shoots in January.
Photo Pam Dawling

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

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

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

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

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

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

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

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

Cooking Greens in March

 

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

Cooking Greens to Harvest in Central Virginia in March

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

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

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

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

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

Cooking Greens to Sow in Central Virginia in March

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

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

Winstrip tray with chard seeds.
Photo Pam Dawling

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

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

Cooking Greens to Transplant in Central Virginia in March

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

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

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

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

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

Other Cooking Greens Tasks in Central Virginia in March

Open flat of broccoli seedlings.
Photo Wren Vile

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

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

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

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

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

Hoophouse transition to give an extra month of greens.

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

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

Cooking Greens in February

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

Cooking Greens to Harvest in Central Virginia in February

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

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

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

Bolting Golden Frills and Scarlet Frills.
Photo Pam Dawling

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

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

Hoophouse turnips have delicious greens too!
Photo Wren Vile

Cooking Greens to Sow in Central Virginia in February

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

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

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

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

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

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

Cooking Greens to Transplant in Central Virginia in February

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

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

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

Other Cooking Greens Tasks in Central Virginia in February

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

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

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

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

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

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

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

Special Cooking Greens Topic for February:

Planning our Field Planting Schedule.

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

Field Planting Schedule:

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

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

 

Hoophouse Musings, Bugs, Okra, Edible Landscaping Workshops in Maryland

Hoophouse beds in December. This is why we have a hoophouse!
Photo Wren Vile

Winter hoophouse posts in Mother Earth News newsletter

Sowing and Transplanting Winter Crops in a Hoophouse

Grow Great Lettuce in Winter

Winter hoophouse lettuce
Photo Kathryn Simmons

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A photo of a Tiny House from Wikipedia

Would you live in a hoophouse?

A reader wrote in:

“I have actually been thinking of building a tiny house and putting it inside a big hoophouse, creating a living area that would include a yard, trees, and gardens – allowing me to snowbird in place in northern New England – but I’m concerned about outgassing, since I’d be there almost 24-7 most days (I work out of my home). Have you done any research on outgassing of hoophouses?”

A Tiny House is generally a residential structure under 400 sq. ft

First off, No I haven’t done any research about hoophouse off-gassing, but I wouldn’t worry about out-gassing from the polyethylene of the hoophouse. Other products  are much closer to your nose: All the materials used to construct, preserve and decorate the house and all the products within the house, such as furniture,  fabrics, soaps, appliances etc.

There are some other things I’d wonder about:

1.      Temperature. When the sun shines, the interior of the hoophouse warms up. When the sun doesn’t shine, it doesn’t. Would you heat the tiny house? You’d have to avoid heating systems that could damage the plants.

2.      Snowfall. When it snows, you need to remove the snow from the roof of the hoophouse. Some snow can be carefully pulled down from the outside. Usually we also walk around inside the hoophouse bouncing a broom on the inside of the plastic to move the snow off. You can’t do that if you have a house in the way.

3.      Humidity. In the winter we grow cold-tolerant hoophouse crops. We are aiming for 65 F (18C). We need fresh air for the plants and to deter fungal diseases. It doesn’t work to keep the hoophouse sealed up and “cozy”!

4.      Strong winds. In hurricanes and gales, hoophouses sometimes collapse or get destroyed. You don’t want to be inside when that happens.

5.      Height. Our hoophouse is less than 14 ft (4 m) at the apex.

In conclusion I’d say it’s better to have a small patio seating area within your hoophouse for suitable sunny days, rather than plan to live inside all the time.
Brassicas in a nematode-fighting hoophouse crop rotation in Hawaii.
Credit Gerry Ross, Kupa’a Farms

Do you value crop rotation in your hoophouse?

A reader in the Pacific Northwest wrote: “This winter I have been re-thinking my crop rotation plan after having some issues (with flea beetle larvae in the soil outsmarting my diligent insect netting of my brassica salad crops). These days I see intensive market gardeners seeming to not worry so much about rotation (i.e. Neversink farm, etc), and yet I’ve always been taught that it is such an important principle to follow. I reviewed your slideshows on crop rotation and also cool crop planning in the greenhouse (which briefly addresses salad brassica rotation with other crops). With how much space I have and the high demand I have for brassicas, for salad mix (mustards) and also the more mainstay cole crops, I had settled on a 2.5 yr between brassica crop rotation (but planting two successions of mustards in the same bed within one year, in the year the bed was in mustards, with a lettuce or other crop breaking up the successions, with the idea that they were very short day and also light feeder crops). Wondering if you think this just doesn’t sound cautious enough, or if this sounds like a reasonable compromise with not having more space to work with (and wanting to satisfy the market demand for brassicas).”

I replied: “Yes, I do think crop rotation is important. I do know some farms seem to have given it up. I think what you are seeing shows one reason why rotation is important. In our hoophouse, we do as you do, allocating brassicas to a space for that winter season and perhaps doing more than one round of brassica crops. Then moving away from brassicas for the next two winters. If doing that doesn’t get rid of the flea beetle problem, and you are being thorough about netting with small-enough mesh netting (sounds like you are, but maybe check the mesh size), then my next step would be spinosad when the flea beetles appear. You can spray the inside of the netting too, and close it quickly. It’s that or a longer rotation, which it sounds like is not financially viable. You could also try farmscaping and/or importing predatory insects (not sure if there are any), Are there beneficial nematodes that attack flea beetle larvae? These are things I don’t know about, but might be worth looking into.”

 

Late sweet corn and sweet potatoes
Credit Ezra Freeman

Sweet Potato fends off bugs

Modern Farmer has this fascinating article about sweet potato plants alerting their neighbors to pest attacks.

Researchers from the Max Planck Institute and the National Taiwan University found that when sweet potato plants are attacked by insects, they emit a bouquet of odors and start production of a protein called sporamin that makes them unappetizing. Neighboring sweet potatoes sense the odors and start their own production of sporamin.


 

A new Tokyo bekana transplant attacked by vegetable weevil larvae October 10
Photo Pam Dawling

Insect damage cause stress-response production of anti-oxidants

In a related piece of news, Agrilife Today from Texas A&M AgriLife Research has found some evidence that wounded plants produce anti-oxidants as a stress response, which may make them healthier for human consumption. Read the report here.

Edible Landscaping with a Permaculture Twist Spring Series

Michael Judd in cooperation with Common Market CO+OP is presenting a combination of hands-on workshops at Long Creek Homestead and evening talks at the Common Market, Frederick Maryland.

Click here for info on Spring Workshops/Talks/Tours

·        Inoculating Mushrooms

·        Fruit Tree Grafting

·        Herb Spirals

·        Creating Growing Beds- Swales and Hugelkultur

·        Edible Landscaping & Straw Bale Home Tour

·  For the Love of PawPaws


 

Fire Ants have reached Toronto

A reader wrote in that the European Fire Ant is now found in Toronto.


“There were two nests of these in my allotment garden 2018.
They actually moved the nest in order to be closer to the zucchini
plants.  Hand on heart: I never had  any cucumber beetles develop past
the instar stage.  The ants did not eat the eggs but they ate the larvae
as soon as they hatched.  Same for potato beetle.  My neighbours had
the best cucumber harvest in history. 
What I’ve read is these Fire Ants kill colonies of native ants.  Summer 2019 I had a Pavement Ant war that went on for days.  Clearly the Fire Ants did not wipe them out.  There are black ants and other smaller red ants
in my garden.  The Fire Ants appear to have moved on for some reason known
only to themselves.   Perhaps they too have enemies.”
“There’s a guy with a Youtube channel who keeps ant colonies.   AntsCanada although he is in the Philippines.  What happened was the feral Pharaoh Ants invaded his colony of Fire ants and killed them.  Pharaoh Ants are much smaller but perhaps that’s what gave them the advantage.   We have Pharaoh ants in Toronto also.   I spend a lot of my time looking at the little critters in my garden.  Like red velvet mites:  there were many in 2016.  Have not seen a single one in two years now. “

Video of Okra Taste Testing

Chris Smith, author of The Whole Okra

Chris Smith, author of  The Whole Okra: Chris has a video of
the taste testing on  Youtube, https://www.youtube.com/watch?v=sAy0pouxlME

Cooking Greens in January

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

Cooking Greens to Harvest in Central Virginia in January

Harvest in time! Freezing or Bolting Greens!

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

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

Tatsoi in our hoophouse in December.
Photo Kathleen Slattery

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

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

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

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

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

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

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

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

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

Transplanting spinach from a Speedling flat.
Photo Denny Ray McElya

Cooking Greens to Sow in Central Virginia in January

Outdoors, we sow nothing.

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

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

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

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

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

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

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

Follow-on Winter Hoophouse Crops

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

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

Cooking Greens to Transplant in Central Virginia in January

Outdoors, we transplant nothing.

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

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

Other Cooking Greens Tasks in Central Virginia in January

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

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

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

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

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

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

Special Cooking Greens Topic for January: Lots of Planning!

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

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

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

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

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

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

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

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

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

Hoophouse video interview, plus 2019 Round up of favorite topics and posts you missed

No-Till Growers and Josh Sattin collaborated to post this Hoophouse Tips video interview of me talking about our hoophouse:

 

After a Best Ever day on November 7, 2019, when 876 people viewed my website (4,855 that week), December has been quiet. It’s not a big gardening month for most of us, and the month is full of holidays. And then there’s the urge to hibernate.

Nonetheless, I have been reliably posting every week, and you might have accidentally missed something, while entertaining the visiting aunts and uncles, or rushing to get the carrots harvested, or something involving food and drink. Here’s a chance to  find the lost treasures!

December 24, I posted a Book Review: Grow Your Soil! by Diane Miessler

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Three potato forks to the left, four digging forks to the right.
Pam Dawling

On December 18, I posted Making Use of Greenhouse Space in Winter and Getting the Right Fork

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Purple ube grown in North Carolina by Yanna Fishman

December 10, did you miss Yanna Fisher’s splendid purple ube?

And Josh Sattin’s video interview with me? Legendary Farmer on a Legendary Commune  https://youtu.be/vLzFd4YP9dI

And Jesse Frost’s interview with me on his podcast No-Till Growers ?  You can listen to it here and it’s also on You Tube: https://www.youtube.com/watch?v=p75gRIl0Hzs


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

On December 3, I posted Cooking Greens in December

———————————————————–

On November 26, I offered you a Book Review: Will Bonsall’s Essential Guide to Radical, Self-Reliant Gardening


My Top Six. no Seven,  posts of all time:

Winter-kill Temperatures  of Winter-hardy Vegetables 2016 with 23,776 views, peaking in November. Clearly lots of people want to know which crops will survive and which to hurry and harvest, or protect with rowcover.

Garlic scapes with 11,202 views. Garlic and sweet potatoes are the favorite crops on this site. Garlic scapes used to be under-appreciated and under-used. Not now!

Winter-kill Temperatures of Cold-Hardy Vegetables 2018 with 9,979, also peaking in November. My list gets updated each year as I learn new information. But the older ones come higher on internet searches.

Soil Tests and High Phosphorus Levels close behind at 9,503. High phosphorus is a worry for organic growers, especially those using lots of compost, as it can build up each year.

How to Deal with Green Potatoes at 8,613, with sustained interest through August, September and November. Obviously we are not the only growers with this problem, caused by light getting to the tubers.

Tokyo Bekana at 2,199 (who knew that was so popular?)

In 2019 other popular posts included Hunting Hornworms and the newer Winter-Kill Temperatures of Cold-Hardy Vegetables 2019. It takes a while for newer posts to gain on the older favorites.

Cooking Greens in November

A cabbage, with curled back leaf on the head, showing maturity.
Photo Bridget Aleshire

Cooking Greens to Harvest in Central Virginia in November

Beet greens – we get our last chance for greens as we harvest all our beets for storage. Sometimes the greens are in too poor shape to eat. Beets are hardy down to 15-20°F (–7 to –9.5°C) outside without rowcover.

There’s also cabbage, chard, Chinese cabbage (perhaps), collards, kale, komatsuna, senposai, , spinach, tatsoi, and Yukina savoy. Eat-All Greens harvests can continue, if you sowed some in September. When we sowed some on September 16, we got several harvests in November.

From the hoophouse we continue harvesting spinach, tatsoi thinnings and leaves, as well as leaves of Tokyo Bekana and Maruba Santoh. We can start to harvest chard, senposai, Yukina Savoy leaves and perhaps kale, although it is a slow grower.

At the end of November we keep a close eye on the Tokyo Bekana and Maruba Santoh, for signs of bolting. Normally these will bolt in December, so we harvest the whole plants that month. But we have sometimes needed to terminate the plants November 26 or so.

Cooking Greens to Sow in Central Virginia in November

Young spinach plants (and henbit) in our hoophouse in December.
Photo Pam Dawling

Outdoors

we sow spinach (for spring harvesting) in early November if we have not been able to do it already.  Hopefully we will have got this done during October. Here it’s too late for any more outdoor sowings till spring, although there will be garlic planting.

In the hoophouse

on November 9 we sow spinach #3 to fill any spinach casualties that happen during the winter, and “Frills“ #2 (mizuna, Ruby Streaks, Scarlet Frills, Golden Frills). This is one of our favorite winter crops to suppress nematodes. We sow tatsoi #2 on November 15. We could sow Eat-All Greens in hoophouse in November, but so far we haven’t tried that.

No Cooking Greens to Transplant in Central Virginia in November!

Other Cooking Greens Tasks in Central Virginia in November

While watching the temperature forecasts, we continue to harvest the hardier greens, such as chard, yukina savoy, collards, kale, spinach and tatsoi.

Pak Choy outdoors should be harvested before night temperatures of 25°F (–4°C) or covered with thick rowcover.
Photo Ethan Hirsh

As night temperatures drop, we clear some crops

In this order:

25°F (–4°C) Most broccoli, some cabbage, Chinese Napa cabbage, Maruba Santoh, mizuna, most pak choy, Tokyo Bekana.

22°F (–6°C): Bright Lights chard.

20°F (–7°C): Less-hardy beets, broccoli heads (some may be OK to 15°F/-9°C), Brussels sprouts, some cabbages (the insides may still be good even if the outer leaves are damaged),  cauliflower, most turnips.

15°F (–9.5°C): The more hardy beet varieties and their greens, some broccoli, some cabbage, red chard (green chard is hardy to 12°F (-11°C)),  Russian kales, rutabagas if not covered, turnip leaves, most covered turnips.

Each winter I update my Winter-kill Temperatures of Cold-Hardy Vegetables. This year I’m watching the Koji carefully, to get some good data.

Washing Cylindra beets for storage.
Photo Wren Vile

Killing temperatures outdoors

Here are some more numbers for killing temperatures outdoors (without rowcover unless otherwise stated). In my Cooking Greens in October post, I gave the Veggie Deaths in the  35°F (2°C) to 15°F (–9.5°C) range. Here’s the next installment, which I am prompted to post by the forecast 16°F (-9°C) here for the night of Friday November 8. This list only includes the cooking greens. Your results may vary!  Let me know!  Click the link above to see the complete list.

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

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

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

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

 Reminder: The temperatures given are air temperatures that kill those outdoor unprotected crops.

Ruby chard.
Photo Kathryn Simmons

Overwintering chard

To keep chard in good condition overwinter, either cover with hoops and rowcover (in milder areas, Zone 6 or warmer), or else mulch heavily right over the top of the plant, after cutting off the leaves in early winter.

Covering spinach

Once the frost has killed the galinsoga we go ahead and put rowcover over the spinach beds. That happened this weekend (November 2 and 3) – we got temperatures of 27°F (–3°C) and 25°F (–4°C). Spinach will make growth whenever the temperature is 40°F (5°C) or more, which happens a lot more often under rowcover than exposed to the elements. We don’t want to provide rowcover for the galinsoga!

Weeding rowcovered spinach in winter.
Photo Wren Vile

Special Cooking Greens Topic for November: Seed Inventory

November is a good month for us to start our big winter planning process. For all the crops, not just cooking greens! The first step is the Seed Inventory, in preparation for ordering the right amounts of the right varieties of seeds for next year. We do ours fairly accurately, because we also use the process to fine tune the amount of seed  to buy for each row we plan to sow. Some growers simply buy plenty and throw away all the leftover seed each season, but for us the time spent paying attention to what we need is very worthwhile. See the Planning section in my book Sustainable Market Farming for step by step details on how we do it.

We use a spreadsheet and a cheap little digital scale (for the small amounts, up to 100g). Ours is an AWS-100. It’s not legal for trade, but we are not using it to weigh seeds for sale, just to give ourselves a good idea of what we have left. For large quantities, we use our business shipping scale.

We take a few seed buckets and the scale into a pleasant-temperature room, and take out a bundle of seed packets of a particular crop. First we weigh a packet at a time and write down the amount. The scale can be tared for the empty packet.

Seed Viability

Next we assess whether the seed will be viable next year. Storage conditions make a big difference, the best storage being cool, dark, dry and airtight. Make your own decisions based on 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.

We have a simplified chart:

  • Year of purchase only: parsnips, parsley, salsify, scorzonera and the even rarer sea kale;
  • 2 years: corn, peas and beans of all kinds, onions, chives, okra, dandelion and
    martynia;
  • 3 years: carrots, leeks, asparagus, turnips and rutabagas;
  • 4 years: spinach, peppers, chard, pumpkins, squash, watermelons, basil, artichokes and cardoons;
  • 5 years: most brassicas, beets, tomatoes, eggplant, cucumbers, muskmelons, celery, celeriac, lettuce, endive and chicory.

If the seed is still recent enough to grow well, we keep it. If it is too doubtful we “write it off” on the spreadsheet and consign the packet to a special “Old Seeds” bucket, which we keep for a year in case of mistakes or desperation!

This is the time we adjust the “seed rate” (seed/100′ or /30 m) column on our spreadsheet using our new information from our year.

After completing the inventory we have our annual Crop Review which we combine with popping garlic cloves for planting.

Popping garlic cloves in preparation for planting
Photo credit Southern Exposure Seed Exhcange

Hoophouse Sliding Doors, Vegetable Weevil Larvae – Seasonal Challenges!

September 6 sowing of tatsoi and our August 28 sown catch crop of Tokyo bekana. We harvested the last of this catch crop October 14 and sowed turnips, Photo Pam Dawling

October is the busiest month in our hoophouse! The bed prep, sowing and transplanting keeps us busy for 3 or 4 hours a day. Add in harvesting (peppers, radishes, salad crops) and hand-watering of new plants, and we’re there for a good half of each day. And then there are extra challenges. Yesterday, in tightening one of the strings that mark the bed edges, I managed to hammer a 6” sod staple right through the irrigation main line tubing, which was below soil level. I can hardly believe I did that! I even thought “Be careful not to stab the water pipe!” So I had to dig it up, find a coupler and fix it right away. Because at this time of year, we rely on the irrigation for all the new plants.

And the nights are getting colder. We intend to close the doors every night when the temperature will be below 50F (10C), and the windows if the temperatures will be below 45F (7C). We have been converting the doors at one end from hinged to sliding doors. They’re hanging on their tracks, but one door is jamming in the track, and we need more than a cursory look to fix the problem. So meanwhile, only 3 of the 4 doors close!

One of the new sliding doors on our hoophouse.
Photo Pam Dawling

Hoophouse Doors

My book The Year Round Hoophouse, has a chapter on making end walls, including doors and windows. Writing that helped me decide to change our east doors. Here’s an excerpt from that chapter:

 “For our 30′ (9.1 m) wide gothic hoophouse, we have a pair of hinged double 4′ x 8′ (1.2 x 2.4 m) doors at each end. Our doors open out and have to drag over the grass outside. We have found “rising butt” hinges to be helpful here. As the door opens, it rises on the curved base of the hinge, giving a little extra clearance above the ground. Each door fastens with a hook and eye to the wall when open (it will get windy!).  I recommend considering sliding doors, with the track and hardware on the inside, if the tunnel is wide enough for the track needed to carry the size of doors wanted. This avoids problems in many weathers: rampant grass-growing season, snow season, strong winds. Some people purchase storm doors and use those, but they are not very big. Anyone with basic carpentry skills can make simple door and window frames, as they will be covered both sides in lightweight plastic and not need to be extremely strong.”

View through the old hinged hoophouse doors in a previous December.
Photo Kathleen Slattery
Close up of a roller bracket attaching our hoophouse door to the track.
Photo Pam Dawling
  •  Matt Kleinhenz of the Ohio State University Vegetable Production Systems Laboratory, has a slide show of end wall designs High tunnel end wall and door types images,
  • ·        David Laferney of The Door Garden, in Building Greenhouse Doors,, 2008 has clear photos of hinged door construction for beginner carpenters.
  • ·        Hightunnels.org has various articles on construction, including a slideshow Images of High Tunnel Doors.
  • ·        For more to read, see M D Orzolek, High Tunnel Production Manual. See Chapter 3: High Tunnel Construction

Vegetable Weevil Larvae

A new Tokyo bekana transplant attacked by vegetable weevil larvae October 10
Photo Pam Dawling

Sometimes in the cool weather we have problems with this secretive pest chewing holes in brassica leaves at night. The larvae live in the soil and stay underground or deep in the heart of the plants during the day, so if your leaves are holey, but you can’t find any culprits, you can suspect vegetable weevil larvae. They especially like turnips, pak choy and the flavorful mustardy greens. We sprayed with Spinosad last Monday, then again on Friday, and this week (Monday and Tuesday) I’m not seeing any new holes.

Debbie Roos of Growing Small Farms wrote about this pest in “The Bok Choi Problem” which has good photos and a Description and Biology of the Vegetable Weevil

Vegetable weevil larvae in action. From Growing Small Farms
Photo Debbie Roos

 

Cooking Greens in October

 

Vates kale in the fall.
Photo Bridget Aleshire

Cooking Greens to Harvest in Central Virginia in October

Beet greens, broccoli, cauliflower, cabbage, chard, Chinese cabbage, collards, kale,  komatsuna, Maruba Santoh, pak choy, senposai, spinach, tatsoi, Tokyo Bekana turnip greens and Yukina savoy can be available here all month (and perhaps longer, depending on the temperature). OP Yukina Savoy seems more cold-hardy  and bolt-resistant than the hybrid Koji.

The new outdoor greens this month are tatsoi, kale, spinach, collards, and mizuna (if we have that outdoors).

Eat-All Greens harvests can start, if you sowed some last month. When we sowed some on September 16, we got two harvests in October and several in November.

From the hoophouse we start to harvest spinach, tatsoi, and leaves of Tokyo bekana.

Cooking Greens to Sow in Central Virginia in October

This month we finish sowing spinach and kale for overwintering outdoors (10/30 is our last chance). No more outdoor sowings until spring!

“Filler Greens”

Filler greens: short rows of Tokyo bekana, Yukina Savoy and senposai used to fill gaps in the winter hoophouse.
Photo Pam Dawling

On October 10, we sow Brassica fillers #1. These are short rows of senposai, Tokyo bekana, Yukina Savoy, Maruba Santoh,  to use to fill gaps later during the winter as soon as they occur. We simply dig them up, replant where needed and water well. Alternatively you could keep some plug flats of these plants handy. Bare-root transplanting is much easier than many fear.

During December we use the “Filler” greens plants to replace casualties and harvested heads of Tokyo bekana, Maruba Santoh, Chinese cabbage, Pak choy, Yukina Savoy and tatsoi daily. We stop filling gaps in these early harvest crops on December 25, as they will bolt in the hoophouse conditions in January at the latest.

We continue to fill gaps elsewhere with senposai until January 25. Asian greens don’t make good growth before bolting if transplanted after January 25. From January 25 to February 20 we fill all gaps everywhere with spinach transplants

Hoophouse Bed preparation and Planting

In the hoophouse we have a lot of bed preparation (all the beds except the Early Bed which we plant in September), as well as transplanting and sowing.

On October 14, we sow turnips #1: Red Round (1 row on North), Hakurei (2 rows South). Oasis, White Egg.

On October 20, we sow Filler Greens #2.

By October 23, we clear and prepare two more beds and sow spinach #2; tatsoi #2, turnips #2, chard #2 and perhaps Frills (Frilly Mustards) #1.5.

Brassica (Mustard) Salad Mix

Interesting mustard mixes are sold for salad mixes. We often mix our own Brassica Salad Mix from leftover random brassica seeds. For a single cut, almost all brassicas are suitable – just avoid turnips and radishes with prickly leaves! We sow between October 2 and November 14 for harvests during the winter, and from December 4 to February 12 for March and early April harvests.

We could, but so far we haven’t, sow Eat-All Greens in hoophouse in October.

Catch crops

Useful if a crop fails, or you have an empty space. Don’t delay, as rates of growth slow down as the temperatures and daylight decrease. Don’t expect much from sowings during the Persephone Days (less than 10 hours daylight).

Tokyo bekana is a quick-growing Asian green, for cooking or salads.
Photo Twin oaks Community

This year we grew an early catch crop of Tokyo bekana when we realized we had space that wouldn’t be needed till mid-October (for turnips). We direct sowed it August 28, weeded and thinned to 1” (2.5 cm) on September 5; weeded and thinned to 3” (7.5 cm) on September 16, using the small plants for salad. We need to clear this crop by the middle of October to sow the turnips, and the Tokyo bekana has got to a fine size.

  • Ready in 30–35 days in fall, longer in winter: brassica salad mixes, spinach, chard, salad greens (lettuce, endives, chicories), winter purslane., kale, arugula, radishes (the fast small ones and the larger winter ones), many Asian greens: Komatsuna, Maruba Santoh, mizuna, frilly mustards, Senposai, tatsoi, Tokyo Bekana and Yukina Savoy.
  • Ready in 35–45 days in fall: corn salad, land cress, sorrel, parsley and chervil.
  • Ready in 60 days in fall: beets, collards, kohlrabi, turnips

Cooking Greens to Transplant in Central Virginia in October

September sown White Russian kale (transplanted in October).
Photo Wren Vile

In our hoophouse in early October, we transplant Tokyo Bekana, Chinese cabbage, Pak choy, Yukina savoy #1,  using plants which we sowed outside under insect netting.

By October 13, we transplant chard #1, Frills #1, and Red and White Russian kales, from our outdoor nursery seedbed.

By October 21, we clear and prepare another bed and transplant 1/2 bed kale, plus Yukina Savoy, and frilly mustards. (This is our favorite crop selection to suppress nematodes),

By October 23, we clear and prepare two more beds and transplant senposai and Yukina Savoy #2 from the outdoor nursery bed.

Other Cooking Greens Tasks in Central Virginia in October

October is our month to weed and thin the fall crops in the outdoor raised beds, especially spinach and kale. We thin kale to 12” (30 cm); perhaps more space would be better, although Vates is a dwarf variety.

We put rowcover over any beds of pak choy, Chinese cabbage or Tokyo bekana we have that year. Later we weed (again!) and cover the spinach for faster growth, but leave the kale uncovered after a bad experience of Vates kale with rowcover fibers mixed in. The cooks didn’t love us!

Galinsoga dies with the frost.
Photo Wren Vile

We prefer to wait to cover spinach after frosts kill the galinsoga. As well as raised beds, we plant spinach in our cold frames, making good use of the space until the frames are needed in spring for hardening off transplants.

We roll, label and store drip tape from the fall broccoli and cabbage

Special Cooking Greens Topic for October: Get Soil Tests; Be Ready for Cold Nights.

October is a good month to do soil tests, when the soil is not too wet, and the soil temperatures are still warm (the soil life is active).

Weather Forecasting

We use Wunderground, but subtract 5F° from their forecast night lows for our nearest town, and mentally downgrade the chance of rain by 10%, as rain often passes us by as it scoots along the river valley north of us.

See Weatherspark.com for the typical ranges of weather in your area:

Savoy cabbage with frost.
Photo Lori Katz

Predicting Frost

Frost is more likely at Twin Oaks if:

  • The date is after 10/14 or before 4/30 (our average first and last frost dates).
  • The Wunderground forecast low for Louisa Northside is 37°F (3°C) or less.
  • The daytime high temperature was less than 70°F (21°C).
  • The temperature at sunset is less than 50°F (10°C).
  • The sky is clear.
  • The soil is dry and cool.
  • The moon is full or new (maybe to do with tides and gravity?).
  • If temperatures are falling fast, the wind is from NW and the sky is clear, then polar air may be moving in, and we’ll get a hard freeze.
  • The dew point forecast is low, close to freezing. Frost is unlikely if the dew point is 43°F or more.

Watch for cold night temperatures and decide which crops to harvest, which to cover, which to abandon:

In a double-layer hoophouse (8F/5C warmer than outside) plants can survive 14F/8C colder than outside, without extra rowcover; with thick rowcover (1.25 ozTypar/Xavan) plants can survive at least 21F/12C colder than outside.

The hoophouse winter crops are an important part of feeding ourselves year-round

Each winter I update my Winter-kill Temperatures of Cold-Hardy Vegetables.

Here are some early winter numbers for killing temperatures outdoors (without rowcover unless otherwise stated). Your results may vary!  Let me know!        

35°F (2°C): Basil.

32°F (0°C): Beans, cucumbers, eggplant, melons, okra, peppers, tomatoes.

27°F (–3°C): Many cabbage, Sugarloaf chicory.

25°F (–4°C): Some cabbage, chervil, chicory roots for chicons and hearts, Chinese Napa cabbage, dill, endive, some fava beans, annual fennel, some Asian greens (Maruba Santoh, mizuna, most pak choy, Tokyo Bekana), some onion scallions (many varieties are hardier), radicchio.

22°F (–6°C): Some arugula (some varieties are hardier), Bright Lights chard, large leaves of lettuce (protected hearts and small plants will survive colder temperatures), rhubarb stems.

20°F (–7°C): Some beets, broccoli heads (some may be OK to 15°F/-9°C), Brussels sprouts, some cabbages (the insides may still be good even if the outer leaves are damaged), celeriac, celtuce (stem lettuce), some head lettuce, some mustards/Asian greens, flat leaf parsley (curly parsley is hardier), radishes, most turnips.

15°F (–9.5°C): Some beets, beet greens, some broccoli, some cabbage, rowcovered celery, red chard (green chard is hardy to 12°F (-11°C)), cilantro, endive, some fava beans, Russian kales, kohlrabi, some lettuce, especially medium-sized plants with 4-10 leaves, curly parsley, rutabagas if not covered, broad leaf sorrel, turnip leaves, most covered turnips, winter cress.

Frosted daikon radish.
Photo Bridget Aleshire

Frilly Mustards in our Winter Hoophouse

 

Hoophouse frilly mustard, mizuna and lettuce mix in our hoophouse in December.
Photo by Kathleen Slattery

I have written before about our love of Ruby Streaks, a beautiful dark red frilly mustard. We also like Golden Frills and Scarlet Frills. We like Mizuna too. It was our “gateway frilly mustard”!

Green mizuna in our hoophouse in November.
Photo Pam Dawling

Mizuna – the Gateway Mustard.

Mizuna is a very mild flavored crop, with thin juicy white stems and green ferny leaves which add loft in salad mixes. (“Loft” is the word for the “puffiness” of frilled salad crops, helping them occupy space and not collapse in the bottom of the bag or bowl like wet green corn flakes.) This tolerant crop is very easy to grow, tolerates cold wet soil, and variable weather. It is fairly heat tolerant (well, warm tolerant), and cold tolerant to 25°F (-4°C).

We used to just grow just one planting, sowing it outdoors September 24, transplanting it into our hoophouse October 22. It regrows vigorously after cutting and we harvest leaves from November 27 to January 25 or even to March 7, when it becomes a mass of small yellow flowers (edible!). In the winter, once the plant gets bigger and bushier, we switch from harvesting individual leaves to a method we call the “half-buzz-cut.” We gather the leaves on one side of the plant and cut them with scissors about an inch above the soil. Then we chop them into our salad mix harvest bucket. The plants look odd with half their leaves still full-size and half shorn, but this method seems to help the plant regrow quicker. The big leaves can photosynthesize and feed the regrowing leaves.

Next we tried Purple Mizuna, but we were disappointed with the weak color and a constitution less-robust than green mizuna.

Ruby Streaks and other Frilly Mustards

After a few years of growing mizuna, we discovered Ruby Streaks. It has a much stronger color, and I admit, a much stronger flavor. Our diners don’t generally like pungent greens, but this one, cut small and mixed with other salad greens, gained wide approval. We have moved on to include Golden Frills and Scarlet Frills, and for a while Red Rain. We find the Scarlet Frills and Golden Frills bolt (go to seed) later than Ruby Streaks and Mizuna.

Ruby Streaks beside green mizuna.
Credit Ethan Hirsh

Adding a Second Sowing

We added a second sowing, this one direct-sown in the hoophouse, on October 30, and the next year shifted the date to November 9. These direct-sown mustards can be used for baby salads after only 21 days (when thinning the rows, for instance). Thin to 8″–12″ (20–30 cm) apart, to grow to maturity in 40 days. We sow mizuna and the spicier mustards at the same time, usually 6 rows to a 4’ (1.2 m) wide bed, maybe a total row length of 50’ (15 m). This sowing gives us harvests from February 26 to March 24, several weeks later than the September 24 sowing.

Golden Frills and Ruby Streaks in our hoophouse.
Photo Pam Dawling

Fighting Nematodes

When we learned our hoophouse soil had nematodes some years ago, we searched for resistant crops and were happy to learn that Brassica juncea greens were resistant. Although mizuna is not B. juncea, the more pungent frilly mustards are, so we focused on growing those, and ignored mizuna for several years.

Adding a Third Sowing

We were looking for a late winter nematode-resistant crop to follow our Koji, which I think bolts up to a month earlier than my long-time favorite Yukina Savoy. We tried the frilly mustards, sown February 1, and they were very successful. We got harvests from March 24 to April 23, a very worthwhile month of greens! I like greens that are harvestable in March and April, because this is really our Hungry Gap, the time when the stored crops are running out and the outdoor spring-planted ones haven’t really got producing much yet. I’m a bit suspicious of our record-keeping on the April 23 date – I suspect it was really over before that. It seems unlikely that this sowing lasts 30 days when the second one only lasts 26 days.

 

By trial and error, we found that our last worthwhile hoophouse sowing date for frilly mustards is February 12.

Bye bye mizuna! Bolting mizuna (our third planting) in our hoophouse in mid-April.
Photo Pam Dawling

Trying a Fourth Sowing

As part of a renewed effort to manage the nematodes, last year we added in a fourth sowing, on October 30. I haven’t got any records for that harvest to hand. I do remember though, that we had about as much “Frills” (as we now call them) as we could eat. We planted 30’ (9 m) in the first sowing, 50’ (15 m) in the new extra planting, 48” (14 m) in the November 9 sowing, and a whopping 120’ (36 m) in the February 1 sowing.