Back-up plans for winter hoophouse crops

Lettuce “filler” transplants to fill gaps.
Photo Pam Dawling

Because crops grow slowly in cold weather, if something goes wrong at the beginning of the winter, or in the fall, the consequences can cast a long shadow. It is not easy to make up for lost time. In spring, the weather is getting warmer, the daylight is lengthening, and you may have noticed that later sowings can catch up with ones a week or two earlier, allowing for a second chance. In the fall, the rate of growth is moving in the opposite direction, and later sowings will stand no chance of catching up. Even worse, they may get “trapped” like Persephone in the Underworld during the dark Persephone Days. But don’t despair – there are things you can do ahead of time to be prepared for plans going awry, and there are even a few things you can do instead of your original plan, to ensure you get some crops to harvest.

Transplant seedlings under insect netting outdoors.
Photo Pam Dawling

Starting outdoors in September

We sow a lot of our winter crops outdoors in September, and transplant them into the hoophouse in October. This gives us an extra few weeks to prepare the hoophouse beds, and gives the seeds the cooler outdoor conditions to germinate in. We have three sowing dates.

On September 15, we sow 10 varieties of hardy leaf lettuce and romaines; pak choy, Chinese cabbage, Yukina Savoy, Tokyo Bekana, Maruba Santoh and chard

On September 24, we sow another 10 varieties of lettuce; Red and White Russian kales, Senposai, more Yukina Savoy, mizuna and arugula, and we resow anything that didn’t do well in the 9/15 sowing

On September 30, we resow anything that didn’t do well in the 9/24 sowing, or substitutes.

Emergency back-up seedlings for the hoophouse.
Photo Pam Dawling

This year, we had poor germination of a lot of the 9/15 sowings and too many of the 9/24 sowings. As a back-up for the back-up plans we sowed some crops in Winstrip trays, and spotted lettuce in open flats, which we kept inside the hoophouse. By that point, conditions in the hoophouse were more crop-friendly than outdoors. We did need some of these, and the rest we harvested for salad mixes right out of the flats! We were short of salad items because of the late establishment of the plants, so every plant was a help!

A flat of lettuce transplants in the path in the hoophouse.
Photo Pam Dawling

Our goal is to keep the space filled with useful crops.

Success with this goal relies on a cluster of strategies

  1. The fall transplant program I describe above.
  2. Follow-on crops: A sequence of different crops occupying the same space over time. It’s important to know when crops will bolt, and how to plant sensible quantities
  3. Filler crops: As well as scheduled plantings, in October we sow a few short rows of spinach, lettuce, Senposai, Yukina Savoy, Maruba Santoh, Tokyo Bekana to transplant into gaps as soon as they occur. We simply dig them up, replant where needed and water well. Bare-root transplants are much easier than many fear. They save time and money, compared to growing starts in flats, and save on greenhouse space. They are very sturdy plants, as they have the full depth of soil to develop big roots. Little extra care is needed, as they are less prone to drying out than seedlings in flats. Alternatively you could keep some plug flats of these plants handy. We fill gaps with Asian greens, spinach or lettuces as appropriate, until Jan 25. From Jan 25 to Feb 20 we fill all gaps everywhere with spinach From Feb 20, we only fill gaps on the outer thirds of the beds, leaving centers free for tomatoes, etc.

    Filler brassica transplants in our hoophouse in November.
    Photo Pam Dawling

  4. Interplanting: After 2/20, we harvest the winter crops from the center rows first, plant the new early summer crops down the center, then harvest the outer rows bit by bit as the new crop needs the space or the light. This overlap allows the new crops to take over gradually. Our winter and spring crops end in April
  5. Fast Catch Crops. Some cool-weather crops mature in 60 days or less. Mostly these are greens and fast-growing root crops. Useful if a crop fails, or you have a small empty space. Details on some of these follow the list.
  • Ready in 30–35 days in fall, longer in winter: arugula, many Asian greens (Chinese Napa cabbage, Komatsuna, Maruba Santoh, mizuna, pak choy,.Senposai, tatsoi, Tokyo Bekana and Yukina Savoy), brassica salad mixes, chard, kale, radishes, salad greens (lettuce, endives, chicories) spinach and winter purslane. Peashoots in late winter or spring.
  • Ready in 35–45 days in fall: chervil, corn salad, land cress, parsley and sorrel.
  • Ready in 60 days in fall: beets, small fast cabbage, collards, kohlrabi and turnips.

 Asian Greens

Asian greens are better able to germinate in hot weather than lettuce, and are faster growing than lettuce. Transplant 2-3 weeks after fall sowing, or direct sow.

Asian greens are nutritious as well as tasty – flavors vary from mild to peppery – read the catalog descriptions before growing lots. Colors cover the spectrum: chartreuse, bright green, dark green and purple. A diversity of crops without a diversity of growing methods!

Brassica (Mustard) Salad Mixes

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 10/2 and 11/14 for winter harvest and from 12/4 to 2/12 for March and early April harvests. We’re zone 7, central Virginia.

Chard and Beet Greens

Green chard is hardier than the multi-colored Bright Lights. Days to maturity: 61 – 103 days, a big difference, depending when you sow. Sow 9/15, harvest 11/15 – 5/10; Sow 10/26, harvest 2/6 – 5/10.

Radishes in our hoophouse in February.
Photo Pam Dawling

Radishes

Varieties we like: Easter Egg, White Icicle, and Cherry Belle.  Sparkler got too fibrous for us, as did Cherry Belle after mid Oct. We make 6 sowings 9/6 – 1/26. Small radishes take 27–52 days to maturity, not counting days too cold to grow.

Scallions in our hoophouse in late November.
Photo Pam Dawling

Scallions

We sow 9/6 for harvest 12/1 – 3/1; 11/18 (following radishes) for harvest in early spring. This winter we are trying a sowing 10/20 also (we happened to have a space at that time, in a spot where it fitted our rotation). Evergreen Hardy White and White Lisbon scallions are hardy down to 0°F (-18°C)

Spinach

We loved Tyee and now grow Escalade, Reflect, Acadia and smooth leaf Renegade. Renegade makes good Nov/Dec growth; Acadia, Escalade yield well Jan – April; January sown Reflect does well.

  1. Succession Planting for Winter Hoophouse Crops

We do 2 sowings of chard, scallions, tatsoi and yukina savoy; 3 sowings of  mizuna, turnips and bulb onions; 4 sowings of baby lettuce mix and brassica salad mix; 5 sowings of spinach and radish. Our goal is to provide a continuous supply.

As temperatures and day-length decrease in the fall, the time to maturity lengthens – a day late in sowing can lead to a week’s delay in harvesting. As temperatures and day-length increase after the Winter Solstice, the time to maturity shortens – later sowings can almost catch up with earlier ones. To get harvests starting an equal number of days apart, vary the interval between one sowing date and the next accordingly. Here’s the most dependable method:

Making a Close-Fit Plan Using Graphs

  1. Gather sowing and harvest start and finish dates for each planting of each crop you are growing as successions.
  2. Make a graph for each crop: sowing date along the horizontal (x) axis; harvest start date along the vertical (y) axis. Mark in all your data. Join with a line. Smooth the line.
  3. From your first possible sowing date find the first harvest start date.
  4. Decide the last worthwhile harvest start date, mark that.
  5. Divide the harvest period into a whole number of equal segments, according to how often you want a new patch.
  6. Mark in the harvest start dates and see the sowing dates that match those harvest dates

Overgrown hoophouse filler greens in our hoophouse in December.
Photo Wren Vile

Working around the Persephone Days

In Indiana (in Zone 5b) Ben Hartman (The Lean Farm) sows salad greens & spinach for winter harvests every week Sept 15–Oct 15. Baby lettuce sown before Oct 22 takes 5–6 weeks until harvest. If sown Oct 24–Nov 16, it takes 8–17 weeks to harvest. In Zone 5b, if you want baby lettuce mix before December, sow before Oct 22.

Spinach sown before Oct 11 takes 4–6 weeks to harvest. If sown from Oct 20–Nov 1, it takes 12–15 weeks. To harvest spinach before December, he sows before the middle of October.

For new year harvests he sows every week Oct 15–Nov 1. He then takes a two month break from planting (Nov-Dec). Jan 1–Jan 15 he sows both salad greens and spinach for late winter.

In Zone 7 we can harvest outdoor lettuce and spinach in December, and we have less urgency about early hoophouse sowings (and we get no winter break!).

 

 

 

 

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