Winter hoophouse growing

 

Hoophouse Yukina savoy at the end of November.
Photo Ethan Hirsh

Last week I wrote about Winter Preparations for Vegetable Gardens. For those with a hoophouse, here are some notes on all the work we can do to grow winter crops there! For those without a hoophouse as yet, scroll to the end for Twenty Benefits of Having a Hoophouse

First, a roundup of previous blogposts on winter hoophouse topics.

Planning winter hoophouse crops includes a description of how we do our hoophouse crop planning so we can maintain a crop rotation and still pack the beds fully with hardy crops.

Fall hoophouse bed prep and shadecloth removal includes spreading compost, broadforking, and a step-by-step guide to hoophouse fall bed prep.

Hoophouse fall bed prep Plans A-D and spider-webs includes some lovely spider photos and a short video of ballooning, as well as info about our first-planted winter crops.

Hoophouse bed broadforked to loosen up slumped soil. I’m happy to say our soil structure has improved in the 18 years since this photo was taken!
Photo Pam Dawling

Young greens in the hoophouse

After the set-backs with our winter hoophouse greens transplants that I wrote about in Hoophouse fall bed prep Plans A-D and spider-webs, we worked really hard and got the whole house planted up. Most of the transplants have recovered from their transplant shock (wilting each day), during the cloudy weather we had.

The new seedlings are coming up fast and calling on us to thin them. We ended up not needing so many of the Plan D plug flat plants, but we’ve kept them for now “in case” .

Plan D: Winstrip seed flats in our hoophouse on Oct 16, a late attempt to catch up!
Photo Pam Dawling

Ultimately if we don’t need them, they’ll go in a salad mix. I wrote about Making baby salad mix last year. The past two days I have been able to harvest a mix in the hoophouse. The ingredient we are shortest of is lettuce. My first mix was spinach, Bulls Blood beet leaves, a few leaves of Tokyo Bekana, Bright Lights chard, Scarlet Frills, Ruby Streaks and Golden Frills, and a handful of lettuce leaves Red Tinged Winter is growing fastest, of all the varieties we planted this year.

Sowing hoophouse winter crops includes some discussion of the tools we like; pre-sprouting spinach seed and growing multi-leaf lettuce.

What’s growing in the hoophouse; reading; planning for winter is an October view of crops.

Frilly Mustards in our Winter Hoophouse is exactly what it sounds like. Four sowings, six varieties. All delicious.

Making baby salad mix includes a discussion of ingredients and methods, balancing nutrition, color, shape and loft.

Young green Panisse and red Revolution lettuce in our hoophouse in November.
Photo Pam Dawling

Cold-tolerant lettuce and the rest, our January 2018 assessment of the varieties we grew that winter and which survived the unusually cold spell we had. Includes sad photos of the casualties!

Also see my Mother Earth News blogpost from August 2018 Grow Great Lettuce in Winter

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Hoophouse seedlings growing outdoors under insect netting. Starting transplants outdoors helps the rotation by reducing the time the crop is growing in the hoophouse
Photo Pam Dawling

Do you value crop rotation in your hoophouse?

In the winter 2019-2020, 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.”


Doing a spot of research today, I find that Heterorhabditis bacteriaphora, (Hb nematodes) a beneficial nematode fromArbico Organics will attack flea beetles. also known as NemaSeek, and sold separately. This is the wrong time of year for introducing nematodes in most of the US. They need warm weather to thrive.

Another suggestion from Arbico is BotaniGard Maxx & other B. bassiana sprays, which infect and kill adult flea beetles. Repeat applications as needed throughout the growing season.

Kaolin clay (Surround) is another possibility.

Also see Harvest to Table on the topic of dealing with flea beetles

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View through the hoophouse doors in December.
Photo Kathleen Slattery

Add a hoophouse to your food production

For those of you wistfully thinking about a hoophouse, let me help you a step closer to having one next year! Sales of my Year-Round Hoophouse book are doing well, which suggests to me that quite a few gardeners and growers are thinking in this direction.

Twenty Benefits of Having a Hoophouse

  1. An extended growing season because plants are protected from cold weather.
  2. Faster growth and higher total yields.
  3. Beautiful unblemished crops not battered by the elements.
  4. Fewer foliar diseases because the leaves can stay dry.
  5. Crop survival at lower temperatures in the hoophouse than is possible outdoors.
  6. Better crop recovery in winter due to warm sunny days following the cold nights.
  7. Some protection from deer and other pests large and small.
  8. Soil temperature stays above 50F (10C) in zone 6b. Warm soil = faster cold weather growth.
  9. Higher proportion of usable crops – more food, higher sales dollars.
  10. Diverse crop portfolio – grow crops that wouldn’t succeed outdoors in your climate.
  11. Harvest whenever you need the crops, even during pouring rain!
  12. Wonderful working conditions – no need for gloves and hats; take off your coat.
  13. A food garden on a manageable scale.
  14. A place to enjoy practicing intensive food production.
  15. The chance to have an area completely free of weeds – new weed seed doesn’t blow in.
  16. No need to work with heavy machinery.
  17. Much better value for producing crops (per dollar invested) than a heated greenhouse.
  18. Can be constructed by generally-handy people. Specialists are not needed.
  19. NRCS grants are available for some hoophouses. Natural Resources Conservation Service, Environmental Quality Incentives Program, High Tunnel System Initiative.
  20. Ecological energy use. The embodied energy of the plastic is less than the energy that would be used to ship similar produce from somewhere warmer (Eliot Coleman, Four Season Harvest). Another study found this was not true for smaller (9 x 12 m) hoophouses – although the economic incentive for growers is still true, there is no energy efficiency advantage to the planet. Smaller carbon footprint: shipping 1 kg lettuce has 4.3 times the CO2 footprint of locally grown hoophouse lettuce. Plawecki, R., Pirog, R., Montri, A., & Hamm, M. (2014). Comparative carbon footprint assessment of winter lettuce production in two climatic zones for Midwestern market. Renewable Agriculture and Food Systems, 29(4), 310-318. doi:10.1017/S1742170513000161.
September sown White Russian kale (transplanted in October).
Photo Wren Vile

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Know your climate

WeatherSpark climate summary for Louisa, Virginia. Go to the website to click for more information

The WeatherSpark website provides “The Typical Weather Anywhere on Earth”. Enter your nearest town or airport and you get clearly explained info with fascinating graphics of how the weather goes over the year in your locality. Note this is not a forecast site, it’s about average weather for each place. Useful to people who’ve recently moved and want to know what to expect this winter, or to new gardeners who haven’t paid so much attention previously. Or to those who want to check their assumptions (I really thought the wind was out of the west more of the time than records say). There are charts of high and low temperature, temperature by the hour each month, cloud cover, daily chance of precipitation (both rainfall and snowfall), hours of daylight, humidity, wind speed and direction and solar energy. A big help in making wise decisions. I know that climate change is going to cause havoc with averages, and we’ll need to learn to become better weather forecasters individually, and to use soil temperature and other metrics to decide when to plant. This website explains things well.

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Winter gives a time for most of us to ponder success, failure, and possibilities for doing things differently.

 

Cold weather, snow, thinking about nematodes

We won't starve or get scurvy! Plenty of food in the hoophouse!  Credit Twin Oaks Community
We won’t starve or get scurvy! Plenty of food in the hoophouse!
Credit Twin Oaks Community

This morning we have about 6 inches of snow. Knowing it was coming, we stocked the kitchen with extra potatoes from the root cellar (for those who don’t know, it’s next to impossible to pull a loaded garden cart through loose snow). We also braved the begiinning of the snow yesterday afternoon to harvest some spinach outdoors. We did try digging leeks, but the ground was frozen too deep. If the weather forecast holds true, we won’t see the soil for a week, as not much thawing is predicted. But the hoophouse will feed us. One winter the outdoor crops were inaccessible due to snow, ice or freezing weather, for a whole month, and we were able to feed 100 people in salads and cooking greens from the hoophouse. That wasn’t typical central Virginia weather. But typical isn’t typical any more.

Young blueberry bush in the snow. Credit Bridget Aleshire
Young blueberry bush in the snow.
Credit Bridget Aleshire

Our hoop house is a 30 x 96 ft Clearspan Gothic Cold Frame type from Farmtek. We made ours with bows four feet apart for better strength against ice and snow build up, and the gothic arch shape helps shed snow, as does the rigidity provided by having two layers of plastic and an air bubble. A couple of years ago when we were changing the plastic we added some reinforcement props to the west wall, which was leaning in from the force of winds. On Sunday night I was very glad of that, because we had very high gusty winds, and I lay in bed trying to ignore the sound of the wind, imaging we would lose our hoophouse. Imagine my relief to wake up to see it still in place!

We did have a big pine tree come down near our dining hall, but it missed the big propane tanks and didn’t even block the road by the Tofu Factory. We didn’t lose electric power either, so we have been lucky in several ways. Now I am watching the forecast for Thursday night. At one point the forecast was for a low of -9F, which is unthinkably low! Even the Vates kale won’t survive that – unless we have snow covering, which we still might! Currently the forecast has “warmed” to -2F. We always subtract 5F from the Louisa forecast, because it is often that much colder here.


Meanwhile, here are some warming photos from Hawai’i. Following my article in Growing for Market about dealing with nematodes in the hoophouse, I heard from Gerry Ross at Kupa’a Farms on Maui, at  2000 feet above sea level. (Take a look at their beautiful website, and feel the sunshine!) Root Knot Nematodes are a warm weather problem – they are inactive if the soil is colder than 50F. We had never seen their damage until a few years ago. In warmer climates they may have to deal with them constantly. On Maui the soil temperatures never go below 59F! Their high tunnel is for insect exclusion, not warmer temperatures, so it is covered with insect mesh, not polyethylene.

Nematode-susceptible food crops. Credit Gerry Ross, Kupa'a farms
Nematode-susceptible food crops.
Credit Gerry Ross, Kupa’a farms

Gerry wrote that he is trying a hoophouse crop rotation: “We started with cukes, tomatoes, zukes, and peppers for the hotter summer weather. We then moved to sunn hemp-Piper sudan cover crop for about 45 days, and then to a winter rotation of brassicas with peas and cukes. We will mow and disc the brassicas down in about a month when it starts to get on the warm side and harvest is over and plant directly into the debris with peppers, tomatoes and cukes/zukes. So far we are really pleased with the results…..the brassicas are really clean with no cabbage moth damage. This is just one way to manage the RKN I suspect but so far so good.”

Nematode -fighting cover crops. Credit Gerry Ross, Kupa'a Farms
Nematode -fighting cover crops.
Credit Gerry Ross, Kupa’a Farms

Outdoors, for field crops, Gerry said:

” we usually do 2-4 month cover crop like sunn hemp and Piper sudan grass and then follow that with our most susceptible crops (potatoes, carrots, beans, beets). When those come out we follow with brassicas, lettuce, onions. We usually grow row crops for 8 months in a field and then do a cover crop. The sunn hemp we use is called “Tropic Sunn” and the USDA on Molokai has developed it and bred the alkaloids out of it. Not sure it is widely available but try http://oahurcd.org/ and see if they will mail it to you. We also use vetch as a cover but it can get whacked with RKN so we co-plant with a scaffolding nonhost like the Piper sudan or oats.”

Brassicas in nematode-fighting hoophouse crop rotation. Credit Gerry Ross, Kupa'a Farms
Brassicas in nematode-fighting hoophouse crop rotation.
Credit Gerry Ross, Kupa’a Farms

“Buried in some of the research by the sugar cane companies was a comment that molasses seems to drive down populations of RKN in the soil. We found application of local molasses to be difficult because it is so thick and viscous and hard to make spreadable BUT a local farming store did get us some dried molasses which is used as a horse supplement in the Mainland and applying that to the soil seemed to really help. That might be something you could try.

We have tried lots of compost (food-waste based as manure is not easily available here) and have created beds with loads of earthworms but the RKN persists.
We have found that some lima beans perform well even with heavy RKN infestation esp the Florida speckled butterbeans (huge purple speckled beans on wild vines that live for three years here!) and Fordhook that seem to just carry on regardless of RKN infestation. Fava beans on the other hand suffer mightily and do not produce at all. 
Thank you for the list of remedies and resistant cultivars. We have used the NemaQ and it seems to work if we run through our drip lines or water it in in diluted form in our raised beds. We might try grafted tomatoes too because one of the available rootstocks is RKN resistant. “

So, here I sit with “good garden planning weather” and fight my desire to just hibernate till it warms up!
Field manual Vabf unnamed