Time to plant our hoophouse for winter

Many of you may already know about hoophouses. They are unheated greenhouses that allow growers to harness the sun’s power during the winter to grow veggies. I live not far from Michigan State University’s Student Organic Farm, which uses hoophouses for research and to extend the growing season for their farm market and CSA sales. (CSA stands for Community-Supported Agriculture where members buy shares of whatever the farmer produces.)

My husband and I were so impressed with what this new technology can do that we put up our own 26 by 36 hoophouse, completed this spring. We enjoyed a bountiful (and early) harvest of warm-weather crops, but now that it is time for our fall planting, I am realizing how complicated this new way of gardening can be.

The first decision is what to plant. Then when to plant. And whether to plant seeds directly or start seedlings indoors for transplanting.

And what do you do with the summer plantings that are still producing? That patty pan squash plant is still reliably giving me a new squash or two every week, so do I rip it out? And what plants can follow other plants without increasing the risk of disease and insect problems?

When in doubt, I rely on two trustworthy sources. First is Eliot Coleman, whose book “The Winter Harvest” is my bible. The second is Michigan State University hoophouse specialist Adam Montri. Click here for his free handout on fall plantings for hoophouses in Michigan, adaptable to other cold Midwest states.

Unheated winter greenhouses can produce abundant harvests of root crops, various greens and onions. The trick is mastering the timing. Growth in winter slows dramatically, so Coleman says that you need to have most of your crops close to harvest stage by the time that the daytime sunlight drops to 10 hours a day. Wunderground tells me that we are down to 11 hours and 49 minutes of daytime today, and the day will be 2 minutes and 51 seconds shorter tomorrow. By my calculation, I have roughly one month more before the big slowdown.

I began starting seeds indoors in August, even though it seemed counter-intuitive to use electricity to start plants indoors when the sunshine outside is free. But the problem is that many of these cool- and cold-weather plants find August temperatures too hot for good germination and early growth.

The other problem, of course, is space. My hoophouse in August was filled to the bring with summer plants that were booming.

The picture above (taken yesterday) shows that the romaine, mache, various lettuces, spinach, chard, kale and beet seedlings started indoors and planted two or three weeks ago are doing great. (Mache, also known as corn salad, is a type of lettuce that Coleman recommends, along with minatura, for winter production. I rely on Johnny’s Seeds for these varieties.)

I also direct-seeded turnips, beets, carrots and lettuce at various times during the last six weeks, but I am worried that many were planted too late to grow big enough to fare well during the winter.

We have not yet had a frost this fall. Those milk jugs painted black are ready to be filled with water, so that they can absorb solar energy during the day and radiate it back at night as an additional temperature boost at night.

My hoophouse does not enjoy a frost-free water hydrant, so it will tricky deciding when to roll up the hoses before they freeze solid. I visited Adam’s hoophouse last January, and he said that he never had to water during the winter. Let’s hope I don’t have to yoke up the dogs like oxen to carry pails of water in January and February.

Once I begin to understand hoophouse dynamics better, I want to explore other possibilities for small-scale, home winter food production. Simple cold frames or “low tunnel” hoophouses two or three feet high offer tremendous promise as a much-lower price.

Coleman writes that the French placed glass cloches over fall plantings in their fields outdoors a century ago, as many as 3,000 on one farm. Like the hoophouse, the glass would allow the sun to come through and heat the plants during the day. Farmers would also cover them with a blanket of ryegrass to insulate them further. But imagine the hard work it took to prop up each of those cloches on days when the sun got so intense they needed to be vented - and then put them back down at night.

Our production dramatically reduced our summer grocery bills. Meijer for me is now the place to buy toilet paper and root beer (and I have a kit to start making my own root beer as well). Let’s hope my winter production feeds us well this winter.