Last night I made our first salad of the winter with some beautiful red leaf lettuce from our low tunnel. We thought the low tunnel would provide spinach throughout the winter and expected the lettuce to bite the dust during the single digit temps in early December.
As it turns out, the spinach harvest has been pretty minimal (Matthew transplanted the spinach to the tunnel from its previous location in the garden, which may explain its lack of enthusiasm), and the lettuce, which is much less cold-tolerant than spinach, somehow survived. While the low tunnel keeps things warm enough to prevent freezing, it’s still pretty chilly in there, which means that spinach, lettuce, or anything else, will grow veerrrryyy sllloooowwwlllyy.
Matthew harvested just enough lettuce leaves for a nice salad for two. I dressed it up with some chopped cauliflower, red onion, toasted sunflower seeds, and this homemade dressing, which features nutritional yeast, and savored every bite of homegrown lettuce in the middle of January.
Her Green Life 
Wow! That’s a pretty fancy schmancy tunnel! I’ve done winter spinach for the past 3 years or so, and my system is not nearly as fancy… the first few years I just covered it with plastic… last year I graduated to frost cloth, but I’ve never done hoops or anything. I do give it an extra blanket when it gets down into the single digits, but it’s survived nineteen below zero with only the plastic. (Important safety tip: if you’re gonna add a blanket on top of the frost cloth during a storm, put a layer of plastic between, otherwise the snow will seep through the blanket and it will freeze to the frost cloth… at which point it’s really hard to get them separated without destroying the frost cloth!)
My best results were achieved by planting in a plot that’s up against a south facing wall because it gets extra heat, but given my plant rotation system, this plot is not always available come fall planting time. So for the past few years I’ve tried putting plastic bottles filled with water between the rows to absorb the sunlight during the day and keep it a bit warmer at night. Not sure how much it helps, but the leaves right next to the bottles do seem to grow a bit faster. Mine are just clear plastic bottles salvaged from other people’s trash, but I’d bet that if you used something darker in color it might absorb more heat and do a better job. I’ve also seen people cover the dirt with black plastic with holes where the plants are. I think the idea is that the dark plastic absorbs the heat from the sun and keeps the dirt warmer. Next year I may try building an actual cold frame with some glass I salvaged from an old sliding glass door, but I’m sort of afraid it will get too hot if I’m not vigilant about propping it open on warm days…
Have you ever done a cold frame?
We haven’t done a cold frame, though I do have a nice pane of glass that I found beside the dumpster and rescued with a cold frame in mind. The low tunnel theoretically has the same issue as the cold frame as far as needing to be vented on warm days, though we haven’t run into a problem with this yet. Maybe we should try the bottles of water to make it warmer and promote growth. Some people paint empty milk jugs black, but I’m nervous about having the paint in my garden.
Hi Melissa. I actually found your blog via a comment you left on the Tiny Choices blog. I was excited to see someone else from St. Louis doing similar things! When I saw the picture of your lettuce in your low tunnel, I was amazed. I tried the same thing, but my hoops and plastic blew over during the first snow and my arugula, spinach and other lettuce froze, so I took it all down (last year was my first year vegetable gardening). I still have my carrots under a small hoop house an hope that I’ll get some good ones in the Spring. Anyway, I’ll be checking in on your blog and I’m looking forward to reading about all the green things you do in the area!
Hi Stacey, glad you found my site. Thanks for reading! We rather expected our tunnel to blow over or collapse under the weight of snow, but so far it is holding strong.