In the meanwhile, here's what Gordon had to say recently about the success of his tunnels in Silver Spring.
I am very excited to hear about the growing interest in - and success with - winter food gardening and low tunnels… we've definitely needed 'em this year! (Last winter I didn't close the low tunnel until, this year I was using it in November…)
Below are a few pictures of my own tunnel, before and after the December snowfall, and one of it after the most recent storm. I put down some shredded leaves for extra mulch, but other than that have just been depending on the tunnel and have been harvesting lettuce, arugula, turnips, mustard greens, broccoli (second shoots!), kale and chard right up to the present moment [January 5].
As for holding it down, anything heavy works but I use bricks - they are regular in shape and size, easy to move, and there is always something I can use them for in the garden in summer as well. (About one brick per 2 feet of tunnel seems to work fine.) You can also use the chenille method of securing the tunnel with clothesline (as described by Eliot Coleman in Four-Season Harvest), but if you have enough bricks it's not really necessary. (Although it does look sharp.)
I do hope more people get into winter gardening, and that we can give more classes on the subject. It really is a big step toward more sustainable self-sufficiency in food, it's fun, it's easy, and nothing puts a smile on my friends' faces like a garden fresh organic local salad in the middle of winter!
***So stay tuned for a report on Gordon's lettuces, and also whether the greens under plastic in the Derwood demo garden (and MG Robin Ritterhoff's back yard) survived temperatures in the low single digits. My guess is they're frozen beyond recovery, but you never know.
On January 21, Gordon will be giving a talk at Brookside Gardens on Food Gardening and Climate Change (sign up here) and keep an eye out at the MVG link above and the Montgomery County GIEI page for low tunnel classes coming in the summer.