Sunday, January 30, 2011

Cold Frame Update

I didn't use my cold frame as a cold frame in 2010 at all. N built it for me a couple years ago out of scraps from our kitchen remodel (that piece with the semicircles cut out used to hang over our sink and stove), and when I enclosed the bed with wood last year I accidentally made the bed larger than the frame that's supposed to fit around it. I hesitated to correct the problem because I wasn't entirely sure I wanted the wood frame anymore; for reasons that are entirely my fault, it was leaky and the old paint was chipping off and falling in the soil. Finally, during a warm spell a couple weeks ago, I went out and dismantled the cold frame and started installation of a low tunnel. (You may recall seeing low tunnels in the White House kitchen garden video I posted a long time ago.)

A low tunnel is basically a long piece of plastic draped over a series of half-hoops buried in the garden soil. The sides and ends are weighted/tied down so that the air inside the tunnel stays slightly warmer than the outside air. (Check out this pic.) So far I have cut 6, 9-12 inch pieces of 2-inch PVC pipe and buried them in the ground near the corners and center of the bed border. Next I need to buy some type of tubing to form the supports with. A lot of people recommend using more PVC because it's cheap and fairly flexible, but I don't think it's flexible enough to bend over a bed this narrow and be stable in strong wind gusts. You can also buy metal pipes and special pipe benders to bend them into just the shape you want, but I'm not sure I want to do that either. I may end up going to Community Forklift and looking for some appropriately malleable scrap metal. I have some plastic sheeting that I bought for the aforementioned remodel that I think I can use as a cover, although I'm not sure how good an insulator it is or how well it will hold up in sunlight. Commercially sold low tunnel kits usually come with plastic that's guaranteed for 5-6 years, but mine may only make it through one season.

I'll try to keep you posted on how this turns out and how well it works, assuming I get around to finishing it this year. I had a bad experience with slugs in my cold frame in 2009 and have been less enthusiastic about "season extension" since then. (FYI, Eliot Coleman, who has described many detailed plans for high and low tunnels, recommends raising ducks to take care of slug problems in your tunnels. If you think that's worth it. And hey, if I lived in Maine, I just might.)


  1. If you had ducks and let them wander through your garden, would they really just eat the slugs and not any of the plants?

  2. That part isn't really clear to me, probably because the premise "if I raised ducks" seemed so far-fetched that my brain quit paying attention. He may have intended that the ducks be allowed to wander the tunnels between plantings and clear out the slug population.