A heat lamp keeps things hot. An ice box keeps things frozen. So, imagine my surprise when I found out that a cold frame keeps things warm.
For those of you who, like me until last week, have no idea what a cold frame is, let me fill you in. It’s a box with a glass top that you put in a sunny spot in your yard. You put your seedlings in the box, and it effectively extends your growing season because the sun sees to it that the box stays much warmer than ambient temperature.
Except when it doesn’t. If the sun refuses to shine, or the temperature becomes unseasonably cold, you either have to cover your box with a special insulating blanket or take your seedlings to bed with you.
This is an effort we’re willing to make in the service of earlier vegetables. Until we have produce, it’s all shellfish, all the time, so we’re very motivated.
Step one of building a cold frame is going to the dump. Don’t ever buy a frame with glass in it; windows and doors are the kind of thing people throw away all the time. We headed for the scrap heap and, In a matter of moments, found a perfect sliding glass door.
Step two is going to the lumber yard, a more expensive proposition. Our first choice of building material was cedar, since it is bug- and rot-resistant. It is also five dollars per board foot, which would have run our costs up to the $150. range.
Our second choice was treated lumber. Conventional wisdom has it that you’re not supposed to use treated lumber in gardens because one of the things it’s treated with is arsenic, which leaches into your soil and, from there, into your vegetables. I read up on this and discovered that A) there is plenty of arsenic-free treated lumber and B) although arsenic does leach out, it doesn’t travel well, and won’t affect plants that aren’t right next to it.
That research – which led to the decision to go with treated lumber – was the last contribution I made to our cold frame. Once we got everything home, I left Kevin in the garage with material and power tools. Three hours later, out came the cold frame.
If I leave him in there long enough, maybe that bigger boat will come out.