Saturday, March 14, 2009

Sprouting Spinach

Spinach kinda looks like grass, no? People may be wondering why I am so garden gung ho when my garden still looks like this.

I have constructed a secret weapon. Well, it's not really a secret to gardeners that routinely use season extenders. This week I put the finishing touches on my first cold frame.

The cold frame is a bit like a mini greenhouse. It takes in sun and warms the soil throughout the day, then at night the soil slowly releases the warmth back into the cold frame. It's a really simple means to extend the gardening season. The design of my cold frame is an amalgam of this design and the thoughts of Eliot Coleman in his book Four Season Harvest. By the by, I highly recommend anything written by Eliot Coleman. He's not only a master of his craft, but a very talented writer to boot.

I made my cold frame out of 2x12 and 2x8 stock. The back side is 12" tall and slopes to 8" in the front. The slope is meant to face south in order to maximize the amount of sunlight in the lower winter sun. The lids, or lights, are made out of a 2x2 frame with salvaged plexi-glass screwed to it. I put corner braces in each corner for support.

There are 2" hinges on the back side of the lids for opening and closing. Next time I'm going to use beefier hinges. The 2" ones are a tad flimsy.

The initial test of the cold frame was a success.

The power of the sun warmed the inside of the frame 34 degrees more than the ambient air temperature. I speculate that both temperatures were a little high since the test was done on the concrete right next to the garage. Nonetheless, the difference is what I was looking for. Now, I just need to dig a 4'x3'x3' hole in the glacier covering the garden.


  1. Now I understand the cold frame theory better. Good luck with it.

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