How to Build a Cold Frame

A cold frame is a tried-and-true historical gardening device which allows a gardener to extend the vegetable growing season by providing what is termed a "microclimate."  This microclimate is created by the cold frame's greenhouse effect; it captures the sun, heats the plants inside and insulates it from wind.  Here's how I built a cold frame:

First, I built the basic box frame.  The dimensions were dictated by the size of the glass window I had purchased, in this case an 18 1/16" x 32 3/16" basement storm window.  But, I had to take into account that the glass will be at angle, preferably in the 30-45 degree range.  Due to my window size, I had mine at about 23 degrees, because at 30 or 45 degrees, the frame would be prohibitively narrow.  The final dimensions were 16 9/16" x 32 3/16".  I used 1 1/4" wood screws at the corner joints, which made a much sturdier frame than the nails I used in my first attempt.

Second, I took a 16 9/16" piece (remember, this is the width of the box), and sliced it diagonally to fabricate two pieces that had the aforementioned 23 degree slant. 

I took these pieces and glued them to the box frame.  The glass will rest on these. 

Next, I cut some lengths of 2x2's to screw to the corners of the box in order to provide some extra strength and bracing.  Note that I also had to give the tops of the 2x2's the same slant to match the sides.

Now the back board I cut the same length as the foundation frame.  Then I put it on the table saw and ripped a 23 degree edge all the way down, as shown above.

After I screwed the back board on, the structure of the box was complete!

Now to the glass.  Since this was a basement storm window, I scored around the inside to rid it of the screen.  Then I set on the cold frame structure and attached two hinges and a handle.

Aaaand....we're done!

Now I can give it to the gardener in my family, so she can start with some early planting! :)

-Jonathan

Comments

[Dorothy]

That's such a great addition to your garden! It looks so nice! I'm sure your gardener sister will love it. :-)

[Tonya]

My gardener (14 yr old) will want one now. Can't wait to show this to him.