This time of year my greenhouse begins to run over with the perennials I've overplanted. So lately I have built a couple of cold frames to take the overflow. They are cheap and easy to build, so I thought I would post some pictures and instructions in case anyone else would like to build one.

Here's what you'll need:

3- 2x4x8'

2- 1/2"x20' pvc

1- 8'x15' piece of poly film

8- 3" deck screws

1/4" staples

Cut one of the 2x4's in half and cut a 20 degree angle on each end. Drill six 7/8" diameter holes, about 2" deep, in one edge of each of the two remaining 2x4's with one centered 3/4" from each end and four more in each one spaced evenly. Screw the frame together with one screw low in each corner. Cut the pvc into six pieces about 6' long. Install the pipe arches and then drill pilot holes and install the other four screws in the corners. These screws will go through the end pipes and lock the whole frame together.

Spread the plastic out on a flat surface. Turn the frame upside down on the poly. Pull the poly tight and staple it to the bottom of the wood frame. Trim off the excess. Cut holes for ventilation, if desired.

For the shorter cold frame, which is great for sheltering seed flats for winter sowing, buy your pvc in 10' lengths and cut them in half. The angle on the ends of the short 2x4's will have to be increased to about 30 degrees. On the short cold frame I put chicken wire on the ends by screwing a piece of old water hose to the undersides of the two end pipes and stapling the wire and the plastic to these.

For watering, etc., just raise one edge of the cold frame and prop up with a stick.

I plan to take mine apart for off-season storage, but if you want more permanent structures, use pressure treated lumber and uv-resistant poly. Have fun.

Fred

Here is a link that might be useful: Cold frames