0lpfan3217 11 years ago I've found one way to make a cheapy-but-a-goody greenhouse. It will take a pallet (4'x4'), velcro, staple gun, and some kind of heavy plastic that you can find at walmart or hobby lobby in the fabric section. You take four boards of equal length and make a square. Repeat and you have your two ends. Place two boards at the base and two at the top to join and you have a nice cube. Wrap the plastic over the three sides leaving an open bottom. Cut two more for the ends. Staple the plastic to the frame on all sides except the front. Staple the top of the plastic to the top of the frame. Then place your velcro along the sides of the plastic and frame so it will close securely. You really don't need a vent for this style, plus it's portable, so as the seasons change, you can move it for the best sunlight. To turn it into a coldframe, use clear bubble wrap on the inside. It works well for insulation and lets light in.