I took apart a “9 Square” volleyball game I’d built to get 1-inch PVC pipe parts to build the greenhouse, which would be 5.5 feet cubed (see Figure 1). Door I wanted the door to be low-cost.

Greenhouses aren’t the only effective cover-ups for gardeners determined to extend the growing season. High tunnels, low tunnels and caterpillar tunnels work well, too. Also known as hoop houses ...