If you have decided to construct a free standing greenhouse, let’s look at the types of materials that you could consider for your framing. Depending upon your needs some are better than others.

Five basic types are galvanized steel, aluminum, pvc, wood, and fiberglass.

Galvanized steel’s best feature is that it is strong. I can, however, rust a bit even though it is rust “resistant.” Galvanized steel costs a bit to ship and may not be readily available for do it yourself construction but comes in some lower end greenhouse kits.

Unlike, galvanized steel, aluminum is also strong but will not rust and is lightweight. Aluminum is usually available in building supply stores. Aluminum can easily be drilled to provide holes to attach the greenhouse covering.

PVC is a material that is easy to work with, cheap, and available. It works well for Quonset type greenhouse frames as up to one inch can be bent to form hoops. Covering can be screwed to the hoops to cover the frame.

Wood can be used if it is treated to prevent deterioration. Any type of covering can be used over wood frames and it is even strong enough for a glass covering. It can be drilled and/or stapled to. Some higher end kits use pressure treated cedar or redwood as they are lightweight and strong. Redwood is one of the most attractive and lasts forever.

Fiberglass tubing can also be used in your framing. It won’t conduct heat or cold which helps to keep the heat in and the cold out of your greenhouse.