What to Consider When Planning a Greenhouse

By Seth Mullins

A greenhouse is a nurturing environment for plants that is set apart from the rest of the world. It is a space wherein various conditions like heat, light and moisture can be controlled to a greater degree than is possible in any outdoor setting. Surely this degree of control has been a crucial factor in the increasing popularity of greenhouses. They can also be appealing structures in their own right, contributing to the beauty and harmony of our backyard environments.

Greenhouse Location:

When envisioning a greenhouse to be built from either our own plans or a manufacturer’s kit, first consider its placement. To support the growth of plants, the structure will need to be exposed to sunlight for at least 6 hours out of the day. Northern exposures, as a rule, will be too shady. Southern exposures are ideal; baring that, the order of preference will be southeastern, southwestern, eastern, and western. Also, a greenhouse with east-west orientation will enjoy more light than one oriented north-south, because more of its area will be facing the sun. Take into account other elements of the landscape, such as buildings, fences and trees, which will block sunlight for portions of each day. Finally, your greenhouse will be more conveniently located if it's close to sources of water and electricity.

Greenhouse Styles:

There are various styles of greenhouse design, each with their own advantages and disadvantages. Attached greenhouses are built as additions to the home. They are, therefore, conveniently located, and water and electricity is easily supplied. Additional work may be required, however, to make them directly accessible from inside the house. A-frames are simple in design and easy to build. Their pitched roofs are ideal for heavy snowfall, but they also limit the amount of headroom inside. Gambrel-roofs have higher ceilings and wider doorways, making them one of the most practical and popular designs.

Greenhouse Materials:

When choosing a greenhouse covering, your priority is to invite as much light inside as possible with the least possible loss of heat. Glass is the longest lasting material, provided that it doesn’t break. Glass coverings are available in double- and triple-strength ratings; and double-wall tempered glass reduces heat loss by a third. Film plastic is a much cheaper material than glass but typically lasts only 9 months to 5 years depending on the type. Film plastic can be double layered to reduce heat loss as well as tempered glass does. Rigid plastics, like fiberglass, acrylic and polycarbonate, are shatterproof and retain heat well. These materials need to be washed from time to time so that a soil film doesn’t accumulate and block light. Polycarbonate also tends to yellow in the sun, while acrylic will remain clear for longer.

When all the options of design and coverings have been weighed, you'll be in a better position to make informed decisions when purchasing greenhouse kits or separate materials to follow your own plans with. The dream of providing an enclosed world for your plants - one that you can control, for their benefit - will be that much closer to reality.