When deciding whether to purchase a greenhouse or a hoop house two factors need to be considered, budget and the size of the structure you want to build. The biggest difference is cost. If space is limited and only a small structure is possible, than a green house is the better choice. They are more pleasing to look at and require less maintenance, and give the best light transmission. With larger structures over 200 sqft. (20 sq meters) a hoop house is the best choice for cost-effective food production.
Glass is transparent and admits more light than plastic, warms the house more quickly and retains heat longer. Plants, particularly those with high light requirements such as tomatoes, grow better under glass than plastic. Glass lasts indefinitely, while plastic becomes brittle and breaks down with age.
What Size Greenhouse – A popular size is 6ft. (1.8 meter) wide by 8ft(2.4 meter) long. A path 2 ft (60cm) wide down the middle allows 2 ft. (60cm) on each side for plants.. A better size is 8ft(2.4meter) wide by 6ft(1.8 meter) long. This arrangement allows for 3 ft(90 cm) on either side of a shorter path, giving additional plant space.
Where space is limited, a lean-to greenhouse maybe an option. The problem of lack of light on one side can be generally alleviated by painting the wall of the inside of the greenhouse white. A sunny wall is best for a general purpose greenhouse. A lean-to greenhouse on a wall that does not get direct sunlight is good for cuttings, ferns or plants whose natural habitat is the forest floor.
Materials for Greenhouse Frames – The most commonly used materials are wood and aluminum. Aluminum is light and strong and is low maintenance. Aluminum greenhouses vary considerably in quality. In poorer quality greenhouses the glazing bars consist of T-sections. The better quality aluminum greenhouses consist of H-sections.
If you are considering a wooden greenhouse the best choice is cedar. Cedar is very durable and does not require toxic wood preservatives. It is a good choice if you can be sure it comes from sustainable, managed source. Wood is a better insulator than aluminum, but the thicker glazing bars required block more light.
Greenhouse Glazing- Glass is the most common glazing material, tempered for safety, if necessary. An alternative is polycarbonate plastic- a twin walled, lightweight, tough material that provides good insulation. The biggest negative of this material is it is not see-through, and only allows 85% light transmission as opposed to 97% for glass.
Adequate vents– for good air circulation and temperature control are vital. An automatic vent opening system is a worth while investment. Unexpected sun, even in spring can cause a rapid temperature rise if vents are closed, and plants can suffer. With the spiraling costs of produce a greenhouse is a great way to grow produce or fruit year around.