Greenhouses offer the advantage of starting your garden early or growing plants year-round. Since Missouri experiences freezing conditions during winter, starting new plants in a greenhouse, then transplanting them into the garden, means the plants enjoy a longer growing season with vegetables ripening a few weeks earlier. Plus, a greenhouse gives gardeners a chance to enjoy the thrill of gardening in winter, when the weather is too cold to do much outdoor gardening.
Choosing a Location
While greenhouses should be located where they get the most sun, a location that receives morning sunlight works best. The south or southeast side of a building works well. From November to February, greenhouses built on the east side get the most sunlight, making the location ideal if your greenhouse needs focus on growing plants to transplant into the garden in early spring.
Types of Greenhouses
Greenhouses come in all shapes and forms, with some attached to another building or built as freestanding structures. Lean-to greenhouses, one of the least expensive types, work well in limited space as long as you have an area measuring from 7 to 12 feet next to a building that the greenhouse can be attached to. Another type, even-span greenhouses, consists of full-size structures with one end attached to another building. Another option consists of passive solar greenhouses that rely on the sun to warm them rather than by artificial means.
For the budget-conscious gardener who needs a small space to grow a few plants for transplanting in the spring, greenhouses mounted to a window work well. The greenhouses stick out about a foot when attached to your window and feature two to three shelves on which your pots sit. Window greenhouses work best when attached to a south-facing window so your plants get all the light they need, especially in the winter.
Greenhouses can be framed with wood, steel or aluminum. Some plans call for wood or metal pipe frames. Even plastic pipe materials may work, although if Missouri experiences more wind or snow than usual, plastic pipe may be too weak for such a structure. Once the frames are built, you can cover them with glass, fiberglass, plastic film and double-wall plastics, depending on your budget and the structure you build.
Your greenhouse's heating system must maintain an adequate temperature both during the day and at night when temperatures fall. A home heating system usually proves inadequate to heat a greenhouse, but a 220-volt circuit heater may do the trick.
Watering plants in a greenhouse requires either a person or an automatic watering system. Even small greenhouses may contain a variety of plant materials, containers and soil mixes, each with different watering needs. Automatic watering systems rely on time clocks or sensors to know when to water the plants. Although Missouri gets plenty of humidity, you'll still need to use mist sprayers to create humidity in the greenhouse.