Many home gardeners long for their own greenhouses so they can grow plants for their own gardens. They want to grow their own plants to save money on expensive varieties, to grow varieties particularly suited for their own climates, and to have plants ready exactly when they want. Gardeners also enjoy the pleasure of extending the growing season beyond the summer months.
How much money can home growers actually save on plants grown in a home greenhouse? You can buy a packet of seeds for a couple of dollars, and one packet of seeds will produce between 25 and 100 plants, or even more, depending on the variety. Compare that cost to $5 to $15 for specialty plants, especially perennial plants and the increasingly popular xeriscape plants.
Most potential greenhouse owners want to know how much a greenhouse will cost. The easiest option is buying a prefabricated greenhouse, which will cost at least $1000 and often much more than that. Aside from the high expense, greenhouse kits and prefabricated greenhouses have the advantage of easy installation and good aesthetic value. Prefabricated greenhouses come in many shapes and sizes, and most retailers sell a multitude of accessories as well.
For those who cannot afford such an expensive greenhouse, there are several options for building one. The very cheapest greenhouse to build is the PVC greenhouse. One option is built by bending PVC pipe into arches, securing them at the top and on the ground, and covering with a flexible plastic covering. Free plans for such a greenhouse may be found online. These websites also gives free plans for a more conventional, house-like greenhouse made of PVC pipe. These PVC greenhouses might cost $250 and up, depending on the size. Advantages of PVC greenhouses would include easily obtained materials and moderately easy construction. Disadvantages include the relatively temporary nature of plastic construction and an unconventional appearance.
Among the most inexpensive greenhouse designs are dome greenhouses. There are several vendors of dome greenhouse kits on the Internet. These websites offers free instructions and also a multitude of kits to build your dome. Advantages are good customer support and good instructions, while the downside may be a slightly higher expense than the home gardener would prefer, as well as plastic components, which can be subject to breakdown over time.
Many gardeners have chosen an inexpensive alternative that is substantial and long-lasting, albeit unconventional in design. It is a simple dome built with Starplates. Starplates are specially designed steel plates engineered to receive predrilled lumber, either 2x2’s, 2x3’s, or 2x4’s. The completed structure is covered with a flexible plastic covering, woven poly being a durable, inexpensive favorite. Advantages are ease of construction and the low cost, about $300 from start to finish, as well as a more permanent installation than plastic. Disadvantages include an unconventional appearance, because the structure is a dome rather than a four-walled building. The size of the finished greenhouse depends on the length of the lumber chosen. This greenhouse, along with all others, requires good vents to be built into the design.
These types of inexpensive greenhouses work best for gardeners who wish to start seeds in the springtime or for those who want to extend the growing season. During very cold weather, a small electric heater designed for greenhouse use, or a mid-sized kerosene heater, would be appropriate for cold nights. During very hot weather, a small fan may be required. If gardeners want a year-round greenhouse, they may need to consider double-walled construction as well as a heating system.