Some lucky people who live in warm climates have hundreds of options when it comes time to choose the flowers, vegetables, and other plants they want to grow in their backyard gardens. Unless you live so far north that the snow never really disappears, there are always a few plants adapted to the climate that you can grow during the summer. However, if you want to grow more exotic plants that wouldn't normally thrive in your climate zone, you may need to build yourself a greenhouse.
Greenhouses are enclosed structures that trap sunlight using roof mounted windows in order to create a growing zone that is warmer than the surrounding outdoors. Depending on the quality of the construction and whether or not it has an interior automatic temperature calibration and moisture system, the greenhouse can be tailored to mirror almost any climate in the world regardless of what it's like outside. However, your basic home built greenhouse without fancy add-ons will just give you an area to grow in that's a few climate zones warmer.
Greenhouses can cost anywhere from a few hundred dollars to multiple thousands of dollars. No one wants to spend that money unnecessarily, so before you go rushing off to buy a greenhouse kit, you should first ask yourself if you really need one. Are the plants that are adapted to your growing zone inadequate in some way? Do you need more exotic plants for your business ventures? If so, investing in a greenhouse will be a good idea. For those who are only hobby gardeners, though, greenhouses are generally unnecessary, as the benefit of gardening comes from tending the plants, not from having specific plants grow.
If there are any plants you're not sure of, you can look online to see if they're appropriate to grow in your climate zone or ask at your local nursery. However, because soil and weather conditions can vary widely from backyard to backyard, the only real test of a plant's suitability is to buy one, plant it, and try to coax it to grow. If it won't it's more of a greenhouse plant than a garden plant.