A greenhouse is a controlled environment for growing tender plants when unfavorable environmental conditions exist. Greenhouses are ideal for small tropical plants like orchids, venus flytraps, and other carnivorous plants. Indoor growing allows pollen to become isolated and to readily multiply into more plants from cuttings.
In the 17th century, a greenhouse was only made up of ordinary brick or timber. Later, once glass became inexpensive and heat control technology advanced, they became walled structures with wood or metal skeletons. Today, these greenhouses serve as a place for horticulture and botanical science.
The plants grown in greenhouses are classified into several categories based on the type of greenhouse in which they should be grown. For example, sweet peas grow best in a cool greenhouse where the nighttime temperature is about 45°F. On the other hand, chrysanthemums and roses should be grown in a warmer greenhouse at a temperature of about 55°F.