Greenhouses can be used to effectively farm various plants such as flowers, fruits and even vegetables within its controlled environment wherein humidity, condensation and light are the key factors that contribute to its effectiveness. These structures are generally freestanding however other designs may also be joined to the house or built in a lean-to manner.
The size of greenhouses also varies depending on the purpose of the structure. Miniature greenhouses may simply be a window extension that can be used for growing herbs while massive greenhouses can be as wide as block and usually for business purposes.