What in particular?
Anyway a greenhouse is a structure that modifies the climate making it possible for farmers to grow crops all year around.
It also helps to control pest and diseases since its enclosed controlling the movement of pests.
The greenhouse door should always be locked.
There ate quite a number of crops that can be planted in the GH. This includes strawberries, tomatoes, capsicum, kales, spinach etc.
In most cases drip irrigation system is used for irrigation or the over-head- use of sprinklers.