A Green house is a building with different types of covering materials, such as a glass or plastic
roof and frequently glass or plastic walls; it heats up because
incoming visible solar radiation (for which the glass is transparent)
from the sun is absorbed by plants, soil,
and other things inside the building. Air warmed by the heat from hot
interior surfaces is retained in the building by the roof and wall. In
addition, the warmed structures and plants inside the greenhouse
re-radiate some of their thermal energy in the infrared spectrum, to
which glass is partly opaque, so some of this energy is also trapped
inside the glasshouse which plants are grown. Key factors which may be controlled include temperature, levels of light and shade, irrigation, fertilizer application, and atmospheric humidity.
TEMPERATURE
Ventilation
is one of the most important components in a successful greenhouse. If
there is no proper ventilation, greenhouses and their plants can become
prone to problems. The main purposes of ventilation are to regulate the
temperature to the optimal level, and to ensure movement of air and thus
prevent build-up of plant pathogens (such as Botrytis cinerea) that prefer still air conditions. Ventilation also ensures a supply of fresh air for photosynthesis and plant respiration, and may enable important pollinators to access the greenhouse crop.
IRRIGATION & FERTILIZER APPLICATION
Hydroponics is a subset of hydroculture and is a method of growing plants using mineral nutrient solutions, in water, without soil. Terrestrial plants may be grown with their roots in the mineral nutrient solution only or in an inert medium, such as perlite, gravel, mineral wool, expanded clay pebbles or coconut husk.
Researchers discovered in the 18th century that plants absorb essential mineral nutrients as inorganic ions
in water. In natural conditions, soil acts as a mineral nutrient
reservoir but the soil itself is not essential to plant growth. When the
mineral nutrients in the soil dissolve in water, plant roots are able
to absorb them. When the required mineral nutrients are introduced into a
plant's water supply artificially, soil is no longer required for the
plant to thrive. Almost any terrestrial plant will grow with
hydroponics. Hydroponics is also a standard technique in biology
research and teaching.
Aeroponics is the process of growing plants in an air or mist environment without the use of soil or an aggregate medium (known as geoponics). The word "aeroponic" is derived from the Greek meanings of aero- (air) and ponos (labour). Aeroponic culture differs from both conventional hydroponics and in-vitro (plant tissue culture)
growing. Unlike hydroponics, which uses water as a growing medium and
essential minerals to sustain plant growth, aeroponics is conducted
without a growing medium. Because water is used in aeroponics to transmit nutrients, it is sometimes considered a type of hydroponics.(Wikipedia)