Dear sir,
Environmental factors play main role in determining the quality of flower.
Temperature and light are
Plants need an optimum temperature for maximum yield and quality. The greenhouses in plain and coastal region of India needs cooling. The greenhouses in mild climates and coastal region can be naturally ventilated. The greenhouses for hot summer climates of northern plains have to evaporatively cooled or with fan and pad (FP). The greenhouses for northern plains may require both cooling and heating depending on the crop.
Natural ventilation
The greenhouse has to be thoroughly ventilated for control of temperature. It should be noticed that the temperature built up in the greenhouse is not exceeding 2°C throughout the year. Further during hot months the temperature in the greenhouse was same as the ambient temperature.
Unconventional method of heating and cooling
a) Hot and cold water can be sprinkled on the greenhouse covered externally with
the shadenet
b) Use of earth tunnel for cooling in summer and heating in winter
c) Construction of greenhouse in a trench for heating in winter cooling in summer
d) Circulating the borewell water in pipes laid on the floor of the greenhouse
Heating of greenhouse
The heating of greenhouses in cold climates like winter in North India or
Himalayan Region at high altitudes is advisable for getting better produce. Double
covering of glazing with an air cushion of 2 cm to 10 cm reduces the heating load
considerably.
Quality of light
Quality of light refers to its wave-length composition. Light in the orange-red portion of the visible spectrum from either sunlight or artificial illumination is most effective in causing the long-day response in plants. Far-red radiation appears to have the opposite effect. It is probable that the wave lengths activate some hormonal mechanism within the plant which brings about the specific effect of light on growth or flowering.
Fan and pad
Selection of fan
The fans should deliver the required air at 15mm static pressure. The maximum center to center spacing between the tow fans should be of 7.5m. The height of the fans is to be determined based on the plant height which is proposed to be grown in the greenhouse. The fan blades and frame are to be made of non-corrosive materials like aluminium/stainless steel.
Regards
Kirti s
