Journal of Applied Horticulture. 2001: 3(1): 28-31

Environmental conditions and gerbera production under different types of greenhouses

Mandhar, S C; Singh, K P; Kumari, C R

Indian Institute of Horticultural Research, Hessaraghatta Lake, Karnataka, Bangalore - 560 089, India.

The naturally ventilated greenhouse (NVGH) and fan- and pad-cooled greenhouse (FPGH) were designed and constructed for conditions in Bangalore, Karnataka, India. Gerbera crop was cultivated in both greenhouses and temperature and relative humidity (RH) were recorded at 10.00, 13.00 and 16.00 h. The temperature in NVGH could be brought down very near to ambient temperature during hot and dry months by proper irrigation. The maximum temperature during the year in NVGH was 36.6 degrees C when the ambient temperature was 35.4 degrees C and RH 28.4% at 13.00 h in April. The maximum build up of temperature of 2.5 degrees C was recorded during rainy and cloudy days when the ambient temperature was low and RH was high. The average build up of humidity on a yearly basis in NVGH was 1.5% above the ambient RH. The drop in temperature up to 8.2 degrees C was observed in FPGH in April when the ambient temperature was very high (35.4 degrees C) and ambient RH was very low (28.4%). The maximum temperature of 30.1 degrees C at 13.00 h was observed in FPGH in September when the weather was cloudy and ambient RH was very high at 62.1%. The build up of 0.1 to 1.6 degrees C of temperature was recorded in FPGH when the months were rainy or cloudy. The FPGH did not produce any cooling effect when ambient RH was >56%. The NVGH performed better by yielding more and better quality flowers per plant. The NVGH can be used under Bangalore conditions for raising better yield and quality gerbera flowers.