Greenhouse Microclimate as Influenced by Poly Film Covers and Its Effect on Growth of Rose Cut Flower (Rosa hybrida spp.) Cultivars

Greenhouse covering diffuses light that reaches the plant canopy. The diffused light has been found to be advantageous since it prevents shadow formation and enhances light penetration. A myriad of greenhouse covering material have been developed for this purpose. However, spectrum properties and their effect on plant growth are continuously being discovered under different conditions. A field study was conducted in 2012/2013 in a growth tunnel to investigate the effect of UV-A 205/N, UV-A milky white and IR-504 poly films on growth of two rose cultivars under natural conditions. The research was carried out under a split plot experiment laid down in a completely randomized block design. The covers exhibited differences in microclimate (greenhouse air temperature, relative humidity and photo synthetically active radiation). The amount of PAR recorded was high under UV-A milky white poly film compared to the coloured IR-504 and UV-A 205/N. Long grades of rose cut flower were obtained under UV-A 205/N cover which received low PAR compared to those grown under UV-A milky white and IR-504. UV-A 205/N had high dry matter accumulation for both stem and flower heads. Dry matter accumulations of plants grown under UV-A clear and IR-504 were not significantly different. Temperature and relative humidity varied significantly (P<0.05) under different poly films, these differences had implication on the stem length of rose cut flower. It is evident from the study that UV-A 205/N and IR-504 poly film enhanced production of longer rose cut flower stems compared to UV-A milky white.