Effect of Polyolefine Greenhouse Covering Film on Growth of Lettuce and Cucumber in Cool Season Cultivation

This study evaluated the effect of polyolefine greenhouse covering film on growth of lettuce and cucumber. The growth of lettuce and cucumber plants under conventional film (polyethylene plus ethylenevinyl acetate, PE + EVA) and polyolefine (PO) film were evaluated in a greenhouse. The physical qualities of PO film, such as tensile strength and tear strength, were stronger than conventional PE + EVA film. PO film showed 4% higher transmission performance in photosynthetic active radiation (PAR) than PE + EVA film. The average day and night temperature in greenhouse under PO film were 1.5oC and 0.8oC higher but there was no significant difference in relative humidity compared with conventional film. Chlorophyll content of lettuce and cucumber plants grown under PO film were higher than conventional film. Growth characteristics; plant height, leaf area, fresh weight and dry weight of cucumber was shown better for PO film. The yields of cucumber and lettuce was increased 14.0% and 13.6% respectively, when the crops were grown under PO covering film greenhouse.