In this research, the effects of a double plastic cover and of thermal screens on greenhouse temperature and tomato plant development have been investigated.
During the nights when the screens were covered, the lowest minimum temperatures relative to the unscreened single plastichouse, were 2.5°C, 3.4°C and 3.4°C higher in the double covered roof plastichouse, the LS-17 screened double covered roof plastichouse and the PE screened single plastichouse, respectively. On the other hand, double covering of the roof and thermal screens did not affect early yield in spring, although it increased total yield in comparison with other plastic houses having no screens. The highest yield, 10.33 kg/m2 was obtained in the PE screened single plastic house. This value was 1.67 kg/m2 higher than that the single plastic house. In the autumn growth period, double covering of the roof and the screens did not completely protect the plants from frost. But frost damage was slightly reduced and delayed.