The main objective of the study was to compare the effects of two different heating regimes (13 degrees C and 5 degrees C minimum night temperatures) on plant growth, yield, fruit quality and fuel consumption in winter tomato cultivation. In spring tomato cultivation, yield and fuel consumption were also investigated. From winter cultivation (February 10-July 20) 24.04 and 19.05 kg/m(2) and from spring cultivation (April 5-June 11) 14.5 and 11.0 kg/m(2) total yields were obtained in 13 degrees C and 5 degrees C min. heated greenhouses, respectively. In winter crop, leaf number, main stem length, fruit weight and fruit diameter properties were significantly affected in the 13 degrees C heated greenhouse compared to the 5 degrees C heated one.