This study was carried out in three greenhouses covered with a different color (blue-red-transparent) at the experimental area of Isparta University of Applied Sciences. Data on temperature, humidity, solar energy and development parameters of the lettuce plant were acquired from research greenhouses. Solar energy values vary between 202-890,8 Wm(-2) in COG (control greenhouse), 179-606,7 Wm(-2) in BG (blue greenhouse) and 212,6-770,1 Wm(-2) in RG (red greenhouse). It was determined that all values such as fresh weight, body diameter, number of leaves, plant height, stem length, bitterness and bolting ratio were high in the COG. When the values of BG and RG were examined, it was determined that the plant height and bitterness were higher in the RG, fresh weight, body diameter, number of leaves, stem length and bolting ratio were higher in the BG in comparison with RG. It is a desirable quality feature that the rate of bitterness and bolting ratio in lettuce is low. BG has the lowest rate of bitterness, while the lowest rate of bolting is determined in the RG. It is concluded that the rate of bitterness and bolting in the region will be obtained by using colored covering material for the lettuce plant.
