Yield response of a sweet pepper crop to different methods of greenhouse cooling

The influence of three methods cooling (white washing, fogging and forced ventilation) on the growth and yield of substrate grown sweet pepper crops grown in three similar greenhouses was evaluated. Cover whitening and fogging were the most efficient in controlling the maximum temperature and VPD, mainly during the vegetative development phase. The cooling methods adopted did not show any significantly different effects on total and marketable yield, despite the radiation reduction by the white wash. The crop subjected to the fog system showed the highest incidence of blossom end root (B.E.R.). The water use efficiency in relation to the marketable yield was higher with the whitening than with forced ventilation (16.2%) or with the fog system (29.2%). An economic evaluation showed that whitening was the most profitable cooling treatment.