Evapotranspiration of horticultural crops in an unheated plastic greenhouse

Management and climatic conditions combined to define an unusual Kc curve for sweet pepper. The crop is transplanted in late summer and reaches the peak Kc in early winter. Because of the low temperatures, Kc decreased thereafter down to about 1.0, until climatic conditions inside the greenhouse improved. From late winter to the end of the season, Kc was either stable or increased steadily. A simple Kc model based on thermal time for greenhouse crops with and without pruning, was proposed and validated. The model gave accurate estimates of measured Kc values for melon and pepper.