Chapter 10

Temperature Requirements for Greenhouse Crops

Average Daily Temperature for Greenhouse Crops

Average daily temperature (ADT) is an important concept in greenhouse temperature management. When we designate our air temperatures, we commonly set both DT and NT. As the name implies, DT is when light is present and the NT is during darkness. While both of temperatures influence growth and development, the primary factor controlling the speed or rate of growth is the average daily temperature. The ADT is the mathematical average of air temperatures over a 24-hour period. Plants integrate DT and NT over a 24-hour period and growth and development are strongly influenced by this integrated, average temperature. The ADT is important in that plant development generally responds to this value rather than the high and low daily temperatures of a greenhouse. Plants develop increasingly slower as the average daily temperature decreases, and increasingly faster as the average daily temperature increases. Therefore, if a crop is behind schedule, then the average temperature can be raised to speed development. If crops are ahead of schedule, the average temperature can be lowered to slow down plant development.

Click on the following topics for more information on temperature requirements for greenhouse crops.