Cooler night temperatures combined with the warm sunny days often result in plant stretch. The greater the difference between day and night greenhouse temperatures, the more stretch you will see on your crops. Some growers may be only reducing the night temperatures, to save on energy costs, with the daytime temperatures increasing due to the bright sunny days.
Many growers successfully use an early morning temperature DIP to reduce plant stretch. They reduce the temperature 30 to 60 minutes before dawn and maintain this lower temperature for the first few hours of the day.