THE EFFECTS OF ROOT ZONE WARMING AND LOW NIGHT TEMPERATURE ON THE GROWTH AND QUALITY OF SPRAY CHRYSANTHEMUMS IN NUTRIENT SOLUTION CULTURE

Spray chrysanthemums were grown in nutrient solution culture at higher than normal densities.
The effects of root zone warming and low night air temperature during the short-day phase on the quality of the spray were studied.
Night temperatures of 7°, 9°, 11° and 15°C were combined with ambient, 21°, 24° and 27°C solution temperatures.

The quality of flowers produced at the normal air temperature was very satisfactory.
At the lower temperature regimes, quality traits such as stem length, stem strength, flower diameter and pedicel length were increased with a consequent improvement in spray quality.
Flower numbers per stem, however, were reduced and flower head (spray) diameter was unchanged with most cultivars.

Root zone warming had little effect on spray quality.
It did, however, reduce the pedicel length at low night temperatures and increased the flower number per stem at all air temperature regimes.

The use of a 9°C night air temperature regime during the short-day phase of these experiments had an energy saving potential of 60%.

Symposium on Chrysanthemum

A.T. Moustafa, J.V. Morgan

https://doi.org/10.17660/ActaHortic.1982.125.16