Abstract
The use of chemical growth retardants is a common practice in the greenhouse industry for controlling plant height for optimal shipping, handling, and establishment in the field. The mandated restricted use of some growth regulating chemicals in agriculture has led to recent developments in greenhouse film production. Photoselective greenhouse films offer a non-chemical alternative to regulate plant growth. Plant response to a photoselective plastic film with a far-red (FR) absorbing property was tested using the perennial Salvia x Indigo Spires'. Films were designated AFR (FR light-absorbing film) and control (clear plastic film). Light transmitted through the AFR film reduced plant height by 36%, leaf dry weight by 25%, and stem dry weight by 55% compared with the control film. This correlated with a reduction in specific leaf dry weight and specific stem dry weight. The AFR film did not significantly affect the number of leaves compared with the control film. These results indicate that compactness of Salvia x Indigo Spires' can be achieved by selective reduction of far-red wave lengths from sunlight.
