Study of inlet light spectrum’s effect on plants growth - the light transmittance decreased with increasing glass thicknesses

The aim of this study was to measure some effects of light spectrum on the growth of greenhouse plants to be able to reduce overheat in hot summer periods. To reduce the light’s impact two series of experiments were carried out. In the firs tests various double glass panels were involved. Light spectrometer was used to measure the transmitted light spectrum of the panels in empty and in different colour water-filled state. The red colour fluid was the one which transmitted the spectrum range appropriate for the photosynthesis of plants the best, it also filtered the IR range most. In the second test series three groups of strawberry seedlings were used to test the effect of filtered light transmittance. The plants below the red panel were taller, their leaf number was larger, and no sunburn was found compared to those under plain water and plain air.