SHADING ORNAMENTALS WITH PHOTOSELECTIVE NETS: AN ENVIRONMENTALLY FRIENDLY METHOD FOR INCREASING THE YIELD AND IMPROVING THE ROOTING OF CUTTINGS FROM MOTHER PLANTS

The sensitivity of plants to light properties can be exploited to improve the quality of ornamental products such as cut flowers and pot plants. By filtering sunlight through photoselective screens, the characteristics and direction of light reaching ornamentals can be controlled. We have introduced the use of photoselective plastic shade nets, affecting both the light spectrum and the ratio between direct and scattered light in the net house, as a method for improving ornamental growth. Here we present an experiment carried out in a commercial pelargonium nursery producing pelargonium cuttings. The effect of shading pelargonium mother plants with five different photoseletive nets was tested on the two cultivars, ‘Samantha’ and ‘Fernando’. The results vary between the cultivars: the highest yield for ‘Samanatha’ plants was under the Yellow net, with a 16% increase in yield in comparison to the Black neutral net. The highest yield for ‘Fernando’ plants was under the Red net, showing a 14% increase in the number of cuttings per plant. The Yellow, Blue and Pearl nets increased the rate of rooting of ‘Samantha’ cuttings, but had not significant effect on the rooting rate of ‘Fernando’ cuttings.