Use of Colored Shade Netting in Horticulture

Higher plants respond to light quantity, quality, direction, and periodicity. There are numerous photoreceptors in plants, including chlorophylls, phtyochromes, cryptochromes, phototropins, and ones that react to green light (Batschauer, 1999; Folta and Maruhnich, 2007). Light, along with other environmental cues, enables plants to adapt to environmental conditions. Efforts to manipulate plant morphology and physiology using photoselective filters have been ongoing for decades, especially in greenhouse environments (Cemy et al., 2003; Ilias and Rajapakse, 2005; Kambalapally and Rajapakse, 1998; Li et al., 2000; Mortensen and Stromme, 1987; Rajapakse and Kelly, 1991, 1992, 1995; Rajapakse et al., 1999; Wilson and Rajapakse, 2001a, 2001b). More recently, colored shade netting (shadecloth) designed specifically for manipulating plant development and growth has become available. These nets can be used outdoors as well as in greenhouses. They can provide physical protection (birds, hail, insects, excessive radiation), affect environmental modification (humidity, shade, temperature) (Perez et al., 2006), and increase the relative proportion of diffuse (scattered) light as well as absorb various spectral bands, thereby affecting light quality. These effects can influence crops as well as the organisms associated with them.