Homes with "Low-E" glass windows have a special glazing added to the glass that enhances the insulation effects of the glass by blocking some ultraviolet and infrared light from penetrating through the glass. Because Low-E windows modify the sunlight filtering through the glass, some indoor gardeners wonder whether they can grow plants near Low-E windows. Once you understand how Low-E windows work, you can determine which plants will grow best near these windows.
Compare the amount of sunlight that transmits through a standard double-paned clear window and a Low-E double-paned window. According to Pilkington North America, a standard window transmits 81 percent of the available sunlight. One Low-E window transmits 75 percent of the sunlight and a different Low-E window designed to block more sunlight transmits 59 percent of the sunlight. The difference between the first two windows is 6 percent and the difference between the second two windows is 22 percent.
Note the amount of ultraviolet light that filters through windows. Comparing the same three windows, Pilkington states that the first window transmits 57 percent UV rays, the second window transmits 45 percent and the third window transmits 38 percent. According to a NASA website, excessive ultraviolet radiation can harm some plants, contributing to decreased growth. Low-E windows may provide a beneficial growing environment because they block some UV radiation.
Select plants that require medium direct sunlight for best results. Place the plants about 12 inches away from the windows for ideal light exposure. Provide water and fertilizer according to the specific plants' needs and monitor the health of the houseplants. If you notice the plants declining with yellowed foliage, decreased growth or failure to bloom, the plants may need more light.