PLANT GROWTH BEHIND ENERGY ADVANTAGE™ LOW-E GLASS
The question is often asked if the growth of plants within a house will be adversely affected by glazing the window units with LOF Energy Advantage Low-E glass. A healthy plant that flourishes behind glass is the result of many variables, some of which include the type of plant, necessary wavelengths of light for plant growth, the percentage of light transmittance through the glazing unit at each specific wavelength and the internal room temperature where the plant is located.
Solar radiant energy in the form of visible light will act as a source of fuel for the internal food factory of a green plant. Through photosynthesis, plants use this visible light to change carbon dioxide and water into the simple sugars and starches they use for food, , .. giving off oxygen in the process. At night, when no light strikes the leaves, the photosynthesis stops and they start absorbing oxygen and releasing carbon dioxide.
A green plant does not use all the light that is available to it for growth, however. Although natural sunlight appears white, it is actually composed of separate wavelengths, each with its own color – red, orange, yellow, green, blue and violet. Plants will use some wavelengths more than they use others.
In most plants, green wavelengths are merely reflected, causing the plants to appear green to us. The influence. of the invisible infrared energy on plant growth is still unclear. Ultraviolet radiation is generally harmful to seedlings or younger indoor plants, although some data suggest that the longer ultraviolet wavelengths can slightly stimulate photosynthesis if visible light is also present in the correct proportions. Most of the important photochemical processes in a plant use the blue and red areas of the visible spectrum that best promote growth. Red light, for example, stimulates stem and leaf growth, while blue light regulates plant enzyme and respiratory processes and encourages low, stocky growth and dark green leaves. Providing your plants with the right balance of red and blue light is the key to successful indoor plant growth.
Insufficient window area or excessive shading can lead to inadequate light for healthy plant growth. The duration of light on a plant is just as important as the color and intensity of the light. Adequate light acting over a long duration will have the same effect as a very bright light over a short duration.
Therefore, plants will grow best behind a glazing having a high visible or daylight
transmittance. The visible light transmittance through a double glazed clear insulated glass unit will equal 90%. · A double glazed clear/LOF Energy Advantage Low-E insulated glass unit will transmit 82% of the visible light that is available from the sun. Therefore, there is less than a 10% reduction in visible light transmittance with the LOF Energy Advantage Low-E option.
Excessive ultraviolet radiation is generally harmful to plants, and therefore a glazing having low UV transmittance is desirable: A comparison between the two glazing options noted above result in values equal to 83% for the double glaze clear unit and 66% for the double glaze unit with LOF Energy Advantage Low-E or a 21% reduction in ultraviolet radiation.
Finally, plants grow ideally in indoor temperatures between 65 and 75 degrees F (18 and 24 degrees C). Window units glazed with Energy Advantage Low-E will certainly keep plants wanner in the winter with less reliance for heating energy supplied by the home furnace.
Research into plant growth behind low-e glazings conducted at the Massachusetts Institute of Technology (MIT) concluded that ” … neutral-colored low-e products do not seriously influence yields, plant health, or growth rates if the plants are kept near room temperature”.