Greenhouse growers wishing to maximize production and achieve plant uniformity should check out the benefits of diffuse light in a greenhouse. Diffuse light is a natural phenomenon whereby light is scattered as it passes through clouds, smog, and, yes, the appropriate greenhouse glazing materials. “By bathing plants in diffuse light, you can expect higher yields, higher leaf count, lower crop temperatures, and more uniform growth,” Michelle Moore with Adapt8 explains.
“A simple way to tell if the light entering your greenhouse is diffuse is to look for shadows. If the physical structures inside the greenhouse cast shadows, then light is not diffuse but rather direct sunlight. If, for instance, the sun is brightly shining and there are no shadows, then the light is diffuse and is helping to maximize growth in the greenhouse”, Michelle shares.
Direct light is just what it sounds like a light that falls directly on the surface of the plant. “This may be fine for the hobbyist, but not for the grower trying to maximize profits in the greenhouse. Direct sunlight not only casts shadows but results in hot spots and uneven growth.”
Also, direct light from the sun reaches mainly the tops or canopy of the plant. “This is a particular problem if you’re trying to grow in vertical racks. On the other hand, diffuse light can bend around corners, allowing it to penetrate the lower leaves and surfaces of the plant.”
Diffuse light reaching the lower leaves of a plant can increase photosynthesis and speed up plant growth by up to 25%. This will result in a quicker time to market–about three-quarters the time as plants grown in direct light. Diffuse light in a greenhouse can also increase flower production, reduce scorching, lower container temperature, reduce fungal spores, and decrease insect propagation (Bartok, 2017).
Working with existing greenhouses
Unfortunately, clear coverings, such as glass, acrylic, and single-wall polycarbonate, provide very virtually no light diffusion, Michelle explains. “Clear, twin-wall materials such as polycarbonate provide some diffusion as direct sunlight scatters in a narrow band running perpendicular to the flutes. On the other hand, materials with a milky-white appearance, such as polyethylene film, and our Solexx greenhouse coverings provide the best light diffusion in a greenhouse.”
If you don’t already have a greenhouse covering that diffuses light, you may be able to alter the covering on your existing greenhouse. For instance, you could mix latex paint and water and apply it to a glass covering. “However,” Michellle says, “this is not suggested for a polycarbonate covering because it could interfere with the UV coating of the covering. “
She explains how the industry standard 4 or 6 mil clear poly greenhouse coverings have limited light diffusion properties. To change this, an energy-saving infrared inhibitor can be applied on the inner layer of a double poly covering to enhance light diffusion, according to an article published in Greenhouse Management by John Bartok, professor emeritus at the University of Connecticut. It will provide about 50% diffusion while only reducing light transmission by a couple of percentage points.
Bartok says there are other ways to increase light diffusion on existing greenhouses. For instance, light exterior shade cloth can be utilized in late spring and summer to diffuse the light and lower the greenhouse temperature. A shade cloth will further cool the greenhouse but will also reduce light transmission to your plants.
In Search of the Ideal Covering
To realize the full advantage of light diffusion in a greenhouse, it is imperative–when you replace your existing covering or install a new greenhouse– that you purchase a light-diffusing greenhouse plastic that takes full advantage of the natural phenomenon of diffusion. “It’s important for the health of your plants and your bottom line. Greenhouses that utilize light diffusion simply grow healthier plants that finish quicker and are more uniform than those grown in direct sunlight. Solexx greenhouse coverings are recognized in the industry as not only maximizing light transmission that protects plants from intense heat but also providing a durable covering that can withstand the rigors of wind, rain, and whatever else Mother Nature sends our way.”
Solexx greenhouse coverings, manufactured and sold by Adapt8, is a long-lasting, durable greenhouse plastic covering with 100% light diffusion. According to their research, it also has the best r-value in the industry, saving growers money at a time when energy bills are soaring. “With a Solexx greenhouse cover, there will be less condensation and more even temperatures, providing for an overall better-growing environment and less stress on your plants. “
The Adapt8 offering includes a guaranteed 10-year limited UV warranty. The continuous roll eliminates seams, and since the products are fully recyclable, no plastic ends up in landfills. The products are inert and BPA-free, so they can be disinfected without off-gassing.
The Solexx greenhouse coverings retain heat 64% better than poly and has an r-value of 2.3R. “Even with heavy snows, they prove to be durable,” Michelle refers to several projects. “And without the need for seasonal whitewashing, the potential for injuries is reduced.”
However, the most important remains the consistent growth throughout the growing cycle, reducing labor costs associated with rotating plants. “Installation of Solexx greenhouse coverings is straightforward and is covered in several videos as well as an excellent tips sheet from Adapt8. In fact, if you can use a caulking gun and a drill to screw in the tap screws, you’re all set. In other words, there is no need to call a service technician and rack up additional labor costs”, Michelle concludes.
For more information: