5 Questions with Rob Hanifin

Special Advertising Section - Special Advertising Section | Ask the Experts: Climate Screens

Greenhouses allow growers to cultivate cannabis under the sun while still controlling their environment—but sometimes all that natural light needs to be toned down. Ludvig Svensson Climate Consultant Rob Hanifin explains how growers can select and utilize climate screens to control day-length and regulate temperatures.

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July 9, 2020

1. What is the key to success when selecting and utilizing light-deprivation blackout screens?

You need a solution that’s designed to improve the growing climate by efficienttly managing light, temperature and moisture. You also want a screen that is designed and engineered to be both highly functional and that meets strict North American fire codes, adhering to the industry’s highest safety standards.

2. Can a true darkness be achieved with a light-deprivation blackout greenhouse climate screen?

Yes, however, that darkness for the plant differs from that of the human eye. It has been verified by research that the necessary darkness can be achieved. An ideal light deprivation screen should provide total blackout control for 99.9% darkness. A second, and equally important, consideration for reaching a true darkness is dependent on the installation of the screen. A proper install performed by a reputable company with proven climate screen-installation experience will prevent the risk of light leaks, which often are the result of a poor screen installation.

3. Can blackout light-dep screens have any negative effect on humidity in the greenhouse?

Humidity must be carefully managed under blackout screens. Selecting a “breathable screen,” which allows water vapor to pass through, is key for preventing moisture buildup and extreme spikes in humidity levels, and minimizing plant disease. A screen with a knitted structure has strong moisture-managing properties and prevents condensation on the screen.

As a cannabis crop matures, it can reach high levels of transpiration. During this period, “screen gapping” is often advised. A climate screen supplier with experience in various climates can provide advice for an effective and practical gapping regimen that’s designed to prevent excessively high Relative Humidity (RH) levels below the screen.

4. What other critical factors should growers keep in mind when selecting a blackout curtain?

An effective blackout screen is most often made up of double- and triple-layer options, providing complete versatility for specific climate needs. When selecting a blackout screen, consider an ideal layer configuration best suited for your growing goals. For example, an aluminum upper-layer option saves the most energy at night, while white reflective upper layers maximize cooling in hot, sunny weather. White is also useful as a bottom layer for intensifying supplemental light inside the greenhouse, whereas black is better for absorbing and restricting interior light.

5. What are the benefits of shade screens for cannabis crops?

Shading screens allow for more effortless control of your crop’s climate. Shading screens can help control light and temperature levels, providing an overall cooler environment for both the plants, as well as the greenhouse employees. Light-diffusive shade screens, which are designed to scatter sunlight to reach deeper and more evenly throughout the crop canopy, can be particularly beneficial for cannabis crops, leading to stronger, healthier plants and accelerated production. Thanks to its uniform light spread, a diffusive shade screen can contribute to more consistent bud sizes, as well.