Maximum Yield USA February 2019 | Page 52

Certain species of plants are subject to photoperiodism, in which the varying duration of light cycles between day and night cause plants to enter new phases of growth. To illustrate, uninterrupted 12-hour periods of darkness (nighttime) causes some plant species to start flowering. This process occurs when a hormone called photochrome reacts to sunlight intensity and durations, directing plants towards the different phases of growth. “It’s a good idea for cultivators to regularly check their growrooms to make sure they are 100 PER CENT DARK DURING THE NIGHTTIME PERIOD.” If a sealed growroom is not 100 per cent dark during the nighttime period, photoperiodism cycles can be interrupted, causing photochrome imbalances as related to specific plant processes. These hormonal imbalances can have negative and sometimes detrimental effects on an indoor harvest. For those looking to avoid issues with light leaks in their sealed growrooms, consider the following points: Inconsistencies and Stress Indoor gardeners should always strive for consistency in their growroom environments. Most crops perform best in stable environments, and bountiful harvests are the result of constant environmental balance — including stable lighting intervals — during both vegetative growth and flowering. A common misconception amongst indoor growers is that light leaks during the vegetative growth phase won’t disrupt crop growth. However, any irregularities in lighting patterns can stress plants out. Along this line of thought, all environmental stressors inhibit essential plant functions, such as nutrient uptake, and retard growth. Light leaks can also prove troublesome regarding photochrome levels in plants, as unexpected or irregular doses of light can alter stable hormonal conversion processes. During flowering phases, excess light during dark periods can push photochrome activity to the point of converting a plant back into vegetative growth. Hermaphrodites One of the most widely known negative side effects of growroom light seepage has to do with the transformation of female plants into hermaphrodites. For those looking to grow seed-free flowering plant varietals, hermaphrodites can prove devastating for a crop. This is because male flowers on a single plant can pollinate an entire growroom and greatly devalue a harvest. 52 Maximum Yield Expert horticulturists agree that certain plant species turn hermaphrodite as a result of environmental stressors, and light leaks are notorious for being associated with this phenomenon. However, it should be noted that the occasional beam of light on a garden from a headlamp won’t cause plants to “herm.” While indoor growers should strive to avoid any disruptions in regular light cycles, it takes rather consistent light exposure to force a plant into hermaphrodite growth. These sorts of leaks come from constant sources, such as under doorways and walls, that occur on a daily basis. Light Leaks Mean Other Leaks Indoor growers can be assured that if their sealed growroom is leaking light, it has issues with other leaks. Seasoned cultivators go to great lengths to ensure that their sealed gardens are functioning at their best when it comes to atmosphere, temperature, and sterility. All these contingencies are compromised with an improperly sealed growroom. If leakage issues arise, growers sacrifice the total environmental control that is so essential in sealed room growing. With this issue comes potential problems with maintaining ideal, static levels of temperature, humidity, and CO 2 . Moreover, as sealed rooms are wholly dependent upon CO 2 injection technology, the regular loss of CO 2 to leaks is financially burdensome and operationally threatening. If light leaks can penetrate the confines of a sealed garden, so can airborne pathogens. As such, it is virtually impossible to fully sterilize an indoor grow if bugs and spores (of powdery mildew and botrytis) can continuously access the grow space via leaks.