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Managing Humidity Made Easier with LED Lights

When working within an enclosed space, such as an indoor grow facility, cultivators must monitor and maintain healthy humidity levels. Installing LEDs can assist in stabilizing temperature and therefore humidity, creating an ideal environment for plant growth.

Humidity presents one variable that growers have consistently struggled with. Too little humidity and plants risk drying out. Too much, on the other hand, can also be problematic as a damp grow facility can lead to issues like mold and makes plants susceptible to rot. Most importantly, humidity plays an integral role in the plant’s ability to absorb the proper nutrients it needs to survive.

What you need to know about plant transpiration

The process of transpiration is essential to a plant’s growth. This process involves carrying moisture from the roots, to the leaves, where it is then released as vapor. Pores often found on the underside of plant leaves, called stomata, open and close to release the moisture and allow for the diffusion of carbon dioxide.

The process of transpiration is essential to a plant’s growth. This process involves carrying moisture from the roots, to the leaves, where it is then released as vapor. Pores often found on the underside of plant leaves, called stomata, open and close to release the moisture and allow for the diffusion of carbon dioxide.

Plants must transpire in order to successfully photosynthesize, regulate osmotic pressure of the plant cells and regulate temperature. Only a small percentage of water absorbed by the plants is actually used for metabolic functions; an estimated 97 percent is lost to transpiration. Some plants, such as varieties of cacti, have evolved receded stomata to conserve water.

Humidity affects how well a plant is able to transpire. Horticulturalists rely on a measurement called vapor-pressure deficit (VPD) to create a suitable environment for plant transpiration. VPD considers not only humidity, but also how leaf temperature interacts with moisture levels. VPD describes how much water the surrounding air can pull from the foliage, therefore, a VPD at zero means the air is at max humidity.

The highest level of humidity possible is termed dew point and describes the levels at which water begins to condensate on the plant leaves. As temperatures drop, water condensates. Condensation is not ideal — increasing the plant’s susceptibility to disease pathogens — but neither are overly dry conditions, which can result in too much evaporation thereby stunting plant size.

The right light helps create right conditions

Dramatic changes in temperature, which may be caused by hot HPS lights, can exacerbate issues associated with humidity. As the temperature swings from hot to cold, and cold to hot, VPD fluctuates and therefore inhibits a plant’s ability to photosynthesize.

LED lights run cooler than other lighting technologies, allowing the horticulturalist to better manage the temperature—and its effect on VPD—at an indoor facility. In addition, tunable and/or dimmable lights present even more advantages: the gradual increase or decrease in intensity prevents spikes in humidity, while also saving energy. This sunrise and sunset style to adjusting your lighting intensity can help in mitigating these fluctuations.

LEDs help horticulturalists discover that elusive humidity happy medium. By measuring VPD, growers can determine the best conditions to elicit the healthiest plants possible and an abundant harvest.