Controlling Relative Humidity in Indoor Grow Rooms

06 February 2020 /

No matter how good your mother plant is or your lighting system, if you can’t control the relative humidity of your indoor cannabis grow room, you’re putting the vitality of your crop at risk. In today’s post, we’re going to discuss the importance of controlling relative humidity in your indoor cannabis grow room with a right-sized HVAC system.

What is Relative Humidity?

If you’ve ever felt 85 degree weather in Florida and 85 degree weather in Arizona, you understand the importance of humidity on your comfort level. Sticky, humid Florida weather feels a lot more oppressive than the dry air of the desert. 

When weathermen talk about humidity, usually what they mean is relative humidity, or the ratio of current absolute humidity (how much water is in the air) to the highest possible absolute humidity. Because hot air holds more water than cold air, we have to talk about relative humidity and not absolute humidity to understand the environment. When relative humidity is high— say 90%—  that means the air is close to completely saturated. And because humans cool off in hot weather by sweating (aka releasing water into the air via perspiration and evaporation), if the air is already full of water, there’s nowhere for that sweat water to go.

Why Indoor Growers Struggle with Relative Humidity

Similar to humans, plants “sweat” in their own unique way. They release water into the air via transpiration, keeping themselves and the environment around them feeling cooler. But, when you trap thousands of plants into a room, all of which are transpiring water vapor into the air, and combine that with hot grow lights and poor temperature control and air circulation, you’ve set yourself up for troubling microclimates and moisture problems. 

Growers like indoor facilities because, unlike the outdoors, it gives them a chance at year round productivity and consistency. But not controlling the relative humidity for each unique stage of the plant life cycle can doom the quality of your cannabinoid expression and your plant’s vitality. 

That means you need an indoor grow room HVAC system that can address the challenges of adjusting the relative humidity in your facility. You can’t just toss in a dehumidifier and call it a day: you need to address variables like the temperature, the stage of your plants, and the day/night fluctuations. 

Indoor grow rooms are more likely to suffer from high relative humidity. What happens when humidity is too high? 

Like people, when relative humidity is high it slows down the ability to transpire or sweat. Unable to regulate itself properly, Because they can’t release water, the roots slow down their intake of water and nutrients, which has many compounding negative effects on the quality of your plant.

When the humidity is too low, though, too much water could transpire from the leaves, so it responds by slowing down the photosynthesis process. This leads to stress, slowed growth, and potentially plant loss.

Tips for Controlling Relative Humidity through the Plant Life Cycle

Different stages of the cannabis plant’s life cycle and cannabis manufacturing process require precise set points for temperature and relative humidity. 

To manage the relative humidity in your commercial grow room, you’ll need to be able to confidently: 

  • lower humidity,
  • raise humidity,
  • lower temperature,
  • raise temperature.

With a cannabis grow room HVAC system from InSpire, you’ll be able to control all of that from anywhere in the world thanks to an integrated HVAC system that unifies your temperature, humidity, and airflow into one unit.

Let the trusted experts at InSpire help you develop a right-size HVAC system for your grow room. Contact us today!