The cheapest and possibly most effective way to humidify a small growroom consists of a bowl, a towel and maybe a clothes hanger. If you experience dryness in the growroom and don’t want to invest in a humidifier, check out this simple method.
Large-scale growrooms need to look into reliable and tunable methods of humidification, but there’s no reason a small grower, with even up to 20 plants, should go for a DIY method like this. Furthermore, ultrasonic, impeller and sprayer humidifiers that put water droplets directly into the air can cause problems. They can spread bacteria and mold and require constant cleaning. Even if kept clean and smoothly running, whatever minerals and chlorine in the water will directly into the air and get deposited on the leaves and buds of your plants. Evaporative and steam humidifiers avoid this problem, but why stack them onto your electric bill and overhead when you know there’s a better way?
So-called natural humidifiers work by simple evaporation off a wicking material. A lot of fancy jargon, but a natural humidifier consists of a bowel and towel, and maybe a clothes hanger. Take a small hand towel, fold it once or twice and place it in the bowl so it lines the inner surface and sticks up the sides, then fill the bowl with an inch or two of water. That’s it. The towel will absorb the water, become completely wet. This creates a very large inner surface area where water will constantly evaporate off of giving the room a gentle and safe level of humidity. You’ll be surprised how fast the water disappears right into the air.
Monitor the humidity level with a hygrometer and figure out how many bowls and of what size you need to keep the humidity level at 50 -60% saturation. You will want to change the towel every few days and wash the bowl to prevent build-up of mold and bacteria.
Check out this video that shows how to make one of these simple humidifiers, except this one uses a clothes hanger to hang the towel over the bowl of water, which generates significantly more surface area than just leaving the towel sitting in the bowl.