Dampness, especially of the air. Relative humidity; Humidity is a measure of the amount of water vapour contained within the air which is usually expressed as percentage humidity.
Humidity is a very important environmental element that must be controlled for healthy plants, and connoisseur grade meds. Humidity controls the rate of transpiration and how the nutrients are received by the plant. Just as with humans, if the humidity gets too low, our skin can become dry and flaky. We transpire by sweating more fluids out in lower humidity levels. The humidity level is like a pressure cap on the plant, keeping the moisture in the plant, allowing it to have proper transpiration rates of the fluids. Ideal humidity levels in a grow room range between 50% to 70% in vegetative growth, and 50% to 60% for flowering plants.
When humidity levels drop too low, the plants transpire at a rate much quicker than that of nutrient uptake. The nutrients or minerals do not transpire thru the plant, only the water does. So this leaves behind a concentrated level of nutrients in the plant that will actually cause a nutrient burn. Most people don’t realize in situations like these that the humidity could be responsible; usually thinking that it is too many nutrients in the reservoir. Just as a lack of CO2 can cause a plant to go dormant, low humidity can cause a plant to have nutrient problems, resulting from the transpiration rate being much too high in low humidity level environments.
Conversely, when humidity levels get too high, moisture is building up on the plants and walls, forming whole colonies of molds, fungi, and mildews. Even if you had none of these developing before the high levels, the moisture would create the perfect environment for all of these to start developing, in a very short amount of time. These pathogens will destroy your garden if not taken care of immediately. This is one more reason why a controlled, closed loop, sealed room is the best way to build and run a grow room, as you can control every element of the environment with the right equipment.
This is the reason that it is paramount to control the levels in your room! This is where the HR15 & HR50 Humidifiers come into their own.