The Best Humidity for Marijuana Plants
A common misconception when growing indoors is that humidity control is overly complicated and best left to mother nature, let’s understand why it is important to keep track of humidity when growing cannabis indoors.
Keyword: Relative Humidity - Or RH, is the measured amount of liquid vapor particles in the air compared to the amount of liquid vapor particles that the air can hold at its current temperature. So for example, a relative humidity of 50% means the air is holding 50% of its maximum liquid content, if the temperature were to decrease your RH would increase. Temperature and humidity control go hand in hand but their effects on growing are complicated, follow us here to read about temperature control and your indoor grow.
Your plant needs water to grow, the higher the humidity the less your plant will rely on it’s roots for water and the more it will absorb through its leaves. It’s important not to overwater a plant in a high humidity environment as it will drown, and die.
Why we like it - Maximum yield! Total control over the plant’s environment allows us as growers to produce more of the good stuff; resin and trichomes; which deliver high THC content and give your crop that extra punch. Keeping your plants in a humidity controlled environment can also help protect from mold or rot, a nightmare to discover after spending months tending to your plants.
What can go wrong? - Mold! Hah, yes while humidity can help prevent the growth of mold, too much humidity equals surplus surface moisture which will surely lead to rot. Any afflicted plants should be thrown out immediately - do not cook edibles with rotten cannabis!
White Powdery Mildew looks like it sounds - a light snow dusting a top your leaves. It is a fungal disease and should be avoided at all costs; you can prevent WPD by making sure your grow rooms have some form of airflow, like a fan.
Too much of a good thing, too little humidity and your plant will be forced to rely too much on it’s roots. This can go wrong if you’re using a high nutrient soil or fertilizer - your plant will become over-loaded by the nutrients and the tips of it’s leave will turn gold - orange.
Hygrometers -This is your tool, follow it as a priest would his bible. There are analog and digital varieties, the digital being more accurate at the cost of a higher price.
How to get it up: A humidifier may be expensive but it is an investment for your plants, other options are; hanging wet towels in the grow room, spraying the surface of the soil with a mister, misting the air around the plants. The latter methods are not consistent and offer a large margin for error; too much moisture for one night and your plant could mold!
Bringing it down: A dehumidifier works nicely, ensure your’s has a big enough drip tank as grow rooms are much more humid than the average living room the small ones are made for. Opening a window (depending on climate), a fan (or AC unit) or simply watering your plants right after the lights are turned on will lower the humidity in your grow room.
Seedling - Young: 60%-70% - Roots are young, the water will be absorbed through leaves.
Vegetative: 40%-60% - Roots are established and can drink for themselves.
Flowering: 40%-50% - The flowers are more delicate than leaves and stems.
Flowering Finish: <40% OR as little as possible (using a dehumidifier), this helps bring out the moisture already within the plant, hopefully that materializes in the form of tasty trichomes.
“If something’s worth doing, it’s worth doing right!” - This is a quote worth quoting when dealing with the intricacies of growing marijuana indoors, if you have not been enlightened by the effect temperature has on your crops, follow us here, as humidity and temperature are as closely related as can be. As always, stay botanical friends!