Humidity Control

The wrong humidity in your grow room or tent can be an ideal way for fungal infestations to get to your plants, slowing down growth and making it easier for certain insects to reproduce. Keeping an eye on humidity is necessary in indoor grows. Let’s have a look at the best ways to adjust humidity during each stage.

The Importance of Humidity in Indoor Grows

When it comes to growing cannabis indoors, humidity is a key aspect. Cannabis plants absorb water through their roots, and they transpire via their leaves. Low humidity levels can delay plant growth and directly affect yield. Plus, certain infestations reproduce quickly in dry environments. Excess humidity is also a great way for fungal infestations to occur, especially during the advanced flowering period when plants need to transpire more and buds are thicker.

Humidity Levels for Indoor Cannabis Plants

Recommended humidity and moisture levels for cannabis plants can vary depending on the stage they’re in.

• For the first few days, we recommend keeping humidity high, as your plants’ roots haven’t properly grown yet and they use the small leaves they sprout after germination in order to feed. During this stage, humidity should be at about 65 – 75%. If you plan on growing using clones rather than seeds, increase humidity to 75 – 85% during the first week, then lower it to 65 – 75%. In order to achieve such high humidity levels we recommend using a propagator.
• During the growth period, plants have enough to successfully grow with about 50 – 60% humidity. This allows for the plant to grow strong and sturdy, producing plenty of plant mass.
• At the start of the flowering period, your plants don’t need quite as much humidity as the growth stage. During this stage you’ll need to make sure humidity is at around 40 – 50%. We recommend reducing the temperature and humidity progressively during this stage in order to achieve the best results.
• During the more advanced stages of flowering, your flowers will have grown and should be fattening up; humidity should be at 30 – 40% during this stage, because dense buds are incredibly susceptible to fungal infections such as botrytis.

How to Measure Humidity in Indoor Grows

In order to measure humidity in your grow tent or grow room, you can use a thermo-hygrometer, designed to measure both temperature and humidity with max and min values. Thermo-hygrometers are ideal for figuring out the exact parameters of your grow room, allowing you to take action and adjust them if required.

How to Control Humidity in Indoor Grows

The first step to keep humidity under control is to set up a ventilation system and extraction fan. By renewing the air and removing any pockets of hot air in your grow tent using fans and extractor fans, you can easily reduce humidity. One of the best options for humid grow rooms or warm grow rooms is to use an AC system or various AC systems, used to lower temperature and dry out the environment.

However, if the temperature in your grow room is right and you only have issues with humidity, we recommend using humidifiers or dehumidifiers, which are much more precise.

The Best Humidifiers for Cannabis

Humidifiers generate cold vapor or mist via the vibration of a ceramic membrane. They’re ideal for increasing humidity without also affecting the temperature. Check out our catalogue for models such as Pure Factory’s 8L Humidifier, which allows you to adjust the vapor quantity and direction; this device also has an indicator that shows when the tank is empty. Another great option is the Mist Maker, ideal for increasing humidity in each phase. This model is available in one or five membranes, ideal for all types of grows.

The Best Dehumidifiers for Cannabis

Sometimes the issue can be the exact opposite, and you may end up with a growing area that has high humidity; this is quite common during the flowering period. If this is your case, it’s important to reduce humidity as soon as possible, and to do this you can check out the following products in our catalogue:

• Mini Cornwall Dehumidifier: this device has Peltier technology (no compressor) meaning that it’s quite light and silent, ideal for small spaces.
• Cornwall dehumidifier: this device comes in two formats, depending on the needs of your grow; one that can absorb up to 10L a day, and another that can hold 12L a day. This device has a rubber tube on the back to set up a drain.
• With twice the power, the Industrial DH-202B Dehumidifier by Pure Factory can absorb up to 20L of water a day in grow rooms. This device is designed for areas up to 25 – 35 square meters, with a height of 2.6 to 3 meters.
• For large rooms you can try out the DH 504-B Industrial Dehumidifier by Pure Factory, capable of absorbing up to 50 litres a day, designed for 50 – 70 meters of grow room and a height of around 2.6 – 3 meters.
• In order to control the humidity and temperature in your grow room you can also use the Fan Controller, an extraction fan adjuster that allows you to control timing depending on the humidity and temperature inside your grow room.

If you have any questions regarding how to control humidity and temperature in your cannabis grow room, get in touch with our team of experts at La Huerta Grow Shop.