Grow Room Humidity Guide

Humidity is a significant concern for cannabis cultivators. So, why is humidity important for the marijuana plant, and what is the proper control of a specific grow room humidity needed to maintain in your growing area?

When you buy marijuana seeds to create sticky, high-potential buds, your marijuana will need to put effort into several of its needs. Remember that humidity is essential for developing a cannabis plant, sometimes overlooked.

Although you like it or not, humidity is essential for your cannabis. Humidity can let you understand your plant’s resistance to mildews and common mold, as well as how much water it needs to absorb. Getting the appropriate mix can help them thrive and grow and provide you with abundant yields.

Having the option to grow room humidity is a fun and easy learning experience. With a bit of effort and care for your crops, you can perfect them. This post will teach you about humidity and how to enhance your cannabis plants’ productivity.

Understanding why humidity in a growing environment is essential.

Throughout the cannabis cultivation process, your crops will require regular water consumption, with the amount varying according to the level of humidity in your growing region. When the humidity is high, your marijuana plants will use their leaves to absorb moisture from the air, reducing the need for water from their roots. On the other hand, if the humidity in the grow chamber is low, they will draw in even more water.

Because humidity affects how much water the plants drink and the amount of water you supply them, which contains nutrients, keeping humidity under control can give you more control over their nutritional intake.

Controlling the grow room humidity, on the other hand, is not only about preventing problems; having a balance and the correct grow room humidity make your cannabis plants stronger, have leafy plants, and have healthy and quality buds on your harvest.

What are the consequences of not having the proper humidity?

This is not meant to scare you, but we believe you should understand what’s wrong with poor humidity control in a growing environment. We realize how bad humidity is since we’ve dealt with all of these concerns ourselves.

Powdery Mildew ( White )

It is a fungal condition that occurs in high humidity environments. It can be tricky because new cannabis growth grows in wet environments. Fortunately, by ensuring a proper flow of air in your growing space, you may assist in reducing WPM; a simple oscillating fan – on such a surface level – definitely works.

Bud Rot

One of the worst circumstances that a cultivator can face is insufficient humidity regulation. Consider pulling a large, thick key cola from your crop only to discover the interior is white or gray with mold.

Nutrient Issues

Humidity in a growing environment is critical in determining how frequently your plants will drink. Your crops will be more prone to consume from their roots if the air in your room is dry. When they aren’t consuming enough due to higher temperatures, low moisture may allow them to ingest a lot of water from their roots and suck up a lot of nutrients.

Slow growth

Marijuana plants like more moisture when young and less moisture when old. They do not develop as rapidly or as fully as possible if these components are not there.

Humidity Basics

When growing weed, you need to maintain humidity, but you’ll never have the perfect humidity. Seed Supreme are here to help; please see:

  • 70% clones
  • 40-60% Vegetative
  • Flowering – 40- 50%
  • Final Weeks – 40-45%

Humidity measures how much water vapor is ‘kept’ in the air. Humidity can be calculated in three ways: total, specific, and relative.

When discussing humidity, most farmers prefer the RH (Relative Humidity) in the growing area. This relative humidity test compares the amount of water in the surroundings to the typical volume of water at that height. This is a quick reference for relative humidity’s many phases of a marijuana life cycle. We’ll go over each one in detail.


For clones, 70% RH is ideal. Building a water-intake root network takes time. New clones rely on leaf moisture from the environment, which is only possible at high temperatures. Requiring optimum humidity conditions would increase clone roots and young clone growth.

But you could also use the roots to water your crop. Leaves can pull water vapor directly from the soil, so higher soil humidity allows leaves to carry more water into the plant. Low humidity levels in the air may impede root formation.

Floral plants

Plants prefer 40-50 percent RH for flowering. The humidity should be lowered to 40-50 percent during the early flowering period. The technique requires caution because certain plants can be significantly stressed if the humidity is reduced below 40%. Reduce humidity gradually and observe how plants respond before introducing them to high-humidity environments.


This is particularly harmful during blossoming because it can form on or within your buds. If you find mold growing on your buds or rotting within, you must eliminate them immediately. Bud rot kills entire harvests, so keep an eye out for it spreading to others. If you can’t reduce humidity and have a mold pandemic, cutting your losses and harvesting immediately may be the best approach.

Even when the humidity is low, air movement around and through your crops is crucial. Small fans blasting over the crop canopy will help keep air moving because no wet spots grow through the crop.

Buds dying Humidity Treatment

Optimal drying humidity is 55% RH in the drying room. To protect the buds from drying too quickly, keep the humidity about 50%. This range is also great for preventing mold growth but not so great for drying for a beginner!

To boost the consistency of your healed buds, few farmers prefer to keep the humidity slightly higher. To avoid mold growth on your dried buds, use high humidity extraction!

Air ventilation is good in the drying area, so don’t squirt it directly on the plants.

What if it’s too cold?

Cooler seasons slow growth. Plants may be surprised or killed by temperatures below 60 °F (15 °C).


Because growing lights may become quite hot, and cannabis growth is typically constrained to relatively small places due to stealth or privacy concerns, many enclosed marijuana producers strive to associate with much too high temperatures and high humidity.

Workplace and growing area humidity are both affected by where you work. Fewer leaves and foliage in a small area allow moisture to accumulate.

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