cannabis growing indoor

Indoor Cannabis Growing: Ideal Temperature and Humidity Levels

cannabis growing indoor

Many people wonder “what are the optimum humidity levels for indoor cannabis growth?” The cannabis plants grow in a little warm temperature.

The growth of plants in indoor conditions depends on how the gardeners control the optimum growth parameters. Gardeners have to maintain the ideal temperature and humidity to maintain the quality of plants.

In this article, you’ll explore cannabis growth temp and humidity at each stage of growth. We’ll also discuss effective methods to control temperature and humidity.

What Cannabis Plants Need to Grow

The Cannabis plants also called marijuana or hemp are delicate flowering herbs. People used to smoke flower buds of female plants. The growth of cannabis plants has four stages which are germination, seedling, vegetative and flowering.  

The cannabis plants have medical importance. These plants are used in the treatment of pain, inflammation, cancer, gastrointestinal diseases.

The gardeners have to control the key conditions for the growth, some of them are: 

  • Medium: The cannabis plant requires more absorbent soil which allows the roots to grow and maintain the nutrient and water.
  • Lighting: The cannabis plants need 18 hours of light and 6 hours of darkness during vegetative period. 
  • Temperature: The cannabis plants require ideal temperature which ranges between 70-85 Farhenhiet during the vegetative period of growth.
  • Humidity: The best humidity level for growing cannabis is 40-70% RH.
  • Airflow: People introduce proper ventilation in their greenhouse for fresh supply of CO2 for photosynthesis.
  • Moisture: Plants need water for the growth and photosynthesis. Many gardeners ask “how many times the plants need water?” It depends on temperature, light and water-holding capacity of the soil.

Nutrients: The nutrient availability influences the growth and development of cannabis plants. You need fertilizers including macro elements and trace nutrients.

Why Temperature & Humidity Matters in Cannabis Growing?

Gardeners have to control the cannabis grow tent humidity levels. Because it impacts the respiration process. The dry conditions reduce the rate of photosynthesis as plants absorb excessive water from roots. 

The high humidity leads to spreading of pathogens. Maintaining cannabis growing humidity influences the production.

Factor

Why It Matters

Ideal Range

Too Low

Too High

Tips

Temperature (Day)

Boost metabolism

70–85°F

Slow growth

Heat stress

Use fans

Temperature (Night)

Affect flowering

58–70°F

Stunted growth

Stretchy plants

Maintain balance

Humidity (Seedling)

Support rooting

65–70% RH

Dry leaves

Mold risk

Use dome

Humidity (Vegetative)

Encourage growth

55–65% RH

Slow growth

Fungal issues

Add airflow

Humidity (Flowering)

Prevent rot

40–50% RH

Dry buds

Bud rot

Use dehumidifier

Air Circulation

Regulate climate

Continuous flow

Uneven temps

Mold growth

Use fans

Maintaining the right temperature affects the plant growth as well. High temperatures can cause stress, root rot and reduced growth. 

Similarly cold temperatures can reduce production and increase spreading of molds.

Poor temperature and humidity conditions cause lots of problems. The plants become dry if the pH is not maintained. The trichome of the plants becomes weak and gets separated from the plant.

High humidity levels lead to molds and microbial growth. Low humidity can lower the aroma and flavour of the indoor cannabis plants. The plant loses water faster than it absorbs. That’s why maintaining ideal humidity for growing cannabis is important as low humidity leads to leaf stress, poor growth and wilting.

Optimal Temperature and Humidity Levels at Different Stages of Cannabis

The cannabis plants have four stages of growth, mainly germination, seedling, vegetative and flowering stages. Each stage requires different humidity and temperature levels.

Seedling or Clone Stage

Seedlings require more hydration. Keeping the growing medium moist ensures that the plants are able to transpire. Low humidity causes dehydration and wilting of leaves. High humidity and temperatures mimic the plant’s natural habitat in a tent. 

Humidity 

65-70%

Day Temperature 

70-85°F

Night Temperature 

65-80°F

Vegetative Stage

Vegetative stage needs lower humidity than the seedling stage. Too high humidity can cause saggy roots, slowed transpiration and nutrient lockout. The roots absorb more water during this stage of growth.

Humidity 45-55%
Day Temperature 70-85°F
Night Temperature 60-75°F

Flowering Stage

The flowering stage needs low cannabis growing temperature and humidity. It is best to keep plants in cold conditions as the cold temperatures help bud color, density and the fragrance. High temperature can slow down the bud growth.

Humidity 

30-45%

Day Temperature 

65-84°F

Night Temperature 

60-75°F

Late Flowering Stage 

This stage requires lower humidity as it improves production, flavor and appearance. These conditions also prevent mold and bud rot.  

Humidity 

30-40%

Day Temperature 

64-75°F

Night Temperature 

60-68°F

Controlling Cannabis Growing Temperature and Humidity

Are you looking for methods to maintain cannabis grow room temp and humidity” Many gardeners struggle to maintain cannabis growing temp and humidity. Here is how to maintain the ideal temp and humidity for cannabis growing:

Tools to Control Temperature and Humidity 

  • Gardeners use many internet connected sensors. The sensors monitor temperature and humidity. 
  • Use automated climate control systems to adjust their humidifiers and HVAC. 
  • Record different plants’ growth and development with the help of data logger

Raising Temperature and Humidity 

  • You can use grow light to increase temperature at night.
  • Dehumidifier raises the temperature but reduces humidity.
  • Use a spray bottle for a cost effective method to raise the humidity levels.
  • Keep the soil moist to increase humidity.
  • Use space heaters to raise the temperature of the greenhouse. 
  • Humidifiers raise the temperature as well as humidity of the growth medium.
  • Hanging wet clothes and towels in the grow room maintains humidity.

Lowering Temperature and Humidity

  • You can remove the vent air to the outside to reduce the temperature. 
  • Use ACs and evaporative coolers on hot days. 
  • Turning off the light during the day decreases the temperature.
  • Proper ventilation helps the air to circulate better in the growing area.

Humidity Control with Coairo Grow Room Dehumidifiers

Coairo Grow Room Dehumidifiers can keep air fresh and humidity stable.

They remove excess moisture that fans can’t handle, preventing mold, root rot and pest problems. Designed for continuous performance, these dehumidifiers maintain ideal conditions for cannabis growth.

Visit Coairo.com to explore professional grade dehumidifiers made for modern growers.

Conclusion

Cannabis plants require ideal temperature and humidity levels for the growth and development. Low humidity levels lead to poor growth, low nutrient uptake and wilting of leaves.

Gardeners maintain ideal temp and humidity for cannabis growing with the help of different tools, technologies and processes. Humidifiers reduce temperature as well as increase humidity.

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