Starting to grow your own cannabis plants indoors?
Indoor cannabis cultivation is actually rising in popularity. More growers want to produce their own quality weed. However, healthy plants require dialing in two critical environmental factors - proper temperature and humidity levels.
Getting the temperature right is essential for cannabis to photosynthesize and develop well in each stage. Too hot or cold slows growth and leads to issues. Their needs change as the plants mature, so an understanding of the ideal temperature during seedling, vegetative, and flowering phases is key.
What's more, science tells us that temperature and humidity are closely linked. Warmer air holds more moisture. As temperature rises, humidity levels also increase.
Why does this phenomenon matter for cannabis growth? How does one keep temp and humidity levels optimal for cannabis growth?
That's what we'll explore in this article.
Why Temperature & Humidity Matter for Cannabis
When growing cannabis, temperature and humidity levels need to be closely monitored. They should be adjusted using stabilizers and similar instruments when needed. This will ensure optimal indoor growing conditions.
This is because cannabis is actually very sensitive to temperature and humidity levels. They need humid air to thrive. Their leaves easily lose moisture in dry air and their roots can't always replace it. Humidity delivers moisture to the plant tissues, preventing wilting.
But too much humidity isn't good, either. It encourages mould.
In terms of temperature, warmth fuels photosynthesis and growth. Cold slows metabolism. Cannabis plants thrive in specific temperature and humidity ranges. These ranges can change during different germination phases.
Regulating heat and moisture results in faster vegetative growth, bigger yields, and disease resistance. Since indoor gardens lack natural air flow, climate control is required to maintain ideal conditions for robust cannabis plants.
A proper indoor environment is critical for growing healthy, high-quality weed. The key is finding the ideal temperature and humidity balance to support healthy growth.
Ideal Temperature for Cannabis Growth
Early and careful climate management enables healthy sprouts to form and transition smoothly to the vegetative growth stage. That's why the seedling stage is critical for cannabis plants.
Luckily, indoor germination allows for more temperature control. Keep the surroundings warm to help the seeds sprout and protect the tender shoots emerge. But monitor the temperature closely, too. Excessive heat can damage the seedlings.
Seedling Phase
Ideal Temperature: 70-80°F | 20-25ºC
The seedling stage needs consistent warmth to sprout from seeds and support tender new growth. Temperatures shouldn't go above 80°F or 25°C since immature cannabis plants can't handle high temperatures yet.
Remember to monitor temperature levels closely - especially during hot days. Gently spray the seed trays with water if they start to dry out.
Vegetative Phase
Ideal Temperature: 75-85°F | 20-30ºC
The vegetative stage thrives during the day when lights are on.
Temperatures of around 75-85°F fuel rapid growth. At night, during dark periods, temperatures are typically cooler - around the 65-75°F range. This 10-15° drop tones the plants.
Monitor temperatures daily and utilize heating and cooling equipment like portable ACs and ceramic heaters to maintain this ideal day/night fluctuation. Proper ventilation and airflow are critical as well.
Flowering Phase
Ideal Temperature: 75-85°F | 20-30ºC
The last phase of the cannabis growth cycle is the flowering phase. During this phase, optimal temperatures are 75-85°F during the day and 60-70°F at night.
Warm days enable dense bud and resin production. The 10-15° cooler nights trigger hormone changes that boost flowering. Carefully monitor temperatures and make adjustments as needed.
A regulated, consistent environment results in the heaviest, most potent cannabis flower yields.
Ideal Humidity Levels for Cannabis Growth
Seedling Phase
Ideal Humidity: 65-75%
Cannabis seedlings thrive at higher humidity levels. Young plants need more atmospheric moisture while first establishing roots and foliage.
Use a humidifier if the grow area air is drier. A hygrometer is useful for monitoring humidity daily. Make adjustments as needed. Proper moisture minimizes wilting at this vulnerable stage.
Vegetative Phase
Ideal Humidity: 50-60%
During vegetative growth, lower the humidity to 50-60%. The cannabis roots have sufficiently developed enough to absorb plenty of water. Plus, the drier air strengthens stems and prevents fungal diseases.
Run a dehumidifier to remove excess moisture if needed to reach this ideal range. Some airflow from fans is beneficial as well for circulating the air.
Flowering Phase
Ideal Humidity: 50-55%
The flowering stage requires even lower humidity of 50-55% for optimal dense, resinous buds that resist mould. Drier air at this point is preferable. This encourages a higher terpene content, leading to a more aromatic and flavourful crop.
Monitor the crop closely with a hygrometer and use a dehumidifier if ambient humidity rises. Keep the lights-off humidity around 10% higher than during lights-on to avoid big swings.
Proper humidity management and the right equipment result in healthy cannabis plants resistant to pests and fungi. Make sure you track and adjust the moisture levels for each growth phase. Keeping humidity in the ideal range ensures thriving cannabis plants and abundant yields.
How to Maintain an Optimal Grow Room Environment
To grow healthy cannabis plants indoors, you need to carefully control the grow room environment. Remember that temperature and humidity levels are closely connected. Adjusting one impacts the other.
Here are some best practices for monitoring and maintaining an optimal environment for your cannabis:
- Use integrated controllers to automatically adjust heating, cooling, humidifiers, dehumidifiers, and fans to maintain optimal ranges.
- Ventilation is critical in a sealed indoor garden. Run oscillating fans 24/7 to circulate air.
- Exhaust fans remove heat and excess humidity. Stale, stagnant air encourages mould and other pathogens.
The proper controlled environment supports robust vegetative growth, abundant flowering, and high THC levels while preventing mould, fungi, and other crop diseases. Pay close attention to optimizing the indoor climate. It takes diligence, but the payoff is much healthier cannabis plants and premium buds at harvest.
Frequently Asked Questions
What should I do if the indoor temperature is too cold? What will happen to my cannabis plants?
Temperatures below 60°F slow cannabis plant metabolism and root growth. Anything below 50°F can be fatal.
Electric heaters raise temperatures quickly but use lots of electricity. Their drying heat makes humidity control hard, and uneven distribution doesn't warm all plants effectively. Small, efficient tubular heaters on the floor work well. Radiating cables are great for seedling trays.
Carefully regulate supplemental heat to keep your grow room in the ideal temperature range for thriving cannabis.
What should I do if the indoor temperature is too hot? What will happen to my cannabis plants?
Lowering heat in a grow tent or greenhouse can be challenging. Using fans to circulate air helps disperse heat and cool plants down. Installing an exhaust fan in the top vent removes rising hot air efficiently.
Cool mist humidifiers lower temps while adding moisture. Remember to monitor humidity regularly. Cannabis seedlings need higher levels than other vegetative plants.
With some key equipment like fans and humidifiers, you can regulate the temperature within the ideal range for healthy cannabis growth.
How often should I monitor temperature and humidity levels?
The best way to control the grow room environment conditions is to monitor both temperature and humidity at different times of day. Temperature and humidity rise together after the lights turn on as heat and transpiration occur, then fall after lights are turned off.
Aim to keep conditions very stable each day for vigorous, resilient plants. Fluctuations can cause stress to the plants, so track temperature and humidity over time to spot issues and make adjustments as needed.
Conclusion
Following optimal temperature and humidity guidelines for each growth stage leads to thriving cannabis plants indoors. Monitor levels consistently and make proper equipment adjustments to maintain the ideal environment.
With the right conditions sustained throughout the plant lifecycle, you’ll be rewarded with vigorous, high-quality cannabis.
