Growing temperature is very important to encourage photosynthesis and promote the health of cannabis plants, especially in grow rooms. Improper temperature can make or break a crop and should be very carefully monitored throughout the plants’ growth cycle.
Temperature and Cannabis Plants
The temperature at which a cannabis plant is grown is vital to the health of the plant. Temperature affects internodal growth, the rate of water absorption, respiration, and the PH level of the growing medium.
Sometimes even small variations in temperature over long periods of time can stunt growth and cause long-term problems in root growth.
Changes in temperature can also be used to simulate nighttime as well as a tool to trigger flowering.
Ideal Temperature In Your Cannabis Grow Room
A standard, well ventilated grow room should be kept between 75-85 degrees Fahrenheit under optimal conditions.
Temperature can be raised or lowered according to your plants’ needs. For example, if you’re providing extra CO2 to your plants, your cannabis grow room temperature should be raised to 86-90 degrees for efficient absorption.
“Nighttime” temperatures should be slightly lower at about 71 degrees to prevent stretching but ensure your plants “sleep” and recover.
Measuring Temperature In Your Cannabis Grow Room
It’s best to measure the temperature in the shade of your grow room, as well as in several different locations.
Using a digital thermometer with a separate sensor will allow you to measure temps from outside of the grow room while the lights are off.
Lowering the Temperature Of Your Cannabis Grow Room
HPS and other high output lights can produce far more heat than is safe for the survival of your cannabis plants.
Always run an extractor fan when using these lights to circulate and pull heated air from your grow room.
If your lights have ballasts or generators, keep them outside the growing area if possible.
You might also consider air conditioning units, but only as a last resort as these can drastically increase your overhead costs.
Increasing the Temperature Of Your Cannabis Grow Room
You’ll rarely need to increase temps during “day” hours, as the lights typically are sufficient. At night, you can hold heat in your space by shutting off the extractor fan.
You may need to add a simple space heater or radiator to supplement nighttime heat, though these can be costly to run.
Monitor the temperature of your grow room carefully (both day and night) and adjust the heat accordingly for maximum efficiency.
The botanical experts at SoHum Living Soil know all of the best practices when growing cannabis. Let us share our knowledge with you by clicking through our articles on the subject or stop by our store in Denver to speak to our knowledgeable staff.
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FAQs
For most grows, the ideal temperature range is between 65-80°F (18-26°C). Keeping temperatures within this range helps maximize plant growth and development and contributes to large and healthy buds.
What is the best soil temperature for cannabis? ›
Never place constant and direct fans aiming toward plants. Soil Temperature: Ideal soil temp is 68°. It can fluctuate but should average 68° for best nutrient uptake. Humidity: Ideal humidity for flower is 40-60% and for vegetative growth it is 60-80%.
What is the best climate for indoor cannabis? ›
Indoor Growing Environments
Generally, pot plants in their vegetative stage prefer a temperature in a range from about 68 to about 77 degrees Fahrenheit. When they are flowering, cannabis plants like a range of about 65 to 85 degrees Fahrenheit.
What temperature should cannabis water be in soil? ›
When watering cannabis grown in soil, your ideal temperature is between 65 and 73 degrees Fahrenheit. Water that's higher in temperature, like your pasta rinse, or that excess from the summer bird bath, will be lower in oxygen. Roots will struggle more to take in what they need and pass it along.
What is the correct temperature for a living room? ›
The best room temperature for your living room
Most people find the ideal temperature in the living room to be between 19 and 22 degrees. Others believe 'the warmer the better', of course keeping in mind that every degree will also be seen on the bill. Preferably, do not heat to more than 20 or 21 degrees.
What temp is too cool for indoor plants? ›
Snake Plant (Sansevieria): The ubiquitous snake plant is a tremendous houseplant that will survive almost anywhere. It will take low light, cool temperatures, and dry soil very well. Dracaena (Dracaena marginata): Dracaenacan also handle cooler temperatures with ease. It can withstand temperatures of 50 degrees F.
Is 65 degrees too cold for cannabis? ›
The ideal daytime range in flower should be between 72 and 85°F, while the room can drop to as low as 55 to 70°F at night.
What are the growing conditions for indoor cannabis? ›
Ideal Cannabis Growing Environment
- Temperature Range: 72-82°F during lights on and 66-70°F during lights off.
- Root Zone Temperature: 67-68°F.
- Room Humidity: 40-60%
- Light Cycle Length: 18 hours on, 6 hours off during vegetative growth; 12 hours on, 12 hours off during flowering.
The ideal cannabis flowering humidity is between 40% to 60%. During flower, lowering your relative humidity level can help prevent mold and mildew from forming. To accommodate the lower RH, cooler temperatures will also help you maintain your ideal VPD.
What temperature is too hot for cannabis plants? ›
In the vegetative stage, cannabis plants thrive in a daytime temperature range of 24-32°C (75.2-89.6°F). This warmth supports vigorous growth and development. However, once the plants enter the flowering stage, the temperature should not exceed 28°C (82.4°F), with some tropical strains being the exception to this rule.
Feed requirements will vary as the plant matures. Some guiding principles are: Nutrients or plain water: For coco and Rockwool, use nutrients at each watering. For soils with high capacity to retain nutrients (high CEC), it may be beneficial to use nutrients at just each alternate watering.
What are the signs of cold stress in cannabis plants? ›
Temperatures that are either too high or too low can cause heat and cold stress, both of which greatly affect the health of plants. Cold stress will cause plants to droop and eventually wilt—side effects of the plant's inability to absorb nutrients and water to stay alive.
What is the best room temperature for growing plants? ›
Maintaining temperatures between 20-28°C (68-82°F) during the vegetative stage promotes vigorous growth. Warmer temperatures accelerate metabolic processes, including photosynthesis and nutrient uptake, leading to faster growth rates and stronger plants.
Where should a thermometer be placed in a grow room? ›
The key areas are: Canopy level: Near the top of your plants, at the level of the uppermost leaves. This helps in monitoring the temperature that directly affects your plants. Root zone: Near the soil or growing medium.
What temperature should LED grow room be? ›
Thus with light sources rich in IR, an air temp of 78F is functionally 83F-85F to the plants metabolism. LED's emit no IR, so to achieve similar metabolic rates found in HID or greenhouse conditions at 78F air temp,LED growers need to run the room air temp at 83F-85F.
What temperature should a plant room be? ›
Most houseplants thrive between 65 and 75°F (15-24°C) during the day and 60-68°F at night. But remember that the thermostat temperature in your hallway won't be an accurate representation of the temperature in other rooms so use your common sense.
