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Crop steering with temperature for higher potency

Temperature controlled crop steering for enhanced growth and THC content

We recommend starting warm in vegetative stage with room temperatures of about 26°C or 80°F to maximise growth rate. Then reduce the temperature in early flowering stage to 20°C or 68°F keeping the bud temperatures down to preserve terpenes and cannabinoids such as THC.

crop steering cannabis with temperature control


Start warm and then reduce temperature in your grow room to increase terpenes and cannabinoids

Our understanding of the best methods for cultivation of medicinal herbs, particularly those that contain valuable cannabinoids such as tetrahydrocannabinol (THC), is becoming more sophisticated thanks to published research of extensive laboratory testing.

Crop steering, which involves manipulating environmental factors such as temperature, humidity, and light, has proven essential in maximizing both growth rates and THC content.

Of all the environmental factors temperature has the biggest effect on growth rate and potency.

This article explores how temperature-controlled crop steering can be utilized to boost growth in the early vegetative stages and increase THC content during the flowering stage.

We use data from the Crop Laboratory in Utah State university, run by Dr Bruce Bugbee. Dr Bruce Bugbee has published the results of extensive testing on medical herbs and is the best available source of new research in this area.

Temperature Control for Early Vegetative Growth

The vegetative stage is critical for establishing a strong, healthy plant structure that can support prolific flowering. During this stage, medicinal herbs benefit from a warmer temperature that supports fast growth. This pushes the plant to expand the canopy to fill the grow space and maximising the absorption of light.

Crop steering with temperature in the early stages of vegetative growth

Optimal Vegetative stage temperature range: Maintaining temperatures between 22-28°C (72-82°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.

Transitioning to the flowering stage

The flowering stage is where medicinal herbs focus energy on producing buds rich in cannabinoids like THC. It is best to reduce temperature to stimulate the plant to concentrate terpenes and cannabinoids in the flowers or buds as they are forming.

It is also important to note the Bud temperature will be higher than the room temperature by up to 5°C or 10°F. High bud temperatures will stress the plant and cannabinoids and terpenes will also evaporate.

The bud temperature will be much higher than the room temperature under HPS lights because they emit a lot of radiated heat to the plant canopy. .Bud temperatures will be lower relative to the room temperature with LED lights which barely emit any radiated heat.

Bud temperature is much higher than the room temperature, particularly under HID lights which emit a lot of radiated heat

If temperatures are too high in late flower the quality of harvest can be negatively effected as the flowers are too warm causing stress. Terpenes and cannabinoids are not preserved in the flower at higher temperatures.

Reduce grow room temperatures to increase cannabis potency and THC levels

Reducing the temperature mid way through the flowering cycle will maintain a better growth rate and preserve more terpenes and cannabinoids.

Initial Flowering Phase temperature range

 In the early flowering stage, maintaining slightly cooler temperatures around 24-26°C (75-79°F) during the day and 18-22°C (64-72°F) at night helps sustain vigorous growth and initiate bud formation.

Late Flowering Phase temperature range

 As the plants progress into the late flowering phase, reducing temperatures further can enhance THC in the harvest. Lowering nighttime temperatures to 15-20°C (59-68°F) while keeping daytime temperatures between 20-24°C (68-75°F)  stimulates the plant to increase resin production and reduces losses through evaporation.

Achieving Precise Temperature Control

We suggest using a thermal imaging camera or hand held Infra red thermometer to measure bud temperature in the flowering stage and manage your environment. 

Here are key strategies to achieve this:

  1. Run your lights at night time: The temperature is lower at night and even with lights and other equipment running the grow room should be cooler at night.
  2. Advanced Climate Control Systems: Utilize automated climate control systems that can regulate temperature, humidity, and CO2 levels with high precision. These systems should be capable of making real-time adjustments based on sensor feedback to maintain optimal conditions.

  3. Ventilation and Airflow Management: Proper ventilation is crucial for maintaining temperature and preventing mold and mildew. Use fans, exhaust systems, and air circulation equipment to manage airflow and distribute heat evenly throughout the growing area.

  4. Thermal Imaging Cameras: Regularly use thermal imaging cameras to monitor the canopy temperature of the plants. This technology helps in identifying areas that might be overheating or under-heating, allowing for timely adjustments.

  5. Data Logging and Analysis: Keep detailed records of temperature data and plant performance metrics. Analyzing this data helps in understanding how different temperature regimes affect growth and THC production, enabling fine-tuning of the crop steering strategy


Temperature-controlled crop steering presents a powerful method for enhancing the growth rate of medicinal herbs during the vegetative stage and increasing THC content during flowering.

By understanding the physiological responses of plants to temperature variations and employing precise environmental controls, cultivators can achieve superior growth and potency. Despite the challenges, the benefits of optimized growth and higher cannabinoid levels make this approach highly valuable.


2 thoughts on “Crop steering with temperature for higher potency

simon lane

Great reading, the 5 X5 array 5 stars.

June 10, 2024 at 13:50pm
Gerwyn Weaver

This is a very interesting thread indeed as i have found that if i don’t get my lady’s at 82-84c when the light is on they just don’t like it one bit! I know it has a lot to do with the space you have ( i have not got a lot but after i changed over to LED the first two grows where absolute disaster. Than one one the boys on a forum told me he had the exact same thing and instead of like with HPS you’re constantly fighting the heat he actually put a heater in and since then has not looked back. I suffer with epilepsy and all the different inflammation is great but with my mind it just turns into a mess. So this I find incredibly interesting and would love to hear more.🫵🏻😘👍🏼

June 10, 2024 at 13:50pm

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