What Is The Best Temperature For Growing Cannabis?

Summary

This transcript delves into temperature management in cannabis cultivation, emphasizing the importance of maintaining warm conditions in the early stages to speed up growth and cooler temperatures in the flowering phase to enhance bud quality. The speaker explains the minimal impact of root temperature on overall growth, while also discussing the significance of day-night temperature differentials. Unlike other crops, cannabis thrives best with a zero differential, where the day and night temperatures are kept constant. These insights challenge common industry practices, focusing on optimizing shoot temperature for healthier, denser yields.

Takeaways

• 😀 Cannabis cultivation benefits from starting in warmer temperatures, around mid 80s°F (27-29°C), to promote quicker growth and light capture.
• 🌱 In early flower growth, cannabis performs better in slightly cooler temperatures, around mid 70s°F (24-25°C), to allow for denser, higher-quality buds.
• 🌡️ Temperature differences between the shoot and root are generally minimal. It’s more important to focus on optimal shoot temperatures while keeping root temperatures stable.
• 💨 During the vegetative phase, cannabis thrives in mid 80s°F to accelerate growth, and this can be maintained into early flowering (week 2-4).
• 🔄 A gradual decrease in temperature from the mid 80s°F to mid 70s°F during flowering helps ensure healthy flower development without rushing the process.
• 🌞 The typical practice of cooler nights and warmer days (day-night differential) seen in other crops may not be necessary for cannabis growth.
• 🌙 Negative temperature differentials (cooler day, warmer night) can stunt cannabis growth, reducing yield and overall plant health due to a decrease in photosynthesis efficiency.
• 📊 Zero day-night temperature differential (keeping temperatures similar during day and night) works well for cannabis and does not negatively affect growth or yield.
• 💡 Research on cannabis temperature management is still limited, and conditions for other crops do not necessarily apply to cannabis cultivation.
• 🌾 More controlled, consistent temperature cycles (without drastic day-night shifts) are optimal for cannabis flowering, unlike in floriculture crops where the opposite is often true.

Q & A

What is the general principle regarding temperature and cannabis cultivation?

Cannabis plants tend to develop more quickly under warmer temperatures, especially in the vegetative stage. This helps the plant spread out and capture light more efficiently. However, in the flowering stage, cooling temperatures can lead to higher quality flowers, as the plant matures at a slower pace, resulting in denser buds.

What is the ideal temperature for cannabis during the vegetative stage?

During the vegetative stage, cannabis plants thrive at around **mid-80s Fahrenheit** (approximately 29–30°C), which encourages rapid growth and better light absorption.

Why is it important to cool cannabis plants down during the flowering stage?

Cooling temperatures during the latter stages of flowering (around **mid-70s Fahrenheit**, or 24°C) help the plant mature more slowly. This slower maturation leads to denser buds and potentially higher-quality flowers.

What is the recommended day-night temperature differential for cannabis cultivation?

Cannabis plants do best with a **zero-day-night differential**, meaning the temperatures during the day and night should be roughly the same. This approach avoids stress and ensures consistent plant growth without negatively impacting yield.

How does the day-night differential affect cannabis growth and yield?

For cannabis, a **negative day-night differential** (cooler day, warmer night), which works well in other crops, does not provide any significant benefits. In fact, it may reduce yield, as the plant does not perform optimally with such temperature fluctuations. Maintaining a zero differential is optimal.

What happens when cannabis plants experience a negative day-night differential?

In cannabis cultivation, a negative day-night differential, where the day is cooler than the night, does not seem to result in more compact plants. Instead, it may lead to reduced yield due to lower leaf surface temperatures, which affect the plant’s overall ability to photosynthesize and grow efficiently.

Why might growers still use a 10°F differential between day and night for cannabis?

Some growers believe that a 10°F cooler night compared to the day might help cannabis become more reproductive and produce better yields, but this practice is not supported by the findings from the research discussed. In fact, the data suggests a zero differential is just as effective.

What is the relationship between root temperature and cannabis growth?

Root temperature has minimal impact on cannabis growth compared to shoot temperature. The focus should be on maintaining optimal shoot temperatures for the best growth and flowering results.

At what point during the flowering cycle should growers start cooling cannabis plants?

Cannabis growers can start to gradually cool the plants after the first two to three weeks of flowering. By week four, the temperature should be gradually reduced to enhance flower density and quality.

Can the use of a negative day-night differential in cannabis cultivation reduce the plant's growth rate?

Yes, using a negative day-night differential, where the day temperature is lower than the night, can stunt the growth of cannabis plants and potentially reduce yield. This is likely because the plant is not working as hard, which impacts overall growth and productivity.