Growers always strive to produce the best cannabis, in all aspects. To grow large, high-quality buds, with the right concentration of cannabinoids and terpenes, all while avoiding mold at all costs. In order to achieve these goals, it’s often necessary to utilize controlled environments, such as greenhouses, indoor grow room, or even grow tents. It’s then possible to control all environmental aspects, including:

• Lighting
• Temperature
• Humidity
• Airflow
• Carbon Dioxide (CO₂)

Cannabis Temperature Control

Like all plants, cannabis likes comfortable temperatures. 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.

Ideal Humidity Range for Cannabis

Cannabis has an ideal humidity range, just as it has an optimal temperature range. Most cannabis growers prefer a range of 40-70% relative humidity, depending on the growth stage. In terms of VPD (vapor pressure deficit), the ideal range is 0.8-1.1 kPa during the growth stage, and 1.0-1.5 kPa during flowering stages.

Preventing Molds and Mildews

While the ideal humidity range has a huge impact on development, it’s not the only reason to control humidity. Perhaps the biggest issue with humidity is mold. The most common of which being bud rot (also known as gray mold or botrytis) and powdery mildew.

Utilizing Airflow to Improve Cannabis Cultivation

Air movement is especially important when it comes to cannabis plants. Indoor cannabis grows are usually crowded, with thick canopies almost overlapping. Add in the fact that cannabis buds are extremely dense, and you get much higher humidity levels inside the foliage and buds, than the rest of the grow space. This is where airflow comes in to play.

Improve Cannabis Growth with CO₂

Carbon dioxide is a key element in photosynthesis. So, when there’s enough light, and an ample supply of water, increasing the CO₂ concentration in the space can drastically improve photosynthesis. Of course, better photosynthesis improves development and growth. The average CO₂ concentration in the environment is about 400 ppm (parts per million). However, indoor cannabis grows may reach as much as 1,000 ppm, by injecting compressed CO₂ into the space.