Temperature and Humidity
Temperature and humidity share a single article as they are so closely linked. Generally, humidity in a growing context refers to Relative Humidity (RH). As temperature decreases the amount of water vapour it can hold before it condenses back into a liquid decreases. In other words, hotter air can hold more water vapour per volume than cold air can[1]. In fact, this is the principle that freeze drying relies on. Temperature and humidity can also be used to calculate the Vapour pressure deficit (VPD) which provides an indication to the cultivar's capacity for gas exchange.
Ventilation
Ventilation is a very important part of having control over the temp and humidity. In other words, a fan is crucial. Blower (centrifugal fans) should be used for this type of ventilation[2]
Vapour pressure deficit (VPD)
VPD is a metric to measure the difference (deficit) between how much water there is in the air (AVP) and the maximum amount of water the air can currently hold (SVP).
An excellent VPD calculator and chart of ideal VPD for each life stage can be found at dimluxlighting.com
Ideal conditions
The ideal temperature is range is 24°- 28°C[4] while the ideal humidity is 40-60%. Of course, the exact ideal values differ depending on the current life stages or the plant's genetics.
References
- ↑ https://www.royalqueenseeds.com/blog-indoor-cannabis-growing-relative-humidity-and-temperatures-n243
- ↑ Centrifugal Fan vs Axial Fan | Industrial Accessories Company - https://www.youtube.com/watch?v=gYxLbBP3evM
- ↑ L Breit, M Leavitt, A Boyd, Cannabis Science and Technology 2(2), 52-61 (2019). https://www.cannabissciencetech.com/view/circular-cannabis-systems-tracking-and-minimizing-waste-and-emissions-impacts
- ↑ Chandra et al. (2008) - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3550641/pdf/12298_2008_Article_27.pdf