Hi guys,
I run high humidity, but mainly because i can't help it (the high RH is caused by the plants).
I'd like to make one thing clear, some of the VPD optimal zones with temperatures 78-89 show best humidity in the 75%-85% area.
Reference: https://growingmarijuanaperfectly.com/2020/07/17/understanding-vapor-pressure-deficit-the-weird-humidity-puzzle-in-marijuana-growing/
Now everyone is so caught up with lower humidity during flower, thinking it's optimal and a lot of sites also suggest this. However in nature, during flowering humidity never changes. It's only optimal for indoors because we're all trying to prevent rot. However a lot of greenhouses aim for 70%+ humidity.
The rainforest and tropical countries also have many thriving plants in the high humidity ranges, whereas australia has a lot of plants which had to ADAPT to low humidity over thousands of years.
Source of optimal humidity : https://drygair.com/what-are-the-optimal-humidity-and-temperature-set-points-for-greenhouse-growing/#:~:text=The optimal relative humidity setpoint,growth and lower quality output.
Now these quotes from their references can explain this part for me:
"The cycle gets worse. Without the stomata and the cooling effects, the humidity in the environment gets lower. With less moisture in the air, the already overtaxed plant creates more issues. The good news is that constantly high humidity allows plants to keep their stomata open regularly because there’s no risk of losing moisture. ( Some Dutch scientists at the University of Wageningen in the Netherlands figured that out.)"
Also there are other studies that found stomata opening at 80% and closing at 20%. What's optimal ? Our chosen 50% in flower to prevent rot? or 80% with EXCELLENT airflow ?
source: https://www.grasscity.com/blog/post/what-are-stomata-and-why-should-you-care
Now finally,
We know when the stomata opens, it fills our rooms and raises the humidity. I have also in the past wondered why my humidity dropped 2 hours before lights off everyday! And the answer was I believe the stomata CLOSES, lowering my room humidity. Circled in red is the evidence from my data. Isn't it amazing knowing where the don't water 2 hours before lights off stems from.
Happy growing
EDIT: I'm blazed and dyslexic so if there's any typo atm, i cbf fixing it.
I run high humidity, but mainly because i can't help it (the high RH is caused by the plants).
I'd like to make one thing clear, some of the VPD optimal zones with temperatures 78-89 show best humidity in the 75%-85% area.
Reference: https://growingmarijuanaperfectly.com/2020/07/17/understanding-vapor-pressure-deficit-the-weird-humidity-puzzle-in-marijuana-growing/
Now everyone is so caught up with lower humidity during flower, thinking it's optimal and a lot of sites also suggest this. However in nature, during flowering humidity never changes. It's only optimal for indoors because we're all trying to prevent rot. However a lot of greenhouses aim for 70%+ humidity.
The rainforest and tropical countries also have many thriving plants in the high humidity ranges, whereas australia has a lot of plants which had to ADAPT to low humidity over thousands of years.
Source of optimal humidity : https://drygair.com/what-are-the-optimal-humidity-and-temperature-set-points-for-greenhouse-growing/#:~:text=The optimal relative humidity setpoint,growth and lower quality output.
Now these quotes from their references can explain this part for me:
"The cycle gets worse. Without the stomata and the cooling effects, the humidity in the environment gets lower. With less moisture in the air, the already overtaxed plant creates more issues. The good news is that constantly high humidity allows plants to keep their stomata open regularly because there’s no risk of losing moisture. ( Some Dutch scientists at the University of Wageningen in the Netherlands figured that out.)"
Also there are other studies that found stomata opening at 80% and closing at 20%. What's optimal ? Our chosen 50% in flower to prevent rot? or 80% with EXCELLENT airflow ?
source: https://www.grasscity.com/blog/post/what-are-stomata-and-why-should-you-care
Now finally,
We know when the stomata opens, it fills our rooms and raises the humidity. I have also in the past wondered why my humidity dropped 2 hours before lights off everyday! And the answer was I believe the stomata CLOSES, lowering my room humidity. Circled in red is the evidence from my data. Isn't it amazing knowing where the don't water 2 hours before lights off stems from.
Happy growing
EDIT: I'm blazed and dyslexic so if there's any typo atm, i cbf fixing it.
