Is high humidity at night bad for cannabis?
Gabriel_ODstarted grow question 4y ago
During day, I can maintain the grow room temperature to 75-77'F and humidity 55-65%. But at night, temperature raised up to 77-80'F and humidity up to 70-80% because I closed vents and air condition. Could this effect my plants in long term? Should I open vents at night also?
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Setup. Ventilation
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Sciolistic_Steveanswered grow question 4y ago
65 and below is better. Lower than 65 definitely safer for late flower. That's when you have highest risk of microbial growth due to RH%. More plant material bunched up with less airflow, etc etc.
one or two nights may not be an issue.. Keep eye out for bud rot if it continues... remove larger area than visible rot. pray it didn't spread elsewhere.
It also impacts VPD in plant, which impacts rate of uptake of water. this could impact how concentrated you want your fertilizer. if it speeds up, you need to dial back a bit and vice versa if it slows down in the case of high RH. Temps are part of this equation too.
def open vents at night if it reduces RH without too large of a drop in temperature. 70-80% is damn near an incubator for microbial growth with warmer temps.
Pjm70answered grow question 4y ago
You will probably be ok in veg, when in flower the humidity should be lower
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ChitownCannaChicaanswered grow question 4y ago
It’s bad for powdery mildew and bud rot—- air flow and vpd are key! I would try and get those numbers down myself…
If it’s not possible—- add a fan or two!
Good luck
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Kush_queenanswered grow question 4y ago
While your in veg you won't have a issue but in flower you will risk budrot I use a fan pulling cool air in and one pulling stale air out and circulating fan ventilation is key
Good luck with your grow 💚
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