What's the highest RH you've had during flower without mold?

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Edgar9

Well-Known Member
The title says it all. There seems to be a lot of different opinions out on the web about RH during flowering. Most people say keep it below 50%, where some say up to 60% is ok. I know there are a lot of variables such as air flow, bud size, strain, cleanliness of area, etc.

I've also noticed a lot of people have no idea what they're talking about. Lots of folks saying to raise the temps to combat humidity which is wrong. A higher air temp holds more water, thus raising humidity levels. An a/c tends to knock it down but all in all I'm at times reaching 60% during these late stages.

so,

Is 60% ok if you have big buds, all crammed together in a clean area, with lots of airflow?
 
Clown Baby

Clown Baby

Well-Known Member
And the answer is...*drumroll*

It depends.

It's all situational. If you have good airflow it should be alright, but cramped plants with that kinda humidity, you're playing a dangerous game. If you're still in early flower, consider using a sulfer burner, or spraying with powdered sulfer and water.

Thats called preventative maintenance!
 
polyarcturus

polyarcturus

Well-Known Member
filtered air, good swing between day and night temps and constantly moving air an you will be fine. i have fowered in 100% humidity b4 without mold,although iwould not recommend it.

just try to get it around 50% or below, not for growing reasons, but rather potency reasons
 
A

astroastro

Active Member
Edger9- you are wrong in that raising the temperature of a given space will, in fact, lower the relative humidity. Water vapor 'displaces' the other constituent elements of atmospheric air- warmer air has a higher capacity to hold water vapor because the other elements of the air will be farther apart, thus the relative humidity of any given body of atmosheric air will be higher at cooler temperatures and lower higher temperatures- assuming no additional water vapor is added to the system. Temperature and relative humidity always work in inverse proprtion to each other.

Think of air at the surface of the earth- the sun comes up, heats the ground which heats the surface air, it rises. Because the upper atmosphere temps are much colder then the surface, the space between air molcules gets closer as they cool, squeezing out the water vapor. Water vapor condenses, a cloud is formed. Air that, at the surface was at, say 60% RH is now at 100% RH- a cloud is super saturated with water vapor. The primary difference is the air temperature.

Raising the grow room temp will in fact lower relative humidity, but has other consequences that should be considered carefully. It is probably not the best solution.
 
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