can ventilation overcome 71 rh during flowering

My room gets to 71% rh while the lights are off but drops back to high 40's low 50's while the lights are on. I was wondering if anyone had any insight to air circulation effecting the chances of bud mold in these strains (island sweet skunk, g13, biodiesel, nyc diesel, lime green skunk, agent orange) given those conditions?

freshenstien said:

My room gets to 71% rh while the lights are off but drops back to high 40's low 50's while the lights are on. I was wondering if anyone had any insight to air circulation effecting the chances of bud mold in these strains (island sweet skunk, g13, biodiesel, nyc diesel, lime green skunk, agent orange) given those conditions?

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do you have a fan on when lights are off? If not try leaving one on and see. I have grown Island sweet skunk for over a yr. now, dont have to worry about mold with it. Flower time 70 to 80 days. Topping makes it like you more. Scrog or heavy lst is what it wants, if inside.
Last 20 days of flower watch for light burn.

@freshenstien you are correct, it will increase drastically chances for bud rot. It is good you caught this. pls read this: http://stuffstonerslike.com/2011/09/ending-the-bud-rot-blues/

@mike4c4 is correct, some strains will resist bud rot.....

why does the RH drop when the lights are on? Because your venting system turns on when the lights turn on? and it is off during dark?

Start pulling more negitive perssure threw the grow .

Tone550 what do you mean? I'm sorry I don't understand.

And the temp just goes from 68 in the dark to 72 to 75 when the lights are on. I live in a cold place and high altitude 10000ft. I have 2 1000 watt hps n a 66 can filter that has a 6 in inline rated 370 cfm that sucks air straight out of the room and I have a 16 in oscillating fan (filter and fan run 24 hrs)

Sorry about the quality but it's a little peak at them.

The capacity of the exhaust should be roughly 3 times what you got now with 2x 1000watt. Especially with a carbon filter yours is more suitable for a single 600watt setup. And yes, that makes a major difference as long as the air you suck in is less humid. Like Tone said, increase negative pressure, ie. suck more air out of it faster, upgrade your ventilation system.

paint your walls white !!
bare wood holds moisture

just saying

thanks for the reponses folks that's a tremendous amount of help! I don't have any mold issues at the moment I just wanted to be proactive about keeping optimal conditions for the ladies.

freshenstien said:

thanks for the reponses folks that's a tremendous amount of help! I don't have any mold issues at the moment I just wanted to be proactive about keeping optimal conditions for the ladies.

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I like to run my flower around 45% but I do not stress over it as long as I have it below 60 with a small fan blowing threw canopey gl bro

Anything above 60 is in the 'mold zone' big time. Run a dehumidifier at lights off or get moldy buds.

This is a question that might help the OP: can't you just heat the room up during lights-off time to drop the RH? Im in a similar situation, and wikipedia says the higher the temperature the lower the RH for any given amount of moisture in the air.

EDIT: (IGNORE ME - Im clearly an idiot)

Chester da Horse said:

This is a question that might help the OP: can't you just heat the room up during lights-off time to drop the RH? Im in a similar situation, and wikipedia says the higher the temperature the lower the RH for any given amount of moisture in the air.

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Yea if you wanna grow black mold heat is not a solution , stronger ventilation or a dehumidifier is .

Tone5500 said:

Start pulling more negitive perssure threw the grow .

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"negitive perssure" is a result poor airflow, the exact opposite of what he needs

Chester da Horse said:

This is a question that might help the OP: can't you just heat the room up during lights-off time to drop the RH? Im in a similar situation, and wikipedia says the higher the temperature the lower the RH for any given amount of moisture in the air.

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RH = relative, it's the % of the max amount of water the air could contain at a temperature. Warmer air has a higher water potential, which is the thriving force for plants. The air has a higher water potential than the leaves, so water is sucked out the plant, which in turn sucks up water and nutes. Warmer air allows for more water in the air and increases the transpiration rate. If you don't exhaust that properly (outdoors unless you want to mold up your home) it's not a solution at all. I actually love winter grows because it's much dryer then. Low temps in combination with high humidity should be avoided, but raising temp alone isn't going to solve the humidity issue.

you can increase air flow from outside the room.But if the humidity level from outside is high,over 60% it will do you no good,
The warmer the air the more moisture it will hold,
when lights go off the temperature may drop,if it drops below the dew point humidity will spike,this happens when the lower temp reach's the dew point the air will want to give up its moisture,called condensation,
the moisture will fall out of the air on lay on the floor and plants,The plants for indoor growing actually dig it,
it simulates what would happen in nature,
you best bet to control humidity is a dehumidifier,or lower the temp of your room so the air does not hold as much water and the air conditioner runs more frequent removing moisture from the air,
was going to post a psychometric chart,but unless you are a mechanical engineer not much chance in most people understanding it,
a dehumidifier 70 pint one is around 200 bucks depending on where you get it from.It will pull around 7.5 amps of power 120 volts,make sure you do not over load your circuits.
good luck

Tone5500 said:

Yea if you wanna grow black mold heat is not a solution , stronger ventilation or a dehumidifier is .

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Like. Thanks bro, just learnt something important! nice to have wiser heads around to correct noob-arsed suggestions like that

So will ventilation solve? Yes, IF< the fresh air has less humidity. Some things that solve light time humidity.

- all damp items out
----funny how many times I will find a cleaning cloth or sponge that gets wet with the daily feeding.
- all damp that can't go out is sealed
----as the day temp increases, my water tubs and barrels will contribute to humidity
- cover media around plants and the containers with mylar bubble wrap to keep the wet media cooler to lower evaporation.
- set up racks of calcium carbonate and collect the drip water in a sealed container.

Ok plain and simple you live in a dry area such as I you can drag air threw your plants and ventilat into attic like I do witch is also ran on a ventilation system. Or to the outdoors . Or if you live In a humid area like Florida is in the states get a dehumidifier gl again bro

I just saw some dehumidifying cans at tractor supply last night. You just set them out and they draw moisture. I'm sure other places sell them.