humidity question

Botany101

Botany101

Active Member
ive never had to deal much with humidity, correct me if im wrong but arent the humidity levels soppose to be around 40-50 or so during flowering?
at lights off my humidity is rising, when i checked it today the humidity had risen to 68
what should i do to solve this?
 
Just vent the air, unless the RH is also really high.

Humidity can be really hard to adjust - if you are running a co2 gen you can't just exhaust the air, because then your co2 gen runs non-stop.

You might want to describe your setup a little - you got a tent, a room, a basement, temp / humidity outside, ect?
 
Btw - you want to watch the humidity over a few days and during different times of the day. There can be a lot of things that cause it to fluctuate, including the weather.
 
Relative humidity of 68% with lights off isn't so bad as I understand it. The main reason you want to keep humidity down is to avoid mould and mildew problems. So long as humidity drops well below 68% daily during lights-on (vents on) then you shouldn't have problems. Consistent relative humidity above 70% in a warm room is where you start to risk significant mould growth, though the danger point is lower in a colder room as it's not high relative humidity but high water vapour pressure that allows mould and mildew to grow. How cold does your room get during lights-off?

Supposedly a plant will produce more resin if it grows in dryer air, as the plant produces extra resin as a kind of 'chap stick' to help keep the moisture in in a dry climate. That said, there are plenty of growers living in humid climates that manage to produce good smoke with RH values regularly exceeding 80% - you just have to be very vigilant to ensure mould doesn't take hold. If you're worried a dehumidifier will suck moisture out of the air in your grow space and keep everything nice and safe.
 
I feel that the optimal RH range is from 30-45 for flowering and 50-70 for veg, great results with frosty buds!
 
yah my RH levels during lights off gets into the high 60s rite around where the humidity jumps to but when lights are on it only drops to between 50 and 60, i got pretty damn good ventalation goin, by the way its a closet grow in a 5 ft by 4 foot room or so, (not very big) but i got ducts goin threw the walls an shit so most of the time the door is closed off but i open it for fresh air daily, im using 6" 250 cfm fans with all my venting, going in and out. only way i could think to get better ventin is higher cfm fans but im kinda low on money at the moment.
with lights off my temperature drops to about 69-71 degrees and with lights on it stays between 75 and 80 or so.
i just went an checked on the temps and the humidity is at 51 rite now an the lights have been on for about 3 1/2 hours, RH is at 61.
i mite just be able to find a dehumidifier to fix everything, mold is the lasssssttt thing i want on my buds
 
it has been raining nonn stop everyday pretty much for the last month so im sure that has to do with some of it, good point
 
40-60% for flowering. personally i perfer anything under 50 as it discourages mold and all kinds of bad shit from growing, so i keep it between 40-50 at all times during my flowering cycle
 
a dehumidifier will lower your humidity and also raise your temp in the room. for that reason i need to run my dehumidifier at lights out. i also set it to 35-40% the last couple weeks.
 
I run my dehumidifier at almost continuous it auto shuts off, it does increase temp up but manageable, im still able to get a temp drop for night time with it running. 81/73. As the temps outside starting to cool down, it will help out with temps and my electricity bill! Im pushing $300 a month now, and only a 400W light....those greedy bastards!
 
MrBosco said:
Relative humidity of 68% with lights off isn't so bad as I understand it. The main reason you want to keep humidity down is to avoid mould and mildew problems. So long as humidity drops well below 68% daily during lights-on (vents on) then you shouldn't have problems. Consistent relative humidity above 70% in a warm room is where you start to risk significant mould growth, though the danger point is lower in a colder room as it's not high relative humidity but high water vapour pressure that allows mould and mildew to grow. How cold does your room get during lights-off?

Supposedly a plant will produce more resin if it grows in dryer air, as the plant produces extra resin as a kind of 'chap stick' to help keep the moisture in in a dry climate. That said, there are plenty of growers living in humid climates that manage to produce good smoke with RH values regularly exceeding 80% - you just have to be very vigilant to ensure mould doesn't take hold. If you're worried a dehumidifier will suck moisture out of the air in your grow space and keep everything nice and safe.
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What he said.
 
i think i found a pretty good dehumidifier that im gonna use so i should be straight. im not to worried about the temperature tho because it stays in the mid to low 70s with the lights on so it shouldnt get to much warmer, thanks for all the good advice now i know rite where to keep my levels at now. ill be straight for the rest of my grow
 
Botany101 said:
i think i found a pretty good dehumidifier that im gonna use so i should be straight. im not to worried about the temperature tho because it stays in the mid to low 70s with the lights on so it shouldnt get to much warmer, thanks for all the good advice now i know rite where to keep my levels at now. ill be straight for the rest of my grow
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if your running at 70 degrees and your dehumidifier has to run for lets say to drop the humidity aroung 25%, then your temp will raise to about 85 degrees or maybe more.
 
damn alrite well ill get the dehumidifier in there an see how high the temp raises, maybe i can find a small dehumidifier or something that will make less heat
 
Botany101 said:
damn alrite well ill get the dehumidifier in there an see how high the temp raises, maybe i can find a small dehumidifier or something that will make less heat
Click to expand...

Best bet for temp issues is get ahold of some dessicant and put it in cheesecloth type mesh bags, hang it around the plant site and that should help out with your humidity, combined with the dehumidifier! You can build a makeshift vent to exhaust the heat from the dehumidifier.
 
thats a really good idea! im gonna look into the dessicant and get some of that on my hands, the makeshift exhaust vent is very clever idea thank you
 
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