Humidity levels in tents

I’m in late veg and all of a sudden I’ve had abit of a spike in humidity today and yesterday, my exhaust is regulating the humidity and keeping it at 70% because that’s what I have set my high RH to be to trigger exhaust fan speed increase, my real question is, is 70% RH in late veg a little to high? I definitely know it’s at the high end of recommended RH for late veg but I’m wondering if I should set her to a little lower to bring it down or not worry, The spike in RH is most likely from the intense watering I did a couple days ago because I let them dry out a little and did a big flush.

I would be uncomfortable with a constant 70% rh in late veg. How is the airflow/fan setup inside the tent?

madvillian420 said:

I would be uncomfortable with a constant 70% rh in late veg. How is the airflow/fan setup inside the tent?

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Air flow is fine could probably do with another fan won’t lie, humidity was always sitting around 55 60 range then yea watered them and huge spike hoping it drops a little it the coming days, some of the plants have water pooling on there leaves ? Are they sweating or is this moisture from the air settling on them?

madvillian420 said:

I would be uncomfortable with a constant 70% rh in late veg. How is the airflow/fan setup inside the tent?

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When I open the tent door my rh drops down to around 60 I might just leave the door open and let them breath a little

Novicegardner said:

When I open the tent door my rh drops down to around 60 I might just leave the door open and let them breath a little

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are you running lights 24/7?

Novicegardner said:

When I open the tent door my rh drops down to around 60 I might just leave the door open and let them breath a little

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not a bad idea, i open mine a bit in veg all the time for airflow

madvillian420 said:

I would be uncomfortable with a constant 70% rh in late veg. How is the airflow/fan setup inside the tent?

Click to expand...

madvillian420 said:

are you running lights 24/7?


not a bad idea, i open mine a bit in veg all the time for airflow

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Nope 18/6 I have just check the humidity level outside today and right now it is sitting at 77%!! have had a warmer day today for it being end of winter and now have abit of a storm rolling in so not really much I can do for myself right now! Other than wait for the temp to drop a little this late arvo and abit of a lower RH level, don’t have a dehumidifier on hand so is what it is for now !

madvillian420 said:

are you running lights 24/7?


not a bad idea, i open mine a bit in veg all the time for airflow

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Thinking I might try seal my room up a little as it is in the garage and taking the air from outside in if I can seal the room the RH should drop a little just for today only have fresh air coming in is under the door so might just chuck a towel down and plug her up see if it help

I have just looked at the forecast for the week and the humidity levels are going to be very very high for the next few days from high 70s to low 90s wish my luck looks like I’m gonna need to get me another fan and a dehumidifier was really hoping to not since the dehu is gonna suck a lot of power and there isn’t much room in the tent already can anyone recommend a good low wattage dehumidifier with a largish res or is there anyway to customise the res size on a smaller one?

If humidity is high already in the air going into the tent its going to be gard to control. Remember that for a given amount of water in the air RH goes down as temps increase, you can reduce RH by adding heat to your tent.

Rocket Soul said:

If humidity is high already in the air going into the tent its going to be gard to control. Remember that for a given amount of water in the air RH goes down as temps increase, you can reduce RH by adding heat to your tent.

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Yes I have just gone in there and turned up the heater I also added a larger house fan i Weber I had lying around in the Garage for more air flow and it has worked wonders! Got the RH back down to 55 the plants where looking very very sad when I went in there 10 minutes ago hopefully they recover I was planning on flipping them in a weeks time do you think they will be okay? The temps got down to about 21 and RH was at 70 for a good few hours ? Would that be enough to stunt them? They are fully established late veg plants so I’m hoping they bounce back fairly quickly

I wouldnt think it should stunt them but dont put them into flower until you can see the plants happy, always look at your plants first and then on your environmental parameters.

Since environment is so important with led plants it might be a good idea to try out what environment is like in your tent when the light is on full power; that way you know already how to adjust environment before you get stuck into flower.

I would not be worried about 70%rh , unless the temp is very low. I am around 70% thru half of flowering, intentionally. Look up a vpd chart and try to keep it in range.

Novicegardner said:

some of the plants have water pooling on there leaves ? Are they sweating or is this moisture from the air settling on them?

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That is usually from the leaves touching and not having enough space to breathe. I'd pluck a couple to free up space if you see it happening in the same spot(s) repeatedly. Thats an indicator of a"dead zone" of no/inadequate air movement and isnt ideal.

Since you are doing 18/6 you will have a considerable spike ^ in humidity every day at lights off for those 6 hours. Are you seeing 70% with the lights on? If so what is it when theyre off? Hopefully your hygrometer has a high and low. mine records the highest and lowest points of RH% and temps reached within a couple days and has it constantly displayed.

I wouldn't stress in veg as long as you have good internal airflow. Some preventative defoliation probably wouldn't hurt. I'd be very worried with that humidity level in flower, though.

madvillian420 said:

That is usually from the leaves touching and not having enough space to breathe. I'd pluck a couple to free up space if you see it happening in the same spot(s) repeatedly. Thats an indicator of a"dead zone" of no/inadequate air movement and isnt ideal.

Since you are doing 18/6 you will have a considerable spike ^ in humidity every day at lights off for those 6 hours. Are you seeing 70% with the lights on? If so what is it when theyre off? Hopefully your hygrometer has a high and low. mine records the highest and lowest points of RH% and temps reached within a couple days and has it constantly displayed.

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I have a hydrometer in there and it does display highs and lows will check after work my aci controller also does will check that too to see how accurate things are looking, in all honestly I think I was lacking air circulation in the tent I had one small clip on fan running in there and while it was fine while the plants where smaller they are a little larger now and are needing more, as soon as I put the larger fan in there as well humidity started to drop straight away check on them this morning and it’s sitting at 60% again, 70 was far to high the plants visually where not liking it starting to wilt and thinner stalks where dropping, check this morning and they are all standing up proud again at 60%