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Humidity issue i can't correct!!!
- Thread starter Kalidaze
- Start date
South Sierra Dude
New member
I see good things only. Nice set up.
Last edited:
DrPhoton
New member
I did read it but just because you tried it doesnt mean it shouldnt work. Greenhouse growers dont give up once a outside condition reaches a certain level. They just use better equipment to compete with fighting conditions. Some greenhouse growers run their room through winters with heaters.
With respect to humidity and temperature that you asked, there are two main types of humidity measurements. Absolute humidity and Relative humidity. When temperature increases, the amount of water that can possibly be held increases because the space between molecules increases (lower pressure). When a enviroment with a specific amount of water has a temperature increase of 40°F the amount of water that can be held increases by 500%. But the overall water (absolute humidity) is the same, you only changed the space available for water to occupy. Again relative humidity is not linear like temperature, it is a relative percentage of the amount of water in the air compared to the maximum possible at that specific temperature and pressure.
What i would do personally is run a dehumidifer and ac in the room (i calculated your room at 1200 feet squared with a requirement of around 6 gpd, your dehumidifer seems to be on par with that). and seal your grow tent with a exhaust system (which you already have). When a pressure system with either positive or negative (it doesnt matter if static pressure is ideal) pressure is running, air is being replaced continuously so what happens outside happens inside. Trying to heat or cool or dehumidify inside while this is running is like trying to fly a kite against the wind. Greenhouse growers will deactivate or cycle their ventilation when operating these other systems. Leaving it on would vent any heat/cooling, dehumid or humid air.
Now i know you have already tried this so beer (gulp) with me. You used a dehmudifier, which worked, Great!. But the grow tent humidity stayed high. Well this could be because of either high evaporative sources from the tent such like the water growing system you have, or perhaps your venting system is not working properly or well enough. Or perhaps a combination of both. You also tried the dehumidifer inside, but like i have said, this is pointless as your venting out dry air and bringing in humid air from outside the tent.
So you have a solution that worked, you just have to find a way to get that solution to where you need it. If the ventilation system replaces the air fast enough you should have a humidity similar to outside the tent.
Things to try.
#Turn that ventilation system off and run the dehumidifer inside the tent, sealed.
#Keep the ventilation system running but try improve it with more powerful fans.
#Try turn your circulation fans off, having them on decreases negative pressure as it opposes the force of the fans.
#See if you can find a problem with the ventilation system that could be preventing it from replacing the air fast enough.
With respect to humidity and temperature that you asked, there are two main types of humidity measurements. Absolute humidity and Relative humidity. When temperature increases, the amount of water that can possibly be held increases because the space between molecules increases (lower pressure). When a enviroment with a specific amount of water has a temperature increase of 40°F the amount of water that can be held increases by 500%. But the overall water (absolute humidity) is the same, you only changed the space available for water to occupy. Again relative humidity is not linear like temperature, it is a relative percentage of the amount of water in the air compared to the maximum possible at that specific temperature and pressure.
What i would do personally is run a dehumidifer and ac in the room (i calculated your room at 1200 feet squared with a requirement of around 6 gpd, your dehumidifer seems to be on par with that). and seal your grow tent with a exhaust system (which you already have). When a pressure system with either positive or negative (it doesnt matter if static pressure is ideal) pressure is running, air is being replaced continuously so what happens outside happens inside. Trying to heat or cool or dehumidify inside while this is running is like trying to fly a kite against the wind. Greenhouse growers will deactivate or cycle their ventilation when operating these other systems. Leaving it on would vent any heat/cooling, dehumid or humid air.
Now i know you have already tried this so beer (gulp) with me. You used a dehmudifier, which worked, Great!. But the grow tent humidity stayed high. Well this could be because of either high evaporative sources from the tent such like the water growing system you have, or perhaps your venting system is not working properly or well enough. Or perhaps a combination of both. You also tried the dehumidifer inside, but like i have said, this is pointless as your venting out dry air and bringing in humid air from outside the tent.
So you have a solution that worked, you just have to find a way to get that solution to where you need it. If the ventilation system replaces the air fast enough you should have a humidity similar to outside the tent.
Things to try.
#Turn that ventilation system off and run the dehumidifer inside the tent, sealed.
#Keep the ventilation system running but try improve it with more powerful fans.
#Try turn your circulation fans off, having them on decreases negative pressure as it opposes the force of the fans.
#See if you can find a problem with the ventilation system that could be preventing it from replacing the air fast enough.
Royal Nugs
New member
If you're unable to control the humidity, I'd recommend topping or fim'ing them. Several times, so you have many colas. This coupled with strategic defoliation will keep the root rot monster away. This is all predicated on exceptional airflow through the plants. This becomes exceedingly important the later you get into flowering.
You wont get the massive colas but you should yield well. The additional trimming will be... uhh.. an adventure...yeah...
The addition of co2 would help on multiple levels but it depends on your budget. You stop using co2 during ripening, so the structure and airflow would still be important. It'd be a shame to grow some big boomers with co2 only to have them rot in the last week of flowering...
If you can get the humidity in check, disregard this
I have a friend who used desiccant packs as a filter for his fan driven intake into his tent. It dropped his humidity from 65 to 50 according to him. He got them from his work where they ship equipment and they put these big desiccant packs in the pallets to keep the equipment dry.
You wont get the massive colas but you should yield well. The additional trimming will be... uhh.. an adventure...yeah...
The addition of co2 would help on multiple levels but it depends on your budget. You stop using co2 during ripening, so the structure and airflow would still be important. It'd be a shame to grow some big boomers with co2 only to have them rot in the last week of flowering...
If you can get the humidity in check, disregard this
I have a friend who used desiccant packs as a filter for his fan driven intake into his tent. It dropped his humidity from 65 to 50 according to him. He got them from his work where they ship equipment and they put these big desiccant packs in the pallets to keep the equipment dry.
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Royal Nugs
New member
Ok. I thought you're supposed to cut it out last few weeks... I guess co2 would work then!
Green75
Guest
Co2 always works with a plant...some growers stop using Co2 late in flower because they believe at that point Whats done is done...as far as yield is concerned...I as usual disagree...the more Co2 a plant has the more all functions work better...within the plant ....the more they breath the more they swell/feed...
Royal Nugs
New member
You're naughty! Sinner!
Kalidaze
New member
Hello again Green75. I was wondering about that. I lowered my light and turned them up to 75% power (from 50%) once they fell over (from overstretching). They don't seem to be stretching anymore. Ph is around 6.0. I'm curious about the yellow new leaves as well. I've been asking around and searching but haven't gotten a definitive answer on that either. I plan on adding nutes soon.
PRIMO
New member
I'm not an engineer, but it seems to me that if room rh is 45 with dehumidifer and you vent tent into room with 420 fpm that should change the air 4x a min. I would try closing 4 of the five 6 in. inlets and put a 6 in. fan into the the last one pointing into the tent to help move 45 rh in and 75rh out. And if the temp gets to high turn on the a/c on cool setting.Also if you put the dehumidifier in the tent and it did'nt bring the rh down you need a new one.