High Humidity Argh!

Ok, this is our first hydro grow and we are having MAJOR humidity problems. Our lights are on 7p-7a, we are using CO2, a carbon filter, and fans both at the top of the canopy as well as at the height of the pots. We water every hour that the lights are on and we have a 600w lite in an air cooled hood.

SO, now our problem is that the humidity is registering above 70% when the room is closed. When we opened the room this morning, there was condensation on the walls and the res.

Any ideas on getting the humidity down?!?

The easiest way is with a dehumidifier, but they can generate lots of heat. The heat may not be such a huge issue for you as you are injecting CO2.

you can buy stuff for storage units like what they throw in bags of food... those small bags of celica moisture collecting stuff.... you can use that in a big box and it will soak alot up i use it in my basement grow room. also dehumidifiers.... ahh you can do things like keeping a fan blowing to help dry it up....

What size room and what size exhaust fan do you have? Your vent system might not be able to handle the sweet stinky heavy ass air. Quick fix would be to buy a dehumidifier and a humidity controller. Dehumidifiers are pretty cheap if your grow area is small and for around 70ish bucks total you could rig up a humidistat to control it. http://www.amazon.com/dp/B000H0XFCS/ref=asc_df_B000H0XFCS1557449?smid=ATVPDKIKX0DER&tag=hyprod-20&linkCode=asn&creative=395093&creativeASIN=B000H0XFCS &
http://www.globalindustrial.com/p/hvac/controls/thermostats/honeywell-low-voltage-spst-manual-humidistat?utm_source=google_pr&utm_medium=cpc&utm_campaign=Thermostats-google_pr&infoParam.campaignId=T9F&gclid=COaRrf7YgKkCFcLr7Qodg11ORw would solve your problem if you cant get the vent prob figured out. Hope you get it figured out b4 the mold creeps up on you.

@ Mechanical--- Its a sunhut 4x4...so in reality its 56inx56inx84in. We have a 6 in venting out of the hood and an 8 inch that we are going to add coming out of another port hole.

Explain your current vent system as in filter> enclosed light>outta tent. You said you have a 6''air cooled hood and you are GETTING an 8'' exhaust fan? That seemes like over kill for a 112 cubic foot tent. A 6'' centrifigual or can fan(not a duct booster) shouldnt have a problem replacing the air in a 4x4 with a carbon filter pretty fast. Are your intake holes equal to twice your exhaust? If you are using c02 you dont really want to blow it out too fast or your kinda wasting it. No expert on c02 though. Just read you are supposed to turn your vent system off or down while supplementing c02 to get the true benefit.

I had humidity problems so i bought a dehumidifier. Turned it to 40% automatic and now the only issue is that i have to dump the water everyday. Bought off craigslist it was 140 new in box the best investment yet it it also made the pm dissapear. Hope this helps

it goes air in thru duct connected to hood>air thru hood>6 in fan pulling air out thru ducting. the 8in fan would be seperate from the filter and the hood.

we never had this problem til we closed the tent, added CO2 and took away the small fan that we had blowing in from the outside. That is why we were thinking of adding the 8 inch...its the only fan we have left.

we think that the plants are sweating...so any ideas on what makes this happen or how to make it stop?

70% is still within the ideal humidity range for plants. Most people shoot for 50% but in reality this is far to low. Ideal is 65-80%. Below 55% and you start to choke the plant, it has a hard time ingesting CO2 from the air. Same thing happens above 80% Keep an eye on it and if you see powdery mildew or bud rot you will have to lower the humidity. But there is no reason to panic for now. I run my room 65-75% start to finish, no problems.

heres some literature to back up my wild and unverified claims: http://urbangardenmagazine.com/2010/07/plantworks-part-1-humidity-and-vapor-pressure-deficit/

@ Coals, sometimes the humidity gets so high that the thermometer won't read it, it just says HI. I am more concerned about the condensation that accumulates on the walls of the tent when its sealed

Ya i was thinking you had it closed off with c02 but where is the carbon filter then? Anyways if you wanted to lower the humidity and keep it sealed you would have to go the dehumidifier route. I would just say to put the 8in in there with some passive intakes and try the c02 route next time or whenever you can get a dehumidifier. Condensation and electricity is no bueno. Good luck to you.

Also im sure there are some strains out there that can handle high humidity. Ive just always heard that 70% is the danger zone for bud mold and i wouldnt want to risk it.

its a sealed tent with the carbon filter is being used as a scrubber and the heat is vented out of the tent seperate from the air in the tent.

so we just started adding co2 to the sealed environment and the humidity went thru the roof, is that supposed to happen?

Mechanical said:

Ya i was thinking you had it closed off with c02 but where is the carbon filter then? Anyways if you wanted to lower the humidity and keep it sealed you would have to go the dehumidifier route. I would just say to put the 8in in there with some passive intakes and try the c02 route next time or whenever you can get a dehumidifier. Condensation and electricity is no bueno. Good luck to you.

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Ya most closed off c02 grows ive read about have enviormental controllers for that exast reason. I also havent read much about closed off 4x4 tents with c02. Usually they are bigger rooms and are commercial. Im no expert though.

bottom line is get more air movement and a dehumidifier

you need a dual hose AC if you want to keep your co2 in there. an AC will act as a dehumidifier