Trying to lower humidity to stop mold, what should i do?

My humidity levels with the lights on are around 30-40%, which i have read is acceptable, but my humidity with the lights off is 55 to high 60's, which i have read is not acceptable, there is beginning to be some powdery mold on some of the leaves.

Now i have a good dehumidifier, it is a LG one and cost $250+ tax at home depot. Even with it running while the lights are off the humidity is till high,BUT i also have the intake fan running 24/7 sucking air from outside and pumping it into the grow room. Should i turn off my intake fan while the lights are off? Also should i turn off my exhaust fan with the lights off aswell? the temps dont get very hot with the light off, max will be around 75 degrees.

So what should i do?

I am also about to run a sulfur burner during the dark cycle, my plants are 4 weeks in flower, is this alright?

for sure id stop the outside air intake during darkness. there are days and nites the humidity level outside is 60-100 percent. i use a small space heater during nitetime to help keep the air dry and warm. air circulation is very important, my advice would to bring in air from indoors thru your room and vent out the old air outside. as far as the mildew its a tough battle, what you see now is weeks into its damage, a good remidy isto mix baking soda and water and spray the lower parts of your plants, this changes the PH on the leafs surface stopping the spread of powdery mildew. good luck

I agree with walli. I cant understand why ur dehumidifier is keeping it low. Is it full every morning when u check it? If so, id unscrew the plug and run a hose into a drain so it can keep up. Might also be a prob in the roots.

hmm what if i ran my co2 generator while the lights are off?

Plants use Co2 during lights on from what i hear. Might wanna research that. Ur levels should be fine. I keep mine 45% I have no probs.

I still dont understand why ur dehumidifier doesnt work at night? Is it on a timer? Let it run.

runs 24/7 but for some reason the humidity is much higher at night, I turned off the intake fan and got the night humidity down to 55 tomorrow I'm going to run no exhaust fan aswell and see what happens

stop the air intake when the lights are off and make sure your dehumidifier has 12 inches of air space around it. how many pints is your dehumidifier?

purple voodoo#5 said:

stop the air intake when the lights are off and make sure your dehumidifier has 12 inches of air space around it. how many pints is your dehumidifier?

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I am 4 weeks into flower and my humidity is around 50 to 60 percent
Is this going to be a problem ?
they look fantastic (purple kush)
this is my first indoor grow
should I get something for the humidity
or are these levels ok ?

i have a hose from my dehumidifier going into a 5 gal bucket so it doesnt fill up the reservoir. This is the dehumidifier i have right there

http://www.google.com/products/catalog?q=lg+dehumidifier&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a&um=1&ie=UTF-8&cid=6054809576780684183&ei=bjE1S6jKJoz2sgOa0_2JBA&sa=X&oi=product_catalog_result&ct=result&resnum=1&ved=0CBYQ8wIwAA#ps-sellers

If there are no lights on theres no sense to have the fan on. Set it on a timer for 5 minutes before lights on and 30 minutes after lights out.
Block any nitetime air from getting in. Use a fan to move air around.

What is the setting on? Mines set at 50% and i'll get 5 gall in 12 hrs.

what should i do? run another dehumidifier?

Dude all you need is a thermostat thats kicks the intake on and off and you will have the idea set up.I was raized on a farm we had these in the barn controlling a big deisel furnace.If you have trouble finding one.Check a farm store.I hope to have my room like this soon.

I'm having the same issue. I bought an eva dry mini-dehumidifier but it didn't do anything. my levels are like 70-80% humidity and I am shitting my pants. I just ordered a larger 25 pint dehumidifier and am praying it will keep up. My room is only 5x5x7. How big is yours?

Seaweed11 said:

I'm having the same issue. I bought an eva dry mini-dehumidifier but it didn't do anything. my levels are like 70-80% humidity and I am shitting my pants. I just ordered a larger 25 pint dehumidifier and am praying it will keep up. My room is only 5x5x7. How big is yours?

Click to expand...

MY TENT IS 4X8 with 2 600watt hps.
I am 4 weeks into flower and my humidity is around 50 to 60 percent
Is this going to be a problem ?
they look fantastic (purple kush)
this is my first indoor grow
should I get something for the humidity
or are these levels ok ?
any info would be great.

i fought with the humidity issue and after a few years of messing with it i found that a $10 fan blowing on my girls was all i needed. KISS keep it simple stoner

Just got my dehumidifier, it works amazing. http://www.google.com/products/catalog?source=ig&hl=en&rlz=&q=soleus+dehumidifier&um=1&ie=UTF-8&cid=12352532472279069244&ei=VHo7S7vJBozIsAPs_73DBA&sa=X&oi=product_catalog_result&ct=result&resnum=1&ved=0CBQQ8wIwAA#ps-sellers
Lowered my humidity from 80% to 35%. Very nice.