Humidity too high.....

[yota]

So my humidity is around 70% week 4 of flowering and i have been fighting off some powdery mildew. How can i get the humidity to go down? I bought a good inline fan and though that it would help, but it actually made the humidity go up i think. So should i lower the speed of the intake fan and try to get the temp to rise to 80? (currently 75ish). Add more circulating fans? Any tips?

[WantDaChronic]

get as much air sucked out of that room as possible, the more the better imo and it will greatly reduce the mildew and mould that will undoubtably appear soon enough unless you lower your humidity if that isnt an option, look into buying a dehumidifyer or even some damp-rid like product which will also suck the moisture out of the air

[Tom]

get as much air sucked out of that room as possible,

Yeah, add another exhaust fan and make sure your intake fan is not bringing moist air into the grow room.

 

[Al B. Fuct]

I run a dehumidifier in my flowering area 24/7. During lights-off, the ambient air available at this cold time of year to draw into the grow is at about 10-12C @ 70-85% RH. The op airmass would similarly rise to 70-85% without it.

 

The dehumidifier also adds a small amount of heat to the room while sucking water out of the air, maintaining lights-off temps at about 20-21C. If I had to rely on pumping ambient air at this time of year through the room to drop humidity, it wouldn't drop far and temps would be far too cold during lights-off.

 

In warmer months, where avg ambient temps run above 20-22C, the dehumidifier isn't needed as much. Moving lots of air through the op will usually do the trick to get RH below 50%.

 

Now, if your op can draw heated air from a living space (mine can not), lucky you! That's usually enough to drop the RH during cool months. Air at ~10C @ ~80% will drop to 30-40% if warmed to around 20-22C. All you need then is an efficient exhaust ventilation system to control RH.

[yota]

So i was thinking of turning the inline fan down to increase the heat therefore lowering humidity.....is this a bad idea? Should i keep as much air flowing as possible? And does damprid really work? Thanks again guys

[Tom]

Humidity is is mostly due to poor ventilation, if you are using HID lighting the grow room should be warm enough just from that, how about giving us a description of your grow set-up?

 

[Al B. Fuct]

I'm with Tom, some more detail on what you have built up would be useful.

 

If your intake air is cool and humid compared to what you need, slowing the flow through the room would bump the temps up a bit, dropping the RH as you would expect. It would be an OK temporary solution provided there's enough through-flow to provide enough CO2 for the plants- and of course, adequate oscillating circ fans moving air around inside the op. Circ fans will help reduce powdery mildew.

 

The old milk and water spray (10:1, water:milk) works to get rid of the PM you have. 30g full-cream milk powder in 1 litre of water is said to be more effective than regular full cream milk.

[Shithappens]

Several things can help you out

 

What is the humidity of the air you are sucking in if that is 60% you wont get it below that without Al B. Fuct's suggestion of a dehumidifier (consider getting your air from elsewhere) If you are in a cupboard do not exhaust anywhere that the exhaust can be sucked back into the grow or you will create a feedback loop that will get wetter and wetter

 

Also Isolate all your water from your growth area .... if your in pots cover the pot tops as a fair bit of water evaporates from there. Move any watering cans tanks etc from your grow room it wont help much but it will a bit a tank with a heater in it will raise your humidity surprisingly

 

Ozone is supposed to be great for mold ive used a TV as a generator and it worked great but this i wouldnt recomend

[Al B. Fuct]

And does damprid really work?

 

Depends on what you mean 'work.' It's OK in a poorly ventilated closet to keep mould off your leather jacket, but you'd need an awful lot of the stuff to keep up with a grow op.

[Tom]

30g full-cream milk powder in 1 litre of water is said to be more effective than regular full cream milk.

Yeah, that's due to the way that "fresh" milk is processed, a lot of the good bacteria gets kill off too.