Sealed room...Humidity to low any ideas?

Hi all,

Let me describe the setup as best I can...

Its a 5m x 4m x 2.4m well sealed room

Inside the room are 2 x 3m x 2m x 2m tents and an area thats being used as a lung room (area is around 4m x 1.5m plus the gaps above the tents)

Inside the lung room is 2 x split air conditioning units, big dehumidifer up to 150 sq metres http://www.amazon.co.uk/HR-50-Humidifier-Hygrostat-hotbox-international/dp/B004PGRSXW and 2 x co2 regulators (one injecting into the intakes of each tent)

Inside tent one there is 4 x 600W horizontal lights and 2 x 1kw verts ready to switch on during flower

Inside tent two there is 6 x 600W horizontal lights and 2 x 1kw verts ready to switch on during flower

In tent one for the extraction there is a 12" phat carbon filter with 12" air force inline fan and for intake there is a 1500 rated 10" box fan.

In tent two for the extraction there is a 12" phat carbon filter with 10" 3200 rated box fan and for intake there is a 1500 rated 10" box fan.

In each tent there is 3 x 15 inch oscillating fans moving the air around nicely

Both the tents pull the air in and extract back to the lung room

We turned on tent two earlier (6 x horizontal 600s) with one air conditioner running as the other one needs regassing...and left tent one off to see how the temp and humidity would go....the fan controllers are holding the temp nicely at around 25 degrees celcius but after 6 hours the humidity has not gone up at all from around 25%...this is with the big humidifier spraying a mist inside the lung room with its stat set at 70% and the intake fan pulling the mist into the tent (its sort of pointed at the intake opening/duct)

Its either going to take about a day for the humidity to raise as it needs to fill the entire space, the lights are removing the moisture pretty much instantly or...where the intake fan is pulling in the moist air its almost instantly being pulled through the big out fan and the carbon filter is taking the moisture out before throwing dry air back into the lung room ? (if this was the case im asuming the water would stay in the filter as it cant vanish)

Any ideas?

your filters are in the tents or lung room ?? i know once you get it loaded up with plants it will rise some. also if your using coco or soil that will help raise it to. i wouldent panic yet and see what you have when its full

I wouldnt sweat it..

As soon as those plants start growing they'll be transpiring and creating their own humidity... before too long you'll be looking for ways to decrease the humidity (especially important during lights off cycle).

I normally only have low humidity the 1st week or 2.. then it climbs.. Perhaps just foliar them a bit during veg to keep RH up until they are larger and creating their own.

joesy whales said:

your filters are in the tents or lung room ?? i know once you get it loaded up with plants it will rise some. also if your using coco or soil that will help raise it to. i wouldent panic yet and see what you have when its full

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The filters are in the tents....blowing back into the lung room

One of the tents has a 4 x 50 litre tub undercurrent system in it and the other tent has a 20 bucket RDWC in it....

The humidifer is a beast...a continuous spray with a mains water source attached to it. Could the filters in the tents be taking the moisture out somehow?...either that or the lights are burning it out faster than it can go in?

I really like this humidifier: Essick Air ED11 800 humidifier Controls humidity digitally in 5% increments. It says for 2,300 sq ft but I've used it in a 250 sq ft room. I set it to about 40-55%, it does seem to cycle a bit much if set too low but even acts as an evap cooler as well. I keep it topped off w/RO water. It seems they over exaggerate the square footage on these things, and I've done a lot of footwork looking for the right one among dozens of types, makes and models.

the ac will usually keep the room on the dry side until lights out where the plants really raise the humidity. i set the dehuey to 50% and let the ac run 24/7. lights on i am at 40%. lights off the dehuey kicks in and keeps it at 50%. the rh will rise once those tents are full of plants.

If things seem dry my floors are covered with pond liners that run up the walls, I just water the floor, evaporation does the rest. Be careful with your humidity levels as your buds get thick, mold will fuggin ruin your day.

Phillthy said:

the ac will usually keep the room on the dry side until lights out where the plants really raise the humidity. i set the dehuey to 50% and let the ac run 24/7. lights on i am at 40%. lights off the dehuey kicks in and keeps it at 50%. the rh will rise once those tents are full of plants.

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We dont have a dehumidifier just a humidifier (I think im getting this the right way round)

during veg the lights are going to be on 24/7

So as it is with the lights on at 25% (holding at 25% with no plants in) and it will raise a little bit when the plants are in but not much when they will be small and in veg is this ok? i.e if its to high a % then its a problem and if its a low % its not so much of a big deal?

What im trying to say is is it safe to put them in at 25% humidity?

yeah man. i ran my room for a year at 30% and run it at 40% now. i see no ill effect at all. I have a buddy that cant get his room above 25% and his stuff turns out dank.

They say higher humidity is ideal but you can still veg with low humidity, I live in the desert and it is dry most of the yr. here, the plants grow just fine.

If your humidity is on the low side, keep your room a bit cooler(71-72f). Hot and dry really slows your growth. I too live in the desert and they will be fine at 25%, but at 50 they will grow faster and be healthier. Also at 25% dont give them too much wind(dont point fans at them).

72f lights on temp? No. That's like night temp. You have a small room. Raising humidity shouldn't be hard. Make a wick. Get a 5 gal bucket, fill it with water, and put it in the corner of your room with a supershamy or a shamwow or w/e the fk they're called stuck in it and staple it to wall. If you can't find a shammy use a cotton towel the shammy's are more absorbent so they will wick up higher. Make sure the water doesn't drip from the wick onto the wall and onto the floor, might need a block in between so it drips back into the bucket. Have a bit of airflow on the wick. Should raise your RH pretty quick. If it's not enough add another one. Or get a real humidifier ;-)

Keep temp at least 80f if your unfamiliar with strain. Keep RH high in early veg and lower gradually to 45-50% as you get close to kick.

Your ACs are removing the water from the air. Cold air can't hold as much water as warm air can, as the warmer air runs over the cold air conditioning coil some of the moisture condenses out of the air.

Using a wick works well in a small area, but doesn't do much if you've got any serious extraction or air conditioning.

A humidifier works ok, but if not all the "mist" put into the air evaporates quickly you can end up with mould or mildew problems with your room or plants.

The best option is to use an "evaporative cooler" or "swamp cooler". Same thing. This is basically like a wick system on steroids. Water is pumped over a absorbent pad at the same time air sucked through the pad. This evaporates the water completely into the air with no mist. In a warm and dry area an evaporative cooler will raise the humidity quickly, as well as cool the room, which indirectly also raises humidity because the extra cooling will cause your extraction / AC to run less.

I just ordered the parts to build 4 evaporative coolers from 5 gallon buckets. With the cooler air holding less moisture now being drawn into my room from outside I was down to as low as 16%RH. No good at all.

Shafto said:

Your ACs are removing the water from the air. Cold air can't hold as much water as warm air can, as the warmer air runs over the cold air conditioning coil some of the moisture condenses out of the air.

Using a wick works well in a small area, but doesn't do much if you've got any serious extraction or air conditioning.

A humidifier works ok, but if not all the "mist" put into the air evaporates quickly you can end up with mould or mildew problems with your room or plants.

The best option is to use an "evaporative cooler" or "swamp cooler". Same thing. This is basically like a wick system on steroids. Water is pumped over a absorbent pad at the same time air sucked through the pad. This evaporates the water completely into the air with no mist. In a warm and dry area an evaporative cooler will raise the humidity quickly, as well as cool the room, which indirectly also raises humidity because the extra cooling will cause your extraction / AC to run less.

I just ordered the parts to build 4 evaporative coolers from 5 gallon buckets. With the cooler air holding less moisture now being drawn into my room from outside I was down to as low as 16%RH. No good at all.

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Link to this kit? I'm @ 25% full of plants & w/out a/c (which I need). The heat & dryness are giving me k problems. I've been browsing and contemplating shelling out for a portable that I can duct into 3+ tents.