Indoor hydro grow on high humidity region...

[348montesa]

Hi everyone, I am planning a hydro grow in a place where the average relative humidity is around 67 to 72 %. The 2 rooms i am planning are around 3m x 3m (9x9ft), with 4 or 5 k lights each. Av temp ouside in the shade is around 25 deg C (77f). Height of the room is 2.4m (7.9ft)

I was planning to have 2000 cfm (3500m3h) fans in each room to control temp and humidity, circulating large quantities of air.

Now i am wondering if the ambient rh is simpliy not too high fot this method. So i have a few questions:

If a get sufficient air circulating can i conrol rh and temp adecuately?
Would a dehumidifier help if air pumped in in such large rates?
Would i be better ofth ac on this situation (i would prefer to avoid this and would only go this route if really necesary).

Will be growing in rockwool, flooding every 3 days.

Thanks advance for your suggestions.

 

[Papa]

i had a room that size, and just for fun between runs i turned the lights on without the a/c to see what would happen should the a/c ever go out without a temp shut-off switch. i shut down the experiment when the temps hit 130 degrees . . . . and it didn't take long to get there.

i would suggest that if you're not experienced with that environment, that you start smaller than 4 or 5k. i would expect that with 4 or 5k you'd have to move an incredible amount of air to keep it within limits . . . and a dehuey is only going to add to the heat you're making without making a dent in the rh because your turnover would be so great.

 

[mayonnaise]

IMO you would have to move a lot of air to keep 5k cool in that small a room. How high are the ceilings? If they are like 12 feet you might have a chance if you can pull all that hot air from the ceiling. I'm with papa on this one ,start with 2k and grow as your room allows. Or at least be ready with an ac just in case. If you aren't gonna run your fans during lights out you might wanna think about a dehuey.

 

[348montesa]

Thanks for your replies. With a 3500 m3h fan i would recycle the whole air 2.7 times a minute. Do you think it is still problematic? I will start the grow with fewer lamps, because my mothers still dont give me enough clones for the first round. I just would not like to invest first in expensive fans to then have to buy an ac when i moove further to 4 k ( i think i wont be getting really over 4k, it will be 10x 400w). And I would really like to avoid a/c's...
Thanks again!

 

[Papa]

you haven't mentioned your hoods . . . but you've got to start there.

and moving that much air, forget about controlling humidity . . . . you're going to get the rh you get, you won't be able to control it.

running rooms without a/c isn't my area of expertise . . . . but i'm sure that someone here that runs something close will speak up . . . . . guys? girls?

 

[348montesa]

Thanks Papa! Sure, I forgot to write about the hoods. Non cooled Megalux V.
I was afraid of what you said: with that amount of air movement I won't be able to "control" Rh. Maybe just playing a little with vent speeds, but that only a little, because of temp restrictions.

Now, given there is water evaporating from the rockwool and 10 400W lamps, if I the outside Rh is around 68%, what Rh should I expect? Still higher or lower that the 68% outside, or just about the same.

Taking out 2.7 times the space's volume of air in a minute (at the end it will be less given the ducting induced losses) is a lot. The intake will be placed just a bit higher than the lamps and made in such a way that the intake will be distributed (using an inverted "T" duct shape, open on both ends and perforated on the lower duct with some small holes). Fresh air in will be exhausted at a about plants level. I know this works from a temp. perspective.

 

[Papa]

given there is water evaporating from the rockwool and 10 400W lamps, if I the outside Rh is around 68%, what Rh should I expect?

if you're turning over the air volume every 20 seconds, you could have a jacuzzi in that room and you're not going to impact the rh.