400watts of cfl, less than 20% relative humidity, help!

covertgrow

Well-Known Member
right, so i have my small box setup which is 60/90/120 cm
i have a 300w dual spectrum cfl in there with 4 20w daylight cfls,
i have added 2 pc fans on the rear of the box, 1 at the bottom for intake and one at the top for exhaust,
if i run both fans my temps drop to 60f
so i am just running the exhaust fan with the intake passive my temps stay nice around 72/76f but no matter whether i have 1 or 2 fans on my relative humidity is always showing as low (below 20% on my digi meter)
i have placed the bottom tray of a propogator in there full of water with a grill on top which i have 2 pots on, but this still dosent get humidity above 20%

any ideas what i can do apart from buying a humidifier as i think soon as the plants are a decent size my humidity may go up,

when the lights and fans are off my humidity goes up to 60/70 rh, and temps drop to around 63/67f

by the way, at the moment i only have 2 small plants from bagseed in there as a practice run to sort out any problems with the grow space before i pay for decent seeds
 
Yah. when your growing in such a small area your fans are fully removing the air and replacing it every couple seconds. try putting a glass of water in front of your intake or the damp cloth like above. this will suck the evaporated water into the box. try it with the cloth.
 
Or pump outside air into the grow room.... If its fresh u shouldnt have any issues with humidity... any one of these methods with a tweak or 2 should sort you out!!

Cant you upload some pics?
 
hi!
thanks for replying so fast,
i have tried having the intake on and exhaust off but the box gets too hot if the hot air's not getting sucked out (89/92f)

i will have another go but try the wet cloth/glass of water by the intake fan and see if that helps with the heat aswell as humidity,
thanks again
covertgrow
 
hi!
thanks for replying so fast,
i have tried having the intake on and exhaust off but the box gets too hot if the hot air's not getting sucked out (89/92f)

i will have another go but try the wet cloth/glass of water by the intake fan and see if that helps with the heat aswell as humidity,
thanks again
covertgrow

Is the box in house/ upsairs downstairs?? is there window near by??? need some more info really..
 
if u check my small grow.. i only have intakes and am using about the same wattage as u and i dont seem to have any temp or humidity issues... My fan sucks air from a window thats nearby.. the fan is enclosed in the cuboard with a vent thats a few foot from my window... fresh air mixes with the room air before being blown into the grow area.. at the other end of the grow room there are vents on top and below where air exits..
 
thanks for your input urbanfunk i had a quick look at your grow, im very impressed, subscribed!
i will try and get some pics uploaded tonight but looking at your space i think i may have to change mine a bit!
the reason i have had the exhaust on rather than the intake is that it gets quite cold in the box with the intake on and exhaust off (59/60f) the box is on the middle floor of my house
quite near a window but i need to keep it relatively stealthy so cant really have any ducting on show, i dont have any mylar in the box yet just painted matt white so maybe that will help things a little once i get that in there,

by the way urbangrow, how do you hang your lights? my 300w cfl is bigger than an enviro (8u) and is heavier the glass end so if i suspend from the screw fitting it tilts downwards, could i tie string or something on to the end of one of the u's to hold it level, i was going to try but thought it may heat up too much in one spot or something, at the moment i have the bulb with only about 1cm gap before the reflector which is screwed to the "cieling" of my box and im moving the pots closer instead of lowering the light,

thanks again!
all your help is appreciated,
covertgrow,
 
added

ok i went to the shop today and got a roll of heat reflective silver,
ive lined the box and door and also picked up a soil moisture meter,
hers some pics so far and i will check on the humidity situation when the lights are back on tomorrow as i didnt finish lining the box till 5 minutes before lights out,

also i know my bulb hanging arrangeent is far from desireable its just i cant find anything more suitable than goold old string at the moment!
i may have to pick up a new reflector as i was using one from a cool tube and its slightly too big to fit comfortably,

thanks!
:bigjoint:covertgrow




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