2 400w hps in a 3 1/2 sq ft room +rep

T

T.H.Cammo

Well-Known Member
Okay, I got two things to say:

1. One 400 watt light would be overkill for that space.
2. 3'x 1 1/2' = 4 1/2 sq. ft., not 3 1/2 sq. ft.
 
nellyatcha

nellyatcha

Well-Known Member
crazeehaze said:
have a look at my journal, im using 2 x 400watt hps, my room is pretty big and i still struggle with heat beeing up in 31c sometimes.. i gave theese girls 4 weeks veg and quite alot of lst. still..now 1 week into flower they are growing into a god damn forest in here..

unless you have cooltubes and one hell of a fan i cant see you pulling this small room out tbh..
Click to expand...

yeah i know i decided to go with 1 but look at her reaching for the light and its 6in away 2 in growth last nite
 
nellyatcha

nellyatcha

Well-Known Member
T.H.Cammo said:
Okay, I got two things to say:

1. One 400 watt light would be overkill for that space.
2. 3'x 1 1/2' = 4 1/2 sq. ft., not 3 1/2 sq. ft.
Click to expand...
guy incognito said:
you dont calculate it that way either. 3L X 1.5W = 4.5 sq ft

3 X 1.5 X 4 = 18 cubic ft
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estimation i went up to a half ft its less then that. its like 15" but in all reality its droped down to 3sqft. and i keep temps to 77 degrees with 1 400w hps 6 in from the top in that area.
 
vic?

vic?

Active Member
Yes nellyatcha is correct ?x?= squared but ?x?x?= cubed and cubed as you know is the formula we use for calculating our ventilation.
 
pitbull1117

pitbull1117

Well-Known Member
I need some serious help. ok my sorry to post in here but it is spur of the moment. my grow box is 26"x19"x36". i dont know how many square feet that is but im having a heat issue with my 250w hps in this area. i have 2 106cfm muffin fans 1 intake and 1 outtake. my temp is now reading 94 degrees. but it doesnt feel that hot in there and i stuck my hand over the top of the plant and it doesnt feel all that hot. should i worry? or should i say screw the exhaust and have 2 intakes? i just don't know what to do. they are both on the outside of the box. should i move my outtake to the inside of the box and leave the intake on the outside?
 
pitbull1117

pitbull1117

Well-Known Member
i really dont know what you mean im using a mercury thermometer. are you saying dont keep it under the light basically?
 
nellyatcha

nellyatcha

Well-Known Member
pitbull1117 said:
I need some serious help. ok my sorry to post in here but it is spur of the moment. my grow box is 26"x19"x36". i dont know how many square feet that is but im having a heat issue with my 250w hps in this area. i have 2 106cfm muffin fans 1 intake and 1 outtake. my temp is now reading 94 degrees. but it doesnt feel that hot in there and i stuck my hand over the top of the plant and it doesnt feel all that hot. should i worry? or should i say screw the exhaust and have 2 intakes? i just don't know what to do. they are both on the outside of the box. should i move my outtake to the inside of the box and leave the intake on the outside?
Click to expand...

yes outtake inside intake outside or both inside. and exactly where are you reading the temps? because i have mine by the light and it says 88-90 and im using 400w hps in a 3x1.5 room with only and osc.fan
 
wonderblunder

wonderblunder

Well-Known Member
pitbull1117 said:
I need some serious help. ok my sorry to post in here but it is spur of the moment. my grow box is 26"x19"x36". i dont know how many square feet that is but im having a heat issue with my 250w hps in this area. i have 2 106cfm muffin fans 1 intake and 1 outtake. my temp is now reading 94 degrees. but it doesnt feel that hot in there and i stuck my hand over the top of the plant and it doesnt feel all that hot. should i worry? or should i say screw the exhaust and have 2 intakes? i just don't know what to do. they are both on the outside of the box. should i move my outtake to the inside of the box and leave the intake on the outside?
Click to expand...
Experiment, try something check the temp.... If anything I would do a passive intake and 2 exhausts...... What are your ambient temps outside the box....
 
M

mikehod

Well-Known Member
mini cabs are hard to light with hps's without heat issues is your ballast remote on in the box?i got a 12.5"x20"x29"h(thats 1.7'sq. and bout 4 cubic for the math challenged)inside it the is a 150 hps and 3 26w cfls and the cfl's are hotter than the 150 bet i could put 2 150's in there and stay cooler just got the cfl's for the 6500k in early flower the trick is the ballast is inside one of the exhaust light traps cabinet is cooled with a 12V 1.5w charger from radio shack $15 5 92mm pc fans 2 exhaust 2 supply's one blowing on hps bulb to reduce heat build up. always intake low and exhaust high.lol high im high so this might not make sense i can explain it better i ya want but got ona those $9 remote digital thermo's form walmart and it always stays bout 2F different inside and out also got a bout 12x12 speaker with a 70hps and 15w led the 70w hps ran remote put out no heat
 
nellyatcha

nellyatcha

Well-Known Member
wonderblunder said:
PC Fans= no good except for the smallest of boxes.... Hard to make them light tight......
Click to expand...
nice info man i neve done that i always had a big room that i broke down with mylar and e-blankets. has anyone seen indoor purple widow grows start-fin with pic or even sour kush.?
 
J

Jtoth3ustin

Well-Known Member
a 400W HPS will cover 3'x3' fine. i wouldnt run one MH and one HPS though. ive had the problem of the two seperate lights instead of being mixed stressing the plants. i started using a 1k HPS with 400W MH around it. more proportioned.they receive constant HPS so to never have to rotate the plants.
 
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