TOO HOT! Emergency grow box build - comments welcome

[dbfr3sh]

My grow is suffering and i may just trash my current project and start over. My ambient temps are 75* with the ac on, and outside my temps are 85-90* usually. My growroom is in a big closet about 3 x 6 x 8 and my temps even with 3 fans and an aircooled light (400w) are 86-90*. Obviously this isnt going to work so i have drawn up to idea for a box to build but i dont know which would work better for me. Cab 1 seems better but i would have to run 4 fans + the light and cab 2 is only 3 fans + the light but i know i could move more air w/ the scrubber exhuasting by itself. The frame will be constructed from 2 x 4's and it will be 3.5 x 3.5 x 5. The outer shell will be black/white 6mil poly. i dont know how to cut out the holes for the ports yet im thinking drawing the circle out and cutting an X in the middle and feed ducting out.

Any suggestions are welcome i have about a week to build it so anything i need to know before hand should help. thanks.

*picture were drawn up quick. im not a pro as designing*

 

[purpledomgoddes]

run temps up to 100+ w/ no problem.

w/ that type of cab, can easily acquire a 5k btu ac for one-hundred coins (new), or ~ fifty coins (used/off net). will cool room down to whatever temps desired.

when running higher temps, maintain higher night temps.

run night temps from 78-88*f. the plants will acclimate/adjust/adapt. those that dont are culled. this rarely occurs. plants in nature deal w/ adverse conditions all the time; from high deserts of dry heat, to low valleys of wet heat.

also, trick to making plant think it has had long cold nigh is to lower temps to as low as can get ~ 1hr before lights on/1hr after lights on.
this registers as negative diff, or night temps being cooler than day temps, even though they were actually the same or higher. timing is key.

higher temps are not in themselves bad; just add more air flow in the room. the circulation is the key. it permits transpiration; i.e., the plant will evaporate more water vapor as the temp climb. provide a mechanism to de-humidify and have the 'highway', or 'path' for the water to be carried in/on: air.

if lights on temps are 90*f, keep night temps @ 78-80*f. may be surprised in the morning, after doing this, how much have grown.

plants respire all the time - dont stop when lights go out... higher temps=higher metabolism (growth/fruiting).

hope this helps.

 

[Philosophelon]

I don't really want to start an argument here, but for my , 100+ temps will seriously impact the quality of your buds. Also, while it is true that a plant's metabolism speeds up and it will grow faster in higher temps, atmospheric CO2 concentrations will still limit the rate at which photosynthesis is conducted, so that trick only works if you have supplemental CO2.

As far as your potential setups, I don't think the first will work, because you are pulling outside air through your hood and then exhausting it, without exhausting any stale room air. The second one looks like it will work though.

To increase cooling and airflow, I would recommend that instead of using one of your fans on the intake, install a passive intake, and run separate A/C reflector and exhaust HVAC circuits. An intake fan is only necessary if you are moving a lot of air, and you don't need to move very much air to cool 400w.

Like this --

Exhaust Circuit: Carbon Filter > Fan > Exhaust

A/C Reflector Circuit: Outside Air (Intake) > A/C Reflector > Fan > Exhaust

 

[dbfr3sh]

yea dont worry about that im taking lowering temps. im running mostly indicas and from what i know they dont like high temps.

Philoso: im not running an ac in there its too expensive for me right now. where i live its really hot now so i run my central air all the time. also my carbon filter has a fan so i would have to run it like cab number 2. also in cab number 1 the goal is to cool the light down by taking outside air- passing it thru the light and then exhuast it out. Im hoping that the light temps go down enuff to lower my cab temps. and since im already exhuasting the light anyways i figured id hook up the carbon scrubber to the light and kill two birds with one stone.

What is a passive intake...prolly should know this....is it just a hole in your cab that air is drawn in from all the negitive pressure?

also does anyone know if i hook up my cab like #2 and not plug in the fan thats connected to it will the suction from the cage fan burn out the motor on the fan?


anyone with experience in this want to chime in...

 

[FreezerBoy]

Cab 1 is a death trap, an easy bake oven. It will kill anything you put in it. Air exchange is a must and it has none.

Cab 2 is less dangerous but, unless you know your stuff, intake fans should be avoided as they are the fastest way to achieve positive pressure. Positive pressure means no odor control and advertising to all your neighbors. Passive intakes are intakes with no fans. Punch 3 equal sized holes, one at the top for the exhaust fan and two at the bottom for intake (some go as far as 4 intakes). This gives you negative pressure. No air escapes other than through the scrubber. Intakes should be filtered both for pests and dust.

 

[Philosophelon]

What is a passive intake...prolly should know this....is it just a hole in your cab that air is drawn in from all the negitive pressure?

Yeah, but you have to light-proof it if it's in a flowering room (or if necessary for stealth reasons). You can do that by building a box with baffles inside, or by installing some ducting with bends, and spray painting the ducting flat black inside.

also does anyone know if i hook up my cab like #2 and not plug in the fan thats connected to it will the suction from the cage fan burn out the motor on the fan?

I'm not sure what you are asking.

 

[guest 77721]

I would cool the light with an unrestricted fan pulling air through the cooltube. This takes the maximum heat out of the box. Use the other fan for the scrubber to ventilate the growbox with a passive intake. That will give you the most optimized ventilation system.

 

[dbfr3sh]

freezerboy: the carbon scrubber in cab 1 has a 150cfm fan built into it. thats what would be exhuasting. the cage fan on the right would be sucking air from the outside of the box (inlet->light->oulet from cage fan.) this i figure would cool the light better than sucking thru the cab temps thru a scrubber and then out the cage fan. i would be sucking up ambient temps and then passing thru the light and back outside with none of it exposed to the cab enviorment.

i didnt know you could get away with no fan in the inlet. that works better for me.

Philoso: i ment to say i have a connected fan to my scrubber and my cage fan would be sucking air thru the scrubber to outside the cab. now if i let that fan run 150cfm but my cage fan is pulling 300cfm will either running or not running the fan scrubber burn out the motor becuase the cage fan is pulling more air.

still smoking my snow whites, cant think for shit. hopefully someone gets what im saying thanks.

 

[FreezerBoy]

freezerboythe carbon scrubber in cab 1 has a 150cfm fan built into it. thats what would be exhuasting.

D'oh! Missed that . Carry on.

 

[TheCheeseMan]

my temps even with 3 fans and an aircooled light (400w) are 86-90*.

if you can, exchange the light for a 250w or a 175w, you can still get a nice yield with much less heat. btw, look like it'll be a nice setup

good luck

 

[stke_fingas]

i agree:
OUTSIDE>HOOD>FAN>OUTSIDE
FILTER/FAN>OUTSIDE

i'm no expert but i run a 400W in less than 5 cubic feet with CO2 and no exhaust. that light is easy to cool. my tips are about 4-5 inches from the bulb. stanley blower modd on 6" duct and cool tube. temps are about 5 degrees above ambient with my room fan off for co2 injection. never tried more then about an hour with the exhaust off cause of humidity, it rained in my cab last year lol. i do 30 min periods with the fan off now. your cage fan is 300cfm and the stanley is somethin like 200cfm(guess). i can touch the glass inches from the bulb and its just warm, not hot. the plants love it, i got proof!

 

[Maj.PotHead]

OUTSIDE>HOOD>FAN>OUTSIDE upto attick
FILTER/FAN>OUTSIDE upto attick

if you exhaust in erea that supplies your fresh air you'll have problems with temps

i'm currently running and have been since late last fall a spot in the corner of my closet
inside dems are 28 inch deep 48 inch wide 73 tall. before this current setup i ran the whole closet 7ft x 5ft floor @25w per sqft now i'm approx 80w per sqft
crammed in there is a 400w hps in cooltube 6inch from wall and 400w mh in aircooled hood not even 6inch from the tube. my temps run around 85 deg lights on and whatever my house is 73-74 deg lights off. my modded stanely fan pullls through a 4in carbon scrubber 4inch ducting to a 4 inch Y adaptor. then 4 inch ducting off from Y to the hood and cool tube pulling air over the bulb exhausting the heat they create directly to another Y and upto the stanely out upto the attick. i'm lazy and am running forced air intake 95cfm blower fan both ballasts are on top shelf of the closet. now if a change and get 6in ducting 6in adaptors change forced intake to passive my temps will drop to w/in few degrees of whatever house is. but that takes few bucks i dont have currently

heck i forgot the best part 2 sides black n white poly white facen in 1 side of front is secure the other side is a makeshift door. poly wraped around the corner and scured with velcro. the top is partial plywood and rest poly lol Old Soul seen it Sirsmokealot has alot also and will admit looks and works nice

before this house in the last i had a C25 style wardrobe cab i modified ran my 400w hps in air cooled hood. i ran my setup just as Red Greenery suggested stright run outside of cab fresh air for the hood and bulb being exhausted by the modded stanely blower fan into attick. my 95cfm fan was on the 4inch carbon scrubber inside the cab above the hood to exhaust the scrubbed air and any heat in the cab. my temps there ran 3-7 deg of what house was in the sumemr where i live it get above 115 alot from mid july through aug normally. that house my thermostat was set @77 cab temps 82-83 this house thermo set @73 flower chamber temps 83-85. not bad i have 2sqft floor more then the cab had and i have another 400w light.

for some very good ideas on 400w lights in cab and or small spaces

http://www.icmag.com/ic/showthread.php?t=21967&highlight=400+watt+club
over 300,000 views and 1,600 replys

for ideas on how my cab was setup just click the
past grow grow sugar shack 06 link in my sig

 

[stke_fingas]

venting to the attic is the best option, but not everyone can do that. i don't, wish i could though.

 

[dbfr3sh]

yea cant vent into an attic just a room w/ central air. so it seems like im going to go with cab number 2 with passive intakes. im going to try to remove the fan attached to the scrubber so it doesnt burn out from sucking force of the cage fan. i just built my box and i ordered some black and white poly 6mil and a zipper and will post pictures when all is done hopefully by the weekend-early next week.

thanks for replies.

 

[stke_fingas]

your cage fan that is going to be pulling through the filter may be too much air flow. carbon filters are rated for a max flow and the fan attached to it may be the perfect match, anything more and security compromises are made. if you smell it EVERYONE will smell it.

 

[Philosophelon]

Philoso: i ment to say i have a connected fan to my scrubber and my cage fan would be sucking air thru the scrubber to outside the cab. now if i let that fan run 150cfm but my cage fan is pulling 300cfm will either running or not running the fan scrubber burn out the motor becuase the cage fan is pulling more air.

No it should be fine, but your 150cfm fan may not help at all if you are pulling a lot more than 150cfm past it, because it won't be able to keep up, in which case you should remove it to save electricity, and because it may add drag to your 300cfm blower.

 

[dbfr3sh]

No it should be fine, but your 150cfm fan may not help at all if you are pulling a lot more than 150cfm past it, because it won't be able to keep up, in which case you should remove it to save electricity, and because it may add drag to your 300cfm blower.

thanks! answered my question. if it ends up smelling i can always add the fan back on the scrubber.

 

[dbfr3sh]

completed

completed

i picked grow box number 2

so i completed my grow box and it looks great. cost about 50-60 dollars to build. my outside (the cab) temps are 77 with central air and my cab temps are 85. now i disconnected my fan that was attached to my scubber and took it off completely. my cage fan is now pulling thru my scubber and the light and then back outside the cab. i think my intake ports mayb too small but i didnt want to cut them too big.

i have two ports both 4in x 4in. i still have alot of neg pressure and high cab temps so i was wondering if one of you math guys wouldnt mind telling me how big my ports need to be??? the cab size is 3.5' x 3.75' x 4.5'. my light (400w hps) is 3.5' off of the ground.

thanks guys!

 

[dbfr3sh]

anyone know what size holes i need?

 

[pinecone]

This is what I would do
- take the ducting off the inflow side of your hood so that you are exhausting air higher in the cab which should be the warmer air.
- buy 2 8*8 dark room vents to use as inflow vents. This should give you enough input area to work with your fan. It will also keep your cab light proof. Your fan is not going to work nearly as well pulling a load as a good in-line.

Pine