Ikea Grow Cab WAY TOO HOT! Help!

So after finally finishing up the ikea cabinet by adding a door and a sliding floor, I decided to throw my two plants that I have now into there overnight. Checked them this morning and they were looking just fine (well, relatively... one of them is really being finicky regarding nute burn but that's another issue) but temps were WAY TOO HOT, ~95F or 35C. I really do not get how they are getting this hot (by the way, this is measured at soil level so who knows how hot the top canopy is getting! yikes!). Even with the door opened, temps are still too hot at ~87F. Just to let you know, this was just a test run and I know there are still some details I need to work out with the box such as light spectrum, light proofing, odor control, etc... However, this IS a legal grow so right now I'm more concerned about the "barebones" of the box and getting it to run below 80F.

Anyways, here are some specs on the box:
Lights 12x 23W for a total of 276W
Exhaust 1x 4" Inline Duct Booster Fan connected to a 4" drain grate used as a flange(I know these usually have a bad rap, but at ~60CFM it should be fine, right?)
Intake about 1ft x 3/4ft passive intake and a oscillating fan to circulate air within the cab
Dimensions 2ft x 2ft x 2 1/2ft tall for a total volume of 10 cubic feet

Overnight trial for the new cab


12CFL fixture I made (just threw whatever bulbs I had in there for now)


Passive Intake still needs to be light proofed/filtered (any tips?)


Exhaust system






With the 60CFM booster fan, I am roughly getting 6 air changes per minute which SHOULD be fine. I'm totally fine with just upgrading to an actual inline fan but before I do that, I would like to see if there is maybe anything else I could do to help.

On a side note... I am more active on ICMAG (though gradually coming here more). This is my first grow and the plants' original home is a treasure chest/foot locker turned grow cab. Starting from clones, both plants started off fine and were growing quickly. However, as I started to add nutes, one plant (Docs OG) took it really roughly and got severely nute burnt. After flushing her, she seemed to recover slightly but only to continue to get nute burnt every time I watered/flushed. I don't want to get into all the details here (pH is good, water schedule seems alright, etc...) but if anyone could PLEASE visit the thread and give me some advice, I'd be really appreciative; this place seems to be the more active of the two anyways.

https://www.icmag.com/ic/showthread.php?t=277599&page=2


THANKS ALL!

How warm is the temp outside of the box

jointed said:

How warm is the temp outside of the box

Click to expand...

It is usually 65-75F during the day. Occasionally temps can get to the 80s and even 90s (I'm on the central California coast so really inconsistent weather). However, the lights run from 6PM to 12PM (18/6 cycle) and temps at night are consistently 50-65F.

Add a fan on the intake side and upgrade your exhaust fan is what I would suggest. If there is a colder place in your home you could also move your grow there. ( temps in the mid 40's)

Alright sounds good. I was thinking of using 2x PC fans as intake and then getting an actual inline fan, not a booster, for exhaust. I'll probably use the booster fan for my mom cab which is only 1ftx2ft so hopefully that works! Thanks

You're welcome...J

having your lights on at night and off during the hotter parts of the dayt can help. worked for me and my cab

Maybe putting ur fan outside poiting through intake hole to feed fresh cool air
and yes also a good idea to run ur lights at night when room is cooler rather than when room is hot during daylight
just a thought

Wat r u using as reflecter hood?

Drain grate is restrictive. Replace with a dust shroom.

I have a couple of questions, on where are you taking the temp at. I looked through your photos and I didn't see any thermometer. Do you know what the humidity is inside the cabinet? Airflow in a box your size is also important. Intake and output needs to be somewhat equal in cfm's. Sorry stoned writing this so bear with me. Light a match near the intake and with the cabinet door closed and see if the draft going in the box will take out the flame. Then try same experiment with the exhaust fan. Good luck with your grow!

maybe you could try placing the intake near a drafty window or A/C vent my cab is so similar to yours I keep it near the window and it helps pretty well. Best of luck there looking really pretty

Your intake needs to be 2x the surface area of your exhaust for a passive intake to work properly.

Active intakes for small areas create far more problems than people realize and aren't really necessary.....2ndly where are you taking the temp reading @?

Can you put the intake in the floor? Best way to light proof without using a restrictive light trap. You can light proof your intake with a grate [reduces airflow] or a baffle that will intake air 90 degrees relative to the plane where the intake sits now.

imho, another 12v DC fan for your exhaust added to the existing one could work or upgrade to another blower style exhaust altogether, but do that first while sizing the proper intake.

Active intake as a last resort. KISS

Thanks everyone for your replies.



As mentioned earlier, temperatures are being taken at roughly soil level. Looking at the picture of the full cab, the temps are being read roughly 10 inches off the ground and 12 inches from the lights. That's why I'm even more concerned because if it's that hot there, the top of the canopy must be ~100F or more!

TreeHyde said:

having your lights on at night and off during the hotter parts of the dayt can help. worked for me and my cab

Click to expand...

Also, the lights are NOT running during the day as some replies have seemed to imply; they run from 6PM overnight up to 12PM the next day.

SnapsProvolone said:

Drain grate is restrictive. Replace with a dust shroom.

Click to expand...

Currently the passive intake is about 2x or more than the exhaust. However, I think snapsprovolone point about the drain grate being restrictive is definitely something I can fix.

DankkAbuser said:

Wat r u using as reflecter hood?

Click to expand...

I'm using some ducting/pipe. Kinda like this but rather than actually being a pipe, it was a flexible sheet that could be fastened at both ends to make a pipe. I just cut out pieces that worked for me. $4 each http://www.homedepot.com/p/Speedi-Products-3-in-x-24-in-Aluminum-Rigid-Pipe-30-Gauge-EX-30AP-324/202907099?N=5yc1vZc6hn

Maxed Out said:

Light a match near the intake and with the cabinet door closed and see if the draft going in the box will take out the flame. Then try same experiment with the exhaust fan. Good luck with your grow!

Click to expand...

Hm, sounds interesting. I'll definitely check that out tonight!


Anyways, tonight I'm going to be installing a PC fan in each reflector. Hopefully this will keep the airflow going from bottom to top and make sure that the air around the lights can be as cool as possible. Also, I'll try modify the drain grate to make it less restrictive; I just don't want to pay $10 for a 4" flange haha, and just briefly looking at dust shrooms, I don't think that works best for my situation.

Again, thanks all for replies. I'll post an update tonight.

WOOHOO!
So tonight I cut up the drain grate so it's pretty much a clear hole the same diameter as the fan so no resistance! I also moved the lights a bit higher up; they are a little higher than I'd like, ~6 inches from the top but I'll live. Anyways, the temps are running at 79-82F which is much better than 95F. Again, this is measured at soil so it may still be a bit too hot at the top of canopy. I'll run it overnight with the door cracked a bit and see where this can go!

That's definitely better KB, 73 -75 deg. would be better though. Let us know how it goes. Cheers....J

When I started my micro grow I thought that more exhaust/intake fans with huge CFM values would do the trick. During my first grow I did lots of tweaking and adding more fans was not the trick. After my first grow I found out that placement is the key. You first need to find out where your hot spots are in your grow box.

My friends have done this by using a heat spot gun (forgot the correct terminology for it), but I did this by just having the lights running and feeling around with my hand where there was a noticeable difference in heat and then placing my fans there as an exhaust. Your exhaust fans are going to be the most important in your micro grow. Just because you have exhaust fans near your lights doesn't necessarily mean that it's dissipating all the hot air; you have to find those hot spots.

Your intake fans can be placed anywhere near the bottom of the case where the air is cooler. By properly placing my exhaust fans where they needed to be I was able to drop my temperature from 104 with lights running and no A/C in the house on a 104 degree day outside down to 88 and all I have are 3 fans all together (two 80mm exhaust fans at 35CFM a piece and one 120mm intake fan at ~68CFM) with 4 26w bulbs in a 16" H x 16" L x 7" W case. At one time I've had my case riddled with holes and openings with 6 fans going and was still running temps around 96-100 prior to properly placing my exhaust fans.

Taking a look at your light placement you may be better off taking that exhaust fan and placing it right above your box in the middle of your lights that way youll be venting the hot air from above your case. So place your strongest fan at the top of your case right in the middle as your exhaust.

Also you may want to invest in a cool mist humidifier (only $28 at walmart); seems like you have the room.