First Ever for GardensGrow

Running the ballast outside the grow area will be your best move. It creates as much or more heat than the bulb.

Since your fixture is open-air, you need to direct the end of the ducting as close to the heat source as possible - in this case the bulb. Either route it around the front of the shelf if you can, or put a hole in the shelf and run it through so that it sucks horizontally from the bulb fixture. You can rig something up.

just wanna say for someone just jumpin into it your set up looks good. for less heat i would second the removal of the ballas from the area at least put it up top around the exhaust fan or something. maybe get a bigger fan. good luck on the grow. hope you get your seeds soon. i got mine less 2 weeks through doc chronic, and didnt get em through nirvana, if your in US its a bit of a crap shoot.

Hey thanks guys. I asked about this issue in another thread before I decided to start a grow journal and someone else suggested re-routing the filter/ducting too.

As for the ballast, I was hoping to keep this semi-stealth but with the giant beacon of light coming from underneath the door I think that putting the ballast outside will be the least of my worries.

So I will do both, check temps, snap pics, and post.

Thanks!

Can you get your intake air from somewhere else? You're going to need to seal off that door when you flower. During the dark period it's suppose to be completely dark--no light leaks. If light leaks in they'll be reluctant to start flowering and they could even turn into hermaphrodites (so I'm told).

In my situation I build a cabinet that houses my grow. And the cabinet sits in a closet. It would have been easier to just use the closet itself as the grow space but I didn't have a good way to seal it from light leaks AND keep it looking like a normal closet. It was fine as-is for vegging but I needed the cab for flowering.





FWIW, I'm using a 6" 440cfm fan (with an extraordinary long duct run--about 50 feet of mostly rigid duct), an air cooled hood, a DIY carbon scrubber, and a 250w HID. I believe I've lost at least half the rated cfm of my fan (hard to judge). I also have a cheapy humidifier blowing directly into the grow area through some ducting. That helped bring temps down and raise my humidity to 35-40% (dry climate). My temps are 2.5deg above ambient (typically 80 minus 77.5 but the spread holds at slightly lower temps) ~8" below the bulb . Without the humidifier I believe my temp spread was more like 4, perhaps 5 degrees. My cab is actually a functional prototype that needs some tweaking so I think the final setup will improve the temp spreads. The final version will be a complete rebuild out of permanent materials, a real door instead of a sliding piece of cardboard, etc.

The first pic doesn't really show the whole current setup but might give you an idea of what I'm working with. The second and third pics are from before I got the cab prototype installed. With the pre-cab arrangement my temps where 1 degree or less above ambient. Also, that filter you see lasted about a week before it had to go. I've got a different one now that's more substantial (and restrictive).

My goal is to have enough cooling capacity to accommodate a 400w with no more than a 3 degree temp spread. And I'd like to accomplish that without needing the humidifier when the lights are on. I think I can do that but it's likely going to take the addition of another 6" fan. Dual exhaust fans where part of the original plan (even though I've only got one right now) so I'm ok with that. So much fan probably wouldn't be necessary for most but my exhaust fan(s) are really far away up in the attic (stealth!). Long runs means loss in cfm. Sorry for rambling but your situation reminds me a bit of mine.

I can't really get the intake from anywhere else unfortunately. I rent the property so minimal destruction is best. Altough I've considered buying a cheap door so I can beat on it...

I've got to admit that it's slightly discouraging to see that you're using a 6" 440cfm with a 250 watt and you're at 2 degrees above ambient (you're setup is awesome btw). Considering I'm at 170cfm with a 400 watt I'm thinkin' I've got quite the challenge ahead of me lol. Humidity isn't much of an issue here at the moment. How exactly does humidity affect temperature? Seems like it lowers the temp a bit...

As we speak I'm re-testing the grow cab after moving the ballast out of the room and re-positioning the filter directly above the light. I will post temps and pictures after it's all finished.

Thanks!

~GG

Don't let my setup or results discourage you. My super long duct run hurts the actual cfm being moved by my fan, not doubt about that. And I've read plenty of opinions stating it's not that much harder to cool a 400w vs. a 250w. I must admit I've always read those comments with skepticism--but heck, I don't really know. I'd just keep tweaking your setup looking for incremental improvements. Move things around, add some circulation fans, get the ballast out--I bet it will add up and you'll start getting close.

I experimented with a speed controller on my exhaust fan before I remotely located it into my attic. I found that it didn't take much airflow through the hood (WAY less than full speed) to keep the hood pretty cool. The speed controller made my fan loud as heck though. Plus I want/need as many cfm as possible to rotate fresh air into the grow area. So I run it full speed. But that might mean that if you can suck air from very close to your hood it might make a big difference.

Another option is to make a DIY cooltube as an alternative to purchasing an air cooled hood.

About the door: I do think the larger your passive intake is the closer you'll get to the actual CFM rating of your fan. But 1" by 30" (?) is 30 square inches. That's not too bad in relation to your 4" diameter fan. I bet you can figure a way to light proof it too. I'm thinking a cardboard light-trap contraption could work.

The humidifier does help bring down temps. Last time I stuck my temp probe right into the outlet of the humidifier I believe the air was colder than I was expecting. 68deg if I recall (not many cfm's though). It's basically a little swamp cooler if you're familiar with those (a common item in the desert).

Hawk, thanks for the suggestions and encouragement.

I just got done with a one hour test run and the results were interesting. The temperature this time is actually higher than before; now at 88 degrees.

I think that the placement of the temp gauge definitely has something to do with it as I moved it about two feet below the light (you can see it in the second picture).

The ballast is out of the room (and hot as hell as expected) and the filter is directly above the light...but doesn't seem to be doing much.

The plastic on the floor will be removed and replaced with something else; probably Mylar (good idea?). The plastic actually poofs up really big when I run the fan with the door closed so I know there is suction in the room. Maybe when the plastic poofs up it's blocking the intake...

Any other suggestions before I drop $100+ on an air cooled hood? (after reading some of Jeorge Cervantes's book I'm not too fond of the DIY cool tube shape).

Pictars:
Moved the filter directly above the light and added chains to both


Going to remove plastic and cover floor and door with Mylar

your ducting looks like a curley-q right now, which i'm sure hurts flow.

first, i would put the filter intake at the same level as the light, so you can adjust it with the chain as you move the light, and so the air flow is actually over the light. currently, air has to flow around the entire hood to get to the intake, which is slow compared to creating a flow over it. if you then either cut the ducting or compress it, you'll end up with less effective ducting, and in the shape of something like a "C" or an upside-down question mark, if you get me.