Help me with a light barrier, pleease.

[GardenCaress]

I have a closet about 9' tall. and I have plants flowering in that closet. I want a little veg chamber, so I threw a tray up there with a couple hoses and put it under a T5

I need to ensure no light escapes from the T5 to the flowering plants below. I have tried covering the sides with trash bags, two layers thick to stop light penetration.

All temps with 400w CMH with reflector, uncooled (but will be very soon)
T5 off: mid 80ºs
T5 on without trash bags: low 90ºs
T5 on with trash bags: 103º

I hope the addition of separate cooling for the lamp with reduce heat by about 7º, however, I need to integrate a fan into whatever can serve as a light barrier to keep a flow of air going.
What material should I use for a light barrier? cardboard? mylar? wood? rigid, flexible? some sort of fabric? I was hoping you might have some ideas to help figure this out. Gracias, everyone

 

[squirrelfooker]

Small duct work or pvc with bends to stop light, and a fan attached to it. Poly plastic and tarp zippers or velcro to separate it.

 

[Haps]

what he said.

 

[GardenCaress]

Small duct work or pvc with bends to stop light, and a fan attached to it. Poly plastic and tarp zippers or velcro to separate it.

Thanks for the advice but what do you mean by duct work? Or PVC with bends? Sorry for not getting it!

 

[fatigues]

Thanks for the advice but what do you mean by duct work? Or PVC with bends? Sorry for not getting it!

He means use something like panda plastic as your main light barrier. Top, bottom, and four sides. It's a plastic cube which will stop all light from passing out or in.

In order to get inside of that area you have now enclosed off in plastic, you'll want to install a zipper or use velcro to act as a means of opening/closing your door when not in use. Think of it as a tent with a zipper, ok?

But if that's all you did, you'd suffocate your plants in your grow. You need to provide them with a means of getting air, when that door is zipped up. You need to make the enclosure light tight, without it being air tight, too.

The standard way of doing that is to use to PVC pipe elbows, shaped in two "U" pieces, attached in the middle at one point with the other two ends facing in opposite directions, one outside and one inside the area that needs to be supplied with air.

Imagine a standard "U" water trap at the base of a drain. Got that in your head? Now, imagine attaching another "U" attached to one of those holes in the pipe, so that you now have an undulating curve of PVC pipe.

That two curves in the middle of that undulating piece of PVC acts as a light trap. Air will flow through it - light will not. Install one of more of those light traps as passive air intakes for your new plastic enclosed grow space.

In many case, if the insides of the pipe are painted black and the pipe is long enough - a simple "u" (without adding another to it) will be enough to block the vast majority of any light getting in. It's up to you how thorough you want to make your light trap.

You'll need to have a fan in your little plastic enclosed grow area to draw air through those intakes - and to exhaust air outside of it, too. Otherwise, not only will you cook the plants in your new enclosed off grow area - you'll suffocate them too.

Make sense now?

 

[GardenCaress]

That does make a lot more sense, thanks for the post! I'm going to go to the hydro store in the next couple of days and see what they got that can work.

 

[Hydro-Soil]

That does make a lot more sense, thanks for the post! I'm going to go to the hydro store in the next couple of days and see what they got that can work.

Save yourself $100 and go to the hardware store first. Only go to the hydro store for inline fans and such, all the regular 'hardware' like ducting and such is usually way overpriced.

 

[squirrelfooker]

Save yourself $100 and go to the hardware store first. Only go to the hydro store for inline fans and such, all the regular 'hardware' like ducting and such is usually way overpriced.

Agreed, you can even get the fan you need there. For a fan to do ONLY that new partitioned off veg space you could use 4" duct and computer fans, or a 4" booster fan found in the ducting section of a hardware store. The fans cost around $20. You could go smaller, but smaller can get hard to find.

You must stop 100% of that light from getting to the flowering room as well.

 

[GardenCaress]

Ok guys I don't have the fan yet but I have put together the veg enclosure with pvc and panda plastic, minus the front. T5 is hanging up there awaiting my bidding.

Now, this is a whole other topic but about air cooling the reflector with the 400w cmh in it that I mentioned in the first post... I asked the stoned lookin guy walkin' the floor at the hydro store and he said an axial fan wouldn't do the job and that I would need an inline fan. But it only has to move air through three feet of ducting and it's venting into my room so I don't want a jet of loud air coming in. I'll use insulated ducting but still. Anybody got ideas on an effective quiet fan? or two?

 

[fatigues]

If you are looking for a quiet fan, you should get a Solar and Palau mixed vent fan, installed inline. S&P TD-100x/TD-125 should serve admirably.

Available at hvacquick.com.

 

[GardenCaress]

I am actually running a 100x pulling through a filter as my primary fan. It does well and moves a lot of air for the closet. I was hoping there would be something smaller that could cool it