Vertical 360 Light Micro Grow Box

[timmur]

Hi All,
I'm in the process of building a micro grow cabinet and am looking for input regarding cooling/ventilation. The cabinet dimensions are 16" x 16" x 65". The lights are 48" Sun Blaster T5 HO's with reflectors. Only 3 of the 4 are mounted, but the other one will be mounted centered on the door and positioned at top like the others. The hydro setup is General Hydroponics WaterFarm Drip system. The cab is designed to grow one plant at a time and maximize its yield. No need for stealth and it doesn't have to be light proof as it will sit in a light and temperature controlled room.

Basic Stats
Total watts = 216
Total Sqft = 1.77
Total Cubic Feet = 9.57
Total Lumens = 20,088
Watts/sqft = 122
Lumens/sqft = 11,349

My thought was to vent at the bottom with twice the area of the fan inlet at the top but I'm not sure how much fan I need. It seems like not much. As the cab only has about 9.5 cubic feet of volume getting the required air changes per minute (1?) implies a very small fan. Cooling may be a different matter. Any ideas on how I should approach the cooling/ventilation? I would also welcome any feedback in general regarding the overall design. Thanks.

 

[timmur]

Nothing? Well here's a shot with the additional light. Still need to figure out ventilation/cooling. Thoughts?

 

[QLTYlab]

cool idea curious how it turns out

 

[timmur]

I' m going to try to grow Zamaldelica when I take this on it's first run. Waiting for seeds now and I still need to get the ventilation/cooling in place. When I get the seeds I plan on starting thread to document the grow. I really have "high" hopes that this style of growing produces good yields, lol! We'll see.

 

[Purpz]

Damn, that's a tight grow space!

 

[Grow Up]

I'd put in at least a couple of PC fans. But I've never grown in a unit like that before. Honestly, those dimensions don't seem ideal. Too narrow and too tall for the width.

 

[timmur]

Honestly, those dimensions don't seem ideal. Too narrow and too tall for the width.

Maybe. I guess that remains to be seen. The dimensions of the cabinet were carefully chosen to maximize light intensity (or delivery of PAR) to a single plant using T5's. I did a bunch of research on grows that utilized florescent lights and it seemed to me that the successful ones kept the lights very close to the plants throughout the grow. With a 16" x 16" design the plant is never more than 8" inches from the lights. As the plant fills out the distance becomes closer which will deliver even more light as the grow progresses. This also means that there will be no popcorn buds on the bottom of the plant as light is available equally from top to bottom. Also plants grow bushier from the fluorescent lights and high lumens which should improve yield.

Another reason for the strange dimensions is to facilitate growing stretchy pure sativas. I'm not interested in growing indicas or even most of the popular hybrids. The original design was still 16 x 16 but it was about 2.5" tall. I figured it would be hard to constrain the stretch and by going taller I should get more yield per harvest. This idea of 360 degree light with florescents is far from original. I'm not sure of the policy on posting links to other forums, but if you enter "the high-pod" into Google you'll find an interesting grow log that was the inspiration for my cabinet. I'm not sure how well it is actually going to work in practice, but some thought certainly went into it. "The proof is in the pudding" as they say so we'll see how it really pans out.

@Purpz
Thanks! I posted up here and didn't get any responses for quite awhile which was discouraging.

 

[Ambre]

You need a fan at the top to draw the hot air out. The CFM needed on the fan is determined by how much heat your lights put out. Sometimes you can get away with using a "booster" fan designed to be mounted part-way on a long duct. The CFM on the box of the booster fan is based on taking air that is already moving and keeping it moving down an extended length of duct - using it as an only fan will not give you the same CFM as you will get using it as a booster. Some booster fans will also tell you the actual CFM if you are using it as the only fan rather than as a booster fan, so read everything on the box.

As small as your box is, you might also be able to use one or two computer-style fans. If you go for this option, use larger size fans, not the small ones.

If heat is a problem in your room, you can attach ducting to the outgo to carry the heat outside (if you want to make a hole for the ducting) or to carry it out of the room (I have a vent in the top of the door in my grow room so I can duct the heat out to the hallway).

Air intakes should be at the bottom of the cabinet. This way, the air pulled in is as cool as possible (since heat rises, the coolest air in the room will be at floor level). The area for intake should be at least double the size of your fan (if you have a 4" diam fan, then you need two 4" diam holes or equivalent for intake).

 

[Purpz]

@timmur you're correct that while using fluorescent lights the lights should be as close to the plant as possible. Will be interesting to see if things go as you're planning. More room for spread would be better.

 

[timmur]

@Ambre
I think I'm going to use an Active Air 4" inline fan and a speed controller. 4" duct up top and two 4 inch ones towards the bottom. The calculator I used said that I need about 140 cfm to cool the cabinet to 5 degrees above ambient. My only concern is that that is at least 10x more ventilation than the plants actually need. According to some people this will stress the plant. I guess I'll try it and see as I can't figure out how to meet such widely different air needs.

@Purpz
Yes, in some ways I wish I had gone a bit bigger on the footprint.

 

[Ambre]

You can cut the CFM's using the speed controller. The throughput you need will depend primarily on the temp of the air being pulled in & the amount of heat your lights put out.

You might consider putting something over the lights to keep your buds from touching them. A piece of hardware cloth would work well, it's easy to curve to fit around the lights. You can get hardware cloth at most big box stores - it's usually in the fencing area of the garden center.

 

[Ambre]

Yeah, I thought about the Phototrons when I saw this. It will take a lot of trimming and training to get a plant to grow in such a narrow and tall space. There really isn't any elbow room in the box, especially once the plant is growing in there, it might be necessary to pull the plant out of the box in order to work on it. A trellis to train the branches on might be useful, but to get any light penetration into the plant, all of the fan leaves will have to be cut off and growing tips will need to be kept to a minimum. I'd be tempted to drop some CFL's into the center to give more light. But hey, it's a cool project and Timmur will figure out how to improve the design for the next one. Most of the components can be recycled into other projects.

 

[timmur]

Ambre, you're right it will be work to keep it trimmed, but I do plan to pull it out of the cabinet to work on it. All of the pruning should be good for yield so it should be worth the "work"!

 

[Purpz]

No harm in trying. If it doesn't go as plan, build a bigger cab and try again. All part of the fun. :)

 

[timmur]

Well I really hope it works out, but if not I'll re-purpose the lights and try another approach.

 

[Purpz]

Likewise, hoping it works out for you too.

 

[timmur]

Just wanted to drop in and say that this thread isn't dead. The ventilation fan and carbon filter are on their way and will be installed next week. I went with this combo. It moves about 150 CFM and the filter is supposed to support that flow. I will probably end up using a speed controller, but I'm going to test the temps first.

 

[Ambre]

Please post up pics & description when you get it & install it. That looks like a nice system for a small garden.

 

[timmur]

Please post up pics & description when you get it & install it. That looks like a nice system for a small garden.

Thanks! I have one more item to finish after the ventilation is added and that is a UV light. I'm going to install a Zoo Med ReptiSun T5 HO High Output Terrarium Hood (the 14" one) at the top of the cabinet for a good dose of UVB. Not sure how long I will run it yet, but probably only a couple of hours per day. I'll post pics up along the way until this thing is built. Then I'll start a new thread to document the grow. I have Zamaldelica seeds now, but not sure if I want to start off with it. I may get a local clone of LSD or Jillybean and get my feet wet with one of them first. What I really need is good thread outlining the basics on this Waterfarm setup I'm going to use. Any thoughts on the UVB is welcome.

Nice thread on CFL's!

 

[MrBanjo]

Couple of suggestions here: Don't top much, you'll be doing quite a bit of pruning to keep your plants off those lights. Install a trellis cage on your lid, if you tie your plant up for support on wall anchors in your room, you won't be able to move it in and out of such a small space. Make sure you're giving your plants the spectrum they need depending on the stage of their life.

Good luck and have fun.