OHCULS (pronounced Oh, coolz!) is an inexpensive, efficient grow light system intended for small closet grows for individual, legal medical marijuana patients (not for “grow ops” or commercial-scale setups). Heat and electricity usage is minimal, so it makes things simpler than almost any other method. The OHCULS concept will work with any indoor growing setup, not just cannabis. Here are the main features and benefits of Old Hippie’s Compact Universal Lighting System:

inexpensive

modular – make it larger or smaller as needed

very efficiENT – uses compact fluorescENT (CFL) bulbs

lightweight

you can remove bulbs as needed to give plants more room

can run a whole closet grow, using every bit of available space

you shouldn’t need ventilation or have to worry about electric usage

I know that lots of people have philosophical problems with using CFLs to grow plants. The beauty of this approach is that, as CFL technology gets better, you can replace the bulbs I’m using with better bulbs if you like. EvENTually, someone will get the bright idea (groan!) to sell LEDs installed in standard-base bulbs (in red and blue for growing, of course) and then you can plug those right in here too.

The most important reasons for growing using these particular CFLs are:

1750 lumens, 5000° K daylight color temperature, 27 watts

being CFLs, they run relatively cool so you can put the whole shebang 3 inches away from the plants without burning them

they are on semi-permanENT sale at 2 for $1.98 (at least at my Home Depot!)

CFLs in theory are not as electrically efficiENT as sodium vapor or metal halide HID lights, but by putting them right next to the plants, you’re making up for it with lots more delivered lumens. I’m using 8 bulbs, which comes to 14,000 lumens and 216 watts.

I invENTed this lighting system for a buddy of mine who grows his own medical marijuana, after being inspired by a picture on /r/trees of a compact grow operation that included a light made with a PVC tube. I had just made my buddy some lights out of “classic” electrical componENTs, but they had a number of disadvantages, mainly cost, weight, and capacity. When I saw PVC tubing, a light bulb went off in my head. After seeing a doctor and an electrician for this problem, I proceeded to my local Home Depot, where I bought the following items:

rubber-encased “pigtail” bulb sockets

EcoSmart 100 watt equivalENT daylight CFL bulbs

24″ PVC tubing, 1¼” diameter

1¼” 4-way quads/crosses/helicopters

#3 double loop chain (industry standard!)

thick gloppy adhesive of your choice (Gorilla Glue, epoxy putty, or even Sugru)

The tubing and the crosses are found in the plumbing departmENT. You’ll also need some regular “zip cord” for wiring, and a plug (I just cannibalized an older light cord), and your choice of either wire nuts or solder for making the connections. It gets a little crowded in those tubes, so I decided to solder. Oh, and while you’re in the electrical department, scout around and you’ll find that Home Depot also has timers for only $3.95 or so that are more than adequate for this use.

The “tee” shown in the photo was for my original design, for which I was going to use 6 bulbs. Then I got more excited and decided to go for 8 bulbs, so I bought more bulbs and sockets and another 4-way “cross”. Without further ado, here’s what the finished fixture looks like:

And here it is in operation:

With the incandscENT equivalENT of 800 watts of light, this thing is blinding, so I underexposed the picture so you could actually see the lights. It’s a pretty amazing amount of distributed light (as opposed to most “pro” fixtures that actually only put out their light in a small area) for a total cost of less than $40 (including the chain!).

Putting this thing together is pretty easy and kinda fun, too. The PVC all slips together tightly enough so you don’t really need glue or anything to hold it together, either.

The main thing is to measure the space you have to determine how long to make it, and don’t forget to allow for the length of the bulbs at the ends (like I almost did). The actual “cross” fittings will add 3½ to 4 inches to the tube length on each end (plus don’t forget the middle one). Allow room, especially on the ends, because as you can see the bulbs have no protection, and you don’t want them smashing into the side of your closet. My prototype OHCULS specs are as follows:

Closet space: 40″ x 23″

OHCULS: 34″ x 13″ (with bulbs).

Total length of the tubing and fittings alone is 25″.

After I had eyeballed everything and then checked it all out on paper, I got out my trusty hacksaw and cut the tubing into three equal parts of 8″ each, then removed all the crud at the ends from sawing with my handy ninja assault knife (well, it’s black, anyway).

Then I laid the tubing aside for awhile and tested all the sockets with a meter, figuring it would be hard to return them as defective after I permanENTly glued them into the PVC fittings…also I had gotten a bunch of socket extenders at Home Depot that were 80% defective and was therefore a bit wary. It must have been that particular Chinese supplier, because I had no problems with these sockets.

Then I started gluing the sockets directly into the PVC fittings. We can get away with this trick for two main reasons: (a) because CFL bulbs don’t create a great deal of heat down by the socket area and (b) the socket’s outside is almost (but not quite) the size of the fitting’s inside! I initially started by using silicone glue, but soon found that it doesn’t really adhere well to the rubber-coated sockets. Then I remembered that Gorilla Glue, which sticks to almost anything, has the property of expanding (puffing out, actually) when the surface has been dampened. I sprayed a fine mist of water on the back of the socket and the inside of the fitting, and used a baby syringe in an attempt to keep the mess down. It worked, although it took awhile to dry so I had to keep propping up the wires coming out of the back of the socket so it would remain straight while drying. Next time I will just use 2-part epoxy putty and it will be much easier. But whatever you do use, it must fill the gap between the socket and the fitting. Take your time and make sure each socket is in firmly and the adhesive dry before adding the next one. Picture time, already!

OK, now it’s time to wire things up. Don’t laugh:

I left the tubing out of the picture to avoid confusing you even further. For those who are schematically challenged, or whatever, it doesn’t matter: all you do is connect all the black wires together from each of the 2 or 3 sockets in each of the quad/cross PVC connectors, connect all the white ones together too, and use the extra 2-conductor zip cord to hook each set together through the tubing, and to the line cord that plugs into the wall (actually, the timer). You’ll need an extra extension to get “one side to the other” across the middle cross. You don’t have to be a genius to wire this…it’s easier than coughing the cherry out of your pipe 🙂

Since the whole thing is based on balance, you have to keep the number of bulbs on each side the same, even if you don’t fill up all the sockets. If some plants start growing too tall in one place or another, unscrew the corresponding bulb just enough so it turns off (but not so much that it falls out). This will keep the fixture balanced so it doesn’t spin vertically.

Another trick we used is to create a reflector to push more light straight down to the plants, rather than uselessly up in the air. We took a piece of Reflectix and cut it to size, then installed it by making an “X” through both chains with kabob sticks (because it’s rather floppy), punching holes through the Reflectix for the chains to pass through. The finished reflector (which is kind of hard to photograph properly) sits about 4 to 6 inches above the OHCULS fixture.

Ghetto? Maybe in looks. But it all works pretty damn well. And there’s nothing like making your own stuff…especially when you’re growing your own stuff!