Make your own – grow light edition

March 23, 2011 at 6:55 pm (Uncategorized) (, , )

As I hatched plans for taking this year’s attempt at gardening from truly pathetic to probably-more-than-I-can-actually-handle, I decided I really wanted a way to start my own seedlings, to save money, allow me to use more heirloom varieties, and just because I wanted the experience under my proverbial belt. I’ve started things from seed a few times in my life, sure. Herbs in windowsill pots, with varying degrees of minor success. Herbs in a flat, once, which a certain black cat decided would make a great scented window seat. I wanted to be able to start all those various plants that the books say “start 6-8 weeks before last frost/planting date”. I rapidly realized I would need a grow light this time. Windowsills only get you so far with most plants, due to insufficient light for early growth. Also, cats. My elderly tabby-co is a terrible plant muncher, and I only have one room she doesn’t frequent right now, which is only closed for heating efficiency in the winter.

So, plant light in the unfinished basement it is. Commence shopping. Or not. A few attempts to research the best models available rapidly told me that, for the most part, the really good ones with a decent amount of space coverage and enough light were going to run _way_ past my very limited budget. The ones I could afford? Small, flimsy, bad reviews, and probably not going to start enough plants to make it worth the effort. Okay, time to think about design.
In a glorious bit of serendipitous timing, while I was considering this, I happened to pick up the most recent issue of Urban Farm magazine. Oh look, build your own grow light! How Handy!

Why, then, am I rambling about what I did, instead of simply telling everyone to go find their version? Because we changed it, and here’s why: It may be a little cheaper, but I did not want that much PVC on my guilt list or in my house. That simple. Now, I freely admit that if the black iron, which is what I wound up using, had been twice as expensive, or more, we may have used the PVC anyway, just because the budget is that tight. But as it happens, we price-checked, cross-checked, multiple stores and all, and it wound up only being 15-20 dollars more, and I was okay with that. (Yes, I know, it’s not like iron pipe is environmentally clean, but at least it, in and of itself, is not a product of a toxic gas or petroleum. We do what we can, and live with what we can’t.)

So, with apologies to Urban Farm magazine, here’s my shopping list:
-2 x black iron pipe, 1/2″ x 10′
-4 x black iron elbow to fit 1/2″ pipe
-4 x black iron tee to fit
-4 x black iron cap to fit (technically optional, but I could see bugs harboring in the open ends, so I chose to cover them)
-2 x basic shop fluorescent light fixtures, 2 bulb, 48″
-4 x 48″ fluorescent bulbs, with a K number over 6000 – I found a 10-pack of daylight bulbs rated 6500K fairly cheap (some people advocate a mix of cooler and warmer light for seedling raising, other will insist on the grow-light bulbs that are specially marketed. This was cheaper, was what Urban Farm said would work, and it’s working just fine so far)

Chain and s-hook to suspend the fixtures from the frame should be included with the fixtures. You’ll need some way to hook the chains to the pipe, however – we used some decently strong steel wire that we already have around. Larger s-hooks can be purchased pretty cheaply, if that’s easier. Most stores charge a fee for each cut and thread of black iron pipe, so unless you have a cut/thread tool yourself, plan to budget that in, and I found the price ranged from 1 dollar per cut and thread to 1 quarter per cut or thread, and if you get someone working the machine who is in a good mood, they might charge you less.

Prices will vary based on where you are, of course, but roughly speaking, the pipe was under 20 for both lengths, the assorted fittings came in at around $15 total, the 10-pack of bulbs was 25, and the shop fixtures were around $10 each. Note that these shop fixtures do not have large reflectors to gather light and aim it down. Fixtures like that are available, but the price difference was enough that I chose not to go that route. I will simply make my own reflectors out of heavy-duty foil if I need to. Also, many times shop light fixtures can be found at re-sale stores for habitat for humanity, or other construction re-use shops, and maybe even estate sales and similar. If you’re got the time, by all means scavenge for the supplies! Re-use is valuable.

The major assembly difference in choosing to make this out of iron pipe instead of PVC was that the joints were no longer slip joints, but threaded. This definitely makes assembly a two-person gig, as getting that last piece in place involves that fun challenge of not unscrewing the other end while you fasten it in. But while it’s a rather loose frame when carried, it’s nice and solid on the counter-top it currently resides on, it holds the lights easily, and I find it more attractive than PVC (ymmv).

So here’s the basic idea. Take the two 10′ pipes, and cut each of them identically. From each one, you want one 52″ length, one 14″ length, two lengths of 24″, and the rest evenly split – I’d say do the math, but the fact is, it depends on how much pipe is lost in each cut. Those last little bits are just little stabilizer feet. As long as they’re sufficient to be threaded into place and provide a base, you’re all good. These numbers can all be adjusted slightly – the idea is use the entire length of pipe, no waste, and make sure it’s long enough to freely support the shop light fixtures. How tall you go (the 20+ measurement) and how far apart the light support bars are (the 14″ measurement) is actually adjustable. Remember, the lights can be raised and lowered by really cheap chain, too, so don’t panic about exact height.

For assembly, picture a set of gymnastics parallel bars made for a toddler. No, seriously. Each 14″ piece has a tee joint at each end. Extending out is the small stabilizer piece, and upwards from each tee is the 20-something inch piece. At the other end of each 24″ inch piece will be an elbow, into which fastens a 52″ piece. Elbows again on the other side of those, and on back down in a vaguely symetrical fashion. Best way to put it together? Beats me. I’m not an engineer. But I can say that the last piece we put in was the 14″ bar on the other side, and the trick to it (alright, the main trick to it) was screwing that piece in as far as we could on one side, so that when we screwed it into the tee joint on the other side, it wouldn’t unfasten itself in the process.

It’s simpler than it sounds, really. Who thing, from going to the store, picking up the parts, waiting for cutting, and assembling it in the driveway to be carried around to the back door? Maybe an hour, hour and a half. Most of that was waiting for the cutting and threading. Adding the lights is a simple matter of hanging the chains from the pipes, putting the s-hook on the other end, and suspending the shop lights from the hooks.

All told, a couple hours of time, not counting the research and pre-shopping and designing, and it cost us around $85, with enough spare bulbs to last for years. As I said earlier, I suspect it will pay for itself within a year of use by producing healthy plants I don’t have to buy individually, and I’ll be doing math along the way to see if I’m right.

One additional expense to consider: a timer. If you already have one, you’re set to go. If you don’t, you have to decide whether to be diligent about turning the light on bright and early every morning, and turning it off every night, or buying a timer to do it for you. Most books I’ve looked at suggest 16 hours of artificial light per day for seedling growth. Just leaving it on all the time, though, will also kill them, since they need the dark time as well. We had an old timer, but since there were two lights to be plugged in, and a very limited number of outlets in the basement, we located a decently priced multi-outlet power strip with programmable timers. I have it set to come on at 6am, and turn off at 10pm, and I don’t have to think about it, or worry if I’m out late (or more likely, not up yet when it needs to be turned on). That cost us another $20 or so, but saves me endless worry, and should last for a nice long time, as well as being usable for other purposes if I ever again have a season when I’m not using the grow light.

Next blogging goal: pictures of seedlings! I know I can get pictures into this thing, really I can. Maybe.

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