4.08.2008

Make your own rain barrels

It's still the rainy season in Central Texas, but you'd best anticipate your plant's needs, so we're thinking about water now, before it's not so easy to come by. To that end, we've been experimenting with various uses for the plastic barrels we picked up last year. Our irrigation system to water our main garden gets more complicated by the day, and I'll detail it soon, but this project is an easy one that can help any size garden. Many urban centers offer subsidized rain barrels for purchase, so make sure to check before you go to all this trouble. That said, barrels purchased from most city programs cost between $50 and $100, and some limit you to one per household; smaller towns rarely have such programs (ours doesn't), and buying one from a commercial vendor will run you around $200. This one cost $12 to make with just a few specialized parts, a couple of tools, and a couple hours.

Our ingredients for this project are almost all shown above: A watertight plastic barrel (this one is 30 gallons), a spigot of some kind with a 3/4" outlet, a drill with a bit slightly smaller than the spigot's inlet (this one's 1/2"), a couple of metal nuts (we bought ours in our local home improvement store's electrical section, where such things are used to make conduit pipes waterproof), and a couple of appropriately-sized rubber washers or a grommet (split the grommet in half with the knife to make two narrower pieces). You'll also need a circular saw, a keyhole saw, and a pair of pliers or vise grips. If you don't have a circular saw I'm sure you could manage this with a nice sharp hand saw.

Other materials you will need depend on how you're siting your barrel. More on that below, this list is starting to sound long.

If you use a circular saw don't cut it like this. My able assistant held and slowly rolled the barrel while I handled the saw. I cut around the top of the barrel 95% of the way, leaving a small amount uncut so that the top opened and closed like a lid on a (bad) hinge. This was necessary in order to reach inside the barrel to tighten the inside nut that secures the spigot to the wall of the barrel.

Next we drilled a hole in the side of the barrel, quite close to the bottom because we knew we'd be raising it up off the ground to increase the pressure. We threaded a metal nut and then a rubber seal all the way onto the spigot, screwed the spigot into the hole, and attached the seal and nut to the other side, tightening with the pliers but not so tight that the grommets get distorted and lose their seal. Work up a little Zen attention and don't overdo it.

Here's where those other materials come in. I wanted to feed water to the rain barrel from a part of our house's lackluster gutter system (I installed gutters along most of one side of our house, then quit because gutters are just so expensive). Part of the gutter was not sloped properly and so water pooled and then overflowed a nearby end cap, far away from our cistern. This area also overhangs a concrete porch and this seemed like the perfect place to locate a rain barrel that we could use to water a small herb garden around the corner, far from our main vegetable plot.

So I also bought a couple of gutter elbows, a "T"piece for a downspout, a 10' length of downspout and a couple of hanging brackets. We figured out about where we wanted the barrel to sit on a 36" tall cinder block base - I don't care what the townies say, it's always nice to have some spare cinder blocks laying around - and eyeballed where the downspout would need to head into the barrel. We marked this with a Sharpie, drilled holes in the four corners of this shape and then cut it out with a keyhole saw.

Below, the end result. It will supply 30 gallons of water to our small front herb and flower garden, our potted plants, and our purchased plants that haven't yet made it into the ground.
If you have nice landscaping and you'd like to preserve its visual integrity, make sure to situate this in a corner or near a wall and try wrapping it in a reed screen and/or painting the barrel a dark color. The latter is okay for a shady location but probably not a good idea for a sunny one. If you try to hide this kind of thing with tall-growing plants you'll just draw attention to it, and bushes are a bad idea because you need easy access.

In our next installment I'll detail our drip irrigation system, which owes its water to both gravity feeding and a pump. It didn't work out quite as we discussed in this post - it's better!

4 comments:

MamaBird said...

this post rocks - and a local metroblogger just yesterday noted that you can pick these up from pepsi plants (if you've got one nearby) for $5 -- http://dc.metblogs.com/2008/04/07/my-barrels-let-me-show-you-them/

Joshua McNichols said...

I recommend screening the top of the water with screen door fabric. All the rain barrels from the city government here in Seattle include mesh to prevent newly hatched mosquitos from emerging. It's part of the effort to cut down on West Nile Virus.

The way they do it here is the downspout dumps onto the lid, which is shaped to drain to the center. Then that hole in the center (a large hole, about 6 inches diameter) is completely screened with screen door mesh.

Jeremiah McNichols said...

Good point, Josh. Ours will be duct taped both around the edge of the lid (we won't need to get into it again) and at the opening where the downspout enters the barrel, once I get some duct tape. The small openings in the lid will be covered with small screw lids that came with the barrel. With the heat we have down here an open screened top would lead to a lot more evaporation than we'd like.

My guess was that mosquitoes wouldn't make it all the way down the 6' of angled downspout into the barrel to lay eggs. Think I'm underestimating them?

In our cistern we use a product called Mosquito Dunks, which contain a naturally-occurring biological larvicide that keeps the eggs from hatching. We'd rather not have to do that in 55-gallon barrels though, because we're cheap.

Joshua McNichols said...

I think the mosquitos could make it through the downspout, but that's just my hunch. But surely they can squeeze between the downspout and the barrel? It's not airtight and they just need a millimeter or so. The nice thing about cutting the downspout short and then screening the top of the barrel is that any debris that washes off the roof just sits on top of the barrel and you can brush it off as you pass by.

Another consideration: especially with a clear barrel, you'll probably need to clean it out every year or two as algae builds up inside. A good reason not to seal the lid shut. I usually let it build up but after awhile it gets so thick it can plug up the spigot. I don't clean it thoroughly, just scrub it a bit and hose it out.