10 October, 2008

DIY Drip Irrigation

Drip irrigation is an excellent water-saver, and it's good for your plants too. It allows precise, measured delivery of water to the roots of the plant, helping to prevent watering nearby weeds, or encouraging bolting on certain plants which respond badly to being watered from above.

Bunnings (the Aussie Home Depot) currently sells pre-drilled 30 metre drip irrigation hoses for around $37, and that's just the beginning. Add in fittings and stoppers, timers, and all the other things their project books insist you need, and you could easily drop as much as $100 on just one length of watering hose for your veggie patch. Here's how we cut the total cost under $7.

30 metres of black, UV tolerant poly tube - $4.95
1 stopper fitting - $0.60
1 tap-attachment fitting - $0.60
1 small, sharp metal nail - Free from our hardware stash
A dozen or two metal tent stakes, or similar - Free, but others might not have these laying around.
A hammer
Potentially a saw or metal grinder of some sort, but we'll get to that.

First, stretch out the full length of tube to straighten it as best you can. They come coiled, and they like to stay coiled. Next, step back from your garden and get a real visual plan of the best route for laying your irrigation. Remember, one end needs to attach to a water supply, or the project kind of ends there! Bonus points if you can hook it to a rainwater collection tank, or greywater system if you're irrigating established, non-food plants.

Grab a friend and start laying tube, with the goal being to get the base of every plant exposed to some part of your irrigation system. Use a hammer to nail tent stakes into the soil, with the crooked end acting as an anchor for the tubing.

TIP: If, like us, you don't have enough tent stakes, or your soil is too soft for stable anchoring, make your own anchors. We had excellent luck cutting up an old, unwanted, rusty metal trellis "gifted" us by some previous homeowner. The hubby cut them into a large U-shaped bracket and they worked like a charm!

Once you've secured the tubing to the ground put a stopper fitting into the far end of the tube and, you guessed it, join the tap attachment to the tube and the tap. Now, grab your trusty (but not rusty) nail and get to stabbing! Start with one hole for every plant or clump of plants you'd like to water. If there are just too many, sparsely perforate the tube as needed. If there's nothing planted along a section of tube...don't poke it! Save water where you can. For planted mounds, I prefer a low "rainbow" of tube overtop to trying to wind the irrigation around the whole damn thing.

Once everything is stabbed and poked, turn on the tap. But be careful--Your peaceful little drip irrigation system can easily become a geyser if the pressure is too high. And if you feel you absolutely need a two-hour timer for your tap, that should only bring the project total cost up to $16 or so.

Congratulations! You just built your very own drip irrigation system! Now that you know how to do the basics, on the cheap, you can experiment with adding offshots, T-joints, L-corners, everything you need to flawlessly water your entire patch.

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