Making the Switch to Drip Irrigation

An emerging green-consciousness, ongoing droughts in many parts of the country, and the realization that water is likely to become increasingly scarce in the future is leading to a boost in the popularity of drip irrigation.

Installing drip irrigation lines is far easier than installing a sprinkler system because most of what you are installing is above ground. To do so, you need:

• Pressure regulator
• 1/2-inch flex-pipe
• 1/2-inch drip line with internal emitters (you can also make drip line by screwing or pushing emitters into flex-pipe, but this involves more work, and the drip line with external emitters tends to be more prone to clogs and leaks)
• Barbed fittings (you need an assortment of tees, elbows, and couplers plus one fitting that is barbed on one end and threaded at the other to connect the flex pipe to the pressure regulator)
• Handful of end stops (these are "8" shaped). Tin shears or a garden lopper are good for cutting the flex-pipe, but a sharp knife and cutting board work as well.

Measure Twice, Shop Once

You want to make at least two passes through your planting bed to determine how much flex-pipe and drip line you need. The first time, simply do a loop or loops, measuring the shortest route through the area that comes near all of your plants. This determines the amount of flex pipe you need.

Next, tally up all of the different plants you plan to irrigate, using the following guidelines:

• For flower beds, measure your rows of flowers and include a drip line the length of each row
• Small bush or plant--allow 18" for each one
• Medium- to large-sized bush or small tree--allow 3' for each one
• Large trees--allow 6' for each.

Add it all up to determine how much drip line to buy. Also, you need two tee fittings for each plant/flower bed row. Get about a third as many couplings and elbows. And plan on getting about 15 percent more of everything than your measurements indicate to ensure you don't run out of anything.

Locate the Beginning of the Line

You want to tap into your irrigation line near the first sprinkler head in the zone. (If your drip line will be a new zone for your system, you need to add a valve and run a PVC line to the edge of the new zone.) Generally this is the sprinkler head closest to the valve box. Test by removing what you believe is the first sprinkler head (dig around it so you can get a good grip and then unscrew it). Manually start the zone. All of the other sprinkler heads should have noticeably diminished flow because all the water is shooting out from where you removed the sprinkler.

If not, determine which of the sprinkler heads with normal flow is farthest from the one you removed, and repeat the test after removing that one. Once you have determined the first sprinkler head, dig around it to fully expose the PVC supply line. (You can just leave the remaining sprinkler heads or remove them so you have replacement heads and parts for the rest of your irrigation system.)

You're Ready to Install

The most difficult task remaining is to cut into the supply line (a reciprocating saw works best, a hacksaw will do) and use PVC solvents to attach the pressure regulator. Use sandpaper to remove any bits of PVC from the cut pipe so they don't break off and clog the drip line. Attach the flex pipe to the regulator and lay it out as previously determined.

Next, cut the drip line in lengths to form a circle around each plant. Use tee fittings to joint the two ends of each circle. Finally, use short lengths of flex pipe to attach the drip line to the flex pipe source line, using additional tee fittings to tap into the source line as needed. If you have any loose ends, use the end stops to seal them. Test the line and fix leaks as needed.