A hassle-free way to water container plants automatically
Since my watering habits are a little erratic, I decided that the best way to keep my potted plants from dying of thirst was to install a timed drip-irrigation system. A timed system eliminates the need for hand-watering, ensuring that plants won't dry out if you forget to water or if you go on vacation.
Intimidated by the prospect of assembling a drip system from scratch, I opted for a prepackaged kit. I chose the Raindrip Automatic Drip Watering Patio Kit (about $40 at garden supply stores). Once I started, it was as easy to put together as a Lego set.
Before you assemble the system, read the accompanying instructions thoroughly. Kits vary slightly from brand to brand; choose one that includes a timer, a filter, a pressure regulator, and an antisiphon device (also called a backflow preventer or vacuum breaker), which keeps irrigation water from being drawn back into the public water system and is required by many localities. If your kit doesn't have all these components, purchase them separately.
Make sure containers are where you want them before you lay any tubing. On a timed system, the plants should have similar water needs; try to use containers in the same size range.
More drip tips
Consider components. Different manufacturers' drip-irrigation components usually aren't interchangeable. If you think you may need extra parts, choose a kit by a vendor that also sells individual pieces.
Measure carefully. It's hard to remove fittings once they're connected, so the adage "measure twice, cut once" applies. You might want to get extra tubing just in case.
Evaluate pressure. Water pressure in the line drops the farther it is from the hose bib. For greatest efficiency when using ¼-inch tubing, don't use more than 50 feet in one circuit with a maximum of 15 gallons per hour of emitter output. For ½-inch tubing, use at most 300 feet of line with 250 gallons of emitter output. (If you use less than the maximum recommended length of tubing, however, you can increase emitter output.)
Check for leaks. Once you've set up your system, turn it on, set the timer, and monitor it for a couple of cycles to make sure all components are working properly. If you notice leaks in the system, either at the fittings or emitters, make sure the tubing is properly fitted. Leaks may also indicate too much pressure in the system.
Watch for clogs. Too little flow could be caused by a kink in the line or particles clogging the emitters.
Flush the line. Every few months, open the end of the line and flush it for about 30 seconds, then reclose the line.