Few gardeners enjoy dragging a sprinkler around the yard to keep the lawn green during summer dry spells. No one has to: a sprinkler system buried beneath a lawn or garden can take over the job. At the turn of a handle or--in an automatic system--the timed flick of a switch, sprinkler heads push up through the grass and flowers to create overlapping umbrellas of spray. At the end of the watering period the heads sink into the ground.
Installing such a sprinkler system doesn't take a lot of special skills. A simple lawn may have all its sprinkler heads on one supply line, controlled by a single shutoff valve. A yard divided into several distinct areas with different watering needs calls for a more complex system with several supply lines, each serving a single watering zone and fitted with a separate shutoff valve. The most common types of watering zones are a sunlit front lawn that must be watered long and often; shady areas that need briefer, intermittent watering; and gardens that are watered through sprinklers with high heads.
The so-called pop-up sprinkler heads that you are most likely to use are installed just below the surface of the ground, out of sight--and out of the way of lawn mowers. When the shutoff valve is turned on, water pressure forces an internal piston upward to just above ground level, and the water sprays in a full or partial circle; when the water is turned off, gravity or a spring within the head brings the piston down again. Smaller areas and garden beds can be covered by the simplest type of pop-up, consisting of a fixed piston whose only motion is up and down. And area greater than about 60 feet across must be watered by a more expensive rotary pop-up, which has a rotating piston or spout that shoots out long jets of water.
Designing a system that takes into account all the variable of site and vegetation is a job for an expert. Fortunately, it is also a job that an expert will do for you free of charge. Most distributors and all manufacturers of sprinkler parts will supply you with the blueprint of a system tailored to your home, in exchange for your promise to buy their parts.
To help the designer, you must supply him with certain information--a rough scale map of your house and grounds, together with data on plantings, plumbing system, soil and climate. The designer will have to know where you have grass and where you have flowers or bushes; which areas are sunlit and which shady; whether your soil is sandy, rocky or compact. If you use a public water system, he will need the internal diameter of your water meter in inches (the figure is usually stamped on the meter housing). For a private system he must have the pump discharge pressure and pumping height. For either system he should know the available water pressure in your supply lines. Your distributor will lend you a pressure gauge to get the last figure. Finally, indicate the diameter of the pipe from which you plan to tap water.
The blueprint you receive will indicate the type will indicate they type of sprinkler head to use in each zone, the exact location and settings (for full or partial circles) of the heads, and the layout and diameter of the interconnecting web of plastic pipes.
In the first stage of installation, the water supply is tapped and controls are installed. For manual controls, tap at a sillcock, and for an automatic system, install the controls in the basement and tap water from an inside supply pipe. Then dig the trenches, pitched away from or toward the house; run pipe and install the sprinkler heads. Be sure to test the system before you bury it underground, so that if adjustments are needed, you can make them with least trouble.
