How to Install a Sprinkler System
Installing an underground sprinkler system requires some work, but it makes watering the yard as simple as flipping a switch.
Installing a soaker hose irrigation system makes watering the gardens, wherever they are located, as easy as setting a timer. Soaker hoses deliver water right to the roots of the plants where it is quickly absorbed. This method also keeps water off the leaves, which can lead to disease and pest problems.
Hire an irrigation specialist to run a water line from the main water source at the house out to the yard. He or she will use a mechanical trencher to dig a deep furrow to the required depth for the geographic zone. This supply line will terminate in a valve box, which is buried just below grade.
This master valve controls all the water going to the garden. The valve allows you to shut off the water in winter to keep the supply lines from freezing. To install the valve, first cement a 3" piece of 3/4" PVC pipe to the main supply line. Paying special attention to the water flow direction, connect the shut-off valve to the PVC pipe.
Depending on one’s location, the installation of a backflow preventer may be required by local code.
Irrigation systems have control valves for each zone. This plan calls for two main zones, the left and right sides of the garden. Cement a 3" piece of 3/4" PVC pipe to the open end of the main shut-off valve. Attach a two-zone manifold with control valves. These valves open and close electronically based on signals from the programmable timer.
Connect two PVC pipe supply lines to the control valves. These lines should be long enough to reach the far end of the gardens. Run the lines down a trench to the garden. Using a saw, cut the main supply lines in front of each garden bed and cement in place a "T". From each “T”, run a piece of PVC pipe long enough to reach the outer edge of the garden bed.
Have the irrigation contractor dig the trench for these lines along with the one dug earlier for the main supply line.
Having spigots at each bed allows the gardener to control which beds get watered when the system comes on. This way, if a bed is empty it won't receive water. At the end of each garden supply line, attach a 90-degree PVC piece so that it points skyward. Cement lengths of sunlight-rated PVC to the elbow pieces, bringing the lines up to the height of the beds. At the end of each line attach a spigot connection.
Attach one end of a standard 25' soaker hose to each garden bed spigot. Make sure the other end is capped off. Arrange the soaker hoses around the base of the plants in the garden beds.
Cover all of the trenches with dirt and tamp them down. At the original source of the water line, attach the programmable timer. This controls when the zone valves open and close, sending water out to the soaker hoses at each bed.