If you already have a sprinkler system, it is often possible to convert everything but lawn areas to micro-irrigation without digging or removing pipes — just buy a converter or retrofit kit. These kits allow you to convert a single spray head to single or multiple drip watering devices. However, entire circuits must be converted. It is not possible to have a circuit that contains both high-pressure sprinklers and low-pressure micro-irrigation.
First turn off the water at the main sprinkler shutoff valve and unscrew the old sprinkler head to reveal the riser. Turn on the circuit to flush out any sediment. Install on the riser the adapter for the converter kit you have chosen, plus the converter itself.
Single-outlet emission devices permit you to convert one sprinkler head to a single micro-irrigation device. Multi-outlet emission devices allow you to add, for each original sprinkler head, two or more outlets.
Lengths of 1/4-inch poly tubing can be added to direct the drip-irrigation flow in any direction. If all outlets are not needed immediately (as is often the case), don’t remove the plugs from the unneeded ones; keep them for future use. For exact installation details, follow the manufacturer’s instructions.
In the case of pop-up sprinklers where the riser is underground beneath the housing and hard to reach, it is often easier to use the housing as an adapter than to remove it. Many suppliers offer a retrofit kit designed for this purpose. These kits are not universal, however. Make sure that the kit you choose is adapted to the sprinkler line. To install, remove the nozzle mechanism of the pop-up sprinkler from the housing and insert the retrofit kit — a pressure regulator, filter, and section of threaded riser. Attach the micro-irrigation device of your choice to the top of the riser.
The conversion process will leave you with a number of unused spray heads that must be capped. To do so, add a 1/2-inch threaded cap to each unused riser. Special caps are also available to cover unused pop-up sprinkler housings.