Converting Your Home Irrigation System for Native Plants

Micro-Irrigation Systems

A micro-irrigation system is one that delivers low-volume water just where it is needed. Mulching is an essential component in the overall scheme of things to reduce water needs, and this also serves to hide the irrigation tubes and outlets of a micro--irrigation system. Micro-irrigation can be drip systems, micro-sprinklers, or soaker hoses. If you are enrolled in a rebate program, check your paperwork for any irrigation requirements to satisfy to qualify for the rebate.

Here is a brief summary of the many advantages of a micro-irrigation system:

  • Low-volume water is delivered at the soil level which minimizes water loss due to evaporation from heat and wind.
  • The water is provided close to the roots which is more beneficial to the plant, than wasting a lot of it on the leaves.
  • Keeping water off the leaves minimizes fungal attack of the vegetation.
  • Not watering the areas where there are no plants minimizes wide-spread weed growth.
  • These systems are easy to install and are durable.

Some rebate programs will require you to get rid of your high-volume sprinklers to qualify for the rebate. If you decide to hand-water and are trying to comply with your rebate program, then it is easy to dig around the sprinkler heads, remove the heads and the risers and cap off the end. Make a sketch of your yard and mark the positions of these capped ends. If you change your mind a year later and do want to put in some automatic irrigation, then you will know where to dig to find those capped irrigation outlets.

An Irrigation System Suited for Native Plants

When you replace your lawn with dry-summer adapted native plants, it will no longer be necessary to deploy your overhead sprinkler system. It fact, the essence of what we have been trying to achieve is to be rid of wasteful irrigation methods and water-thirsty plants. Our goal is to establish the native plants in about two summers, and then stop all supplemental water. At this point the plants would have established the root system necessary to survive the next 20 odd years.

Drip irrigation is not a recommended irrigation method for native plants. The contour of the soil wet by a drop emitter resembles a narrow and tall cylinder. A desired profile for horizontal root growth of many native plants is one that resembles a wider and somewhat shorter cylinder. This might seem as though we are contradicting ourselves since we just told you to water deeply. But deep did not mean you sacrifice the width and go twice as deep as the roots. If you are planning to use drip, then place at least four emitters per plant at the drip line, covering the plant on as many sides as possible. Six emitters is even better.

The question you must ask yourself is whether you have the time to do the occasional deep-watering by hand during the establishment period, or whether you would prefer not to hand-water. If the latter, then you are probably going to replace the over-head lawn sprinklers with a micro-irrigation system. If you don't have any irrigation now and want to put one in, then get yourself a good book on installing irrigation systems. Ortho has a good one for example that walks you through the whole process. The rest of this discussion is based on the premise that you do have a system already and you are replacing the sprinklers with a micro-irrigation system like micro-sprinklers or soaker hose.

Capping Off Your Sprinkler System

There are different types of sprinkler heads, stationary and popup, for example. Whatever type of sprinkler head, it is attached to one of the main irrigation distribution pipe (hopefully PVC), that runs horizontally. The attachment can be a rigid riser or a flexible hose. In either case, dig around the sprinkler head and unscrew the sprinker head itself from the riser. You should then be able to cap off the end of the riser which is threaded female, by using a threaded male to pipe PVC connector. Once you have this connector attached using a teflon tape to provide sealing, then you can simply cap off the smooth PVC end by purchasing the appropriately sized cap. Mark the spot on your sketch and refill the hole. You are now ready to move on to the next hole.

Installing a Micro-irrigation System

This article serves as a high-level guide, whose intention is to provide you with enough information on the essential steps required in the process. You should arm yourself with a good book on installing irrigation systems from your local library. If you happen to find one that deals exclusively with micro-irrigation systems, then that is even better.

Follow the steps provided above for capping the sprinkler heads to uncover and unscrew the actual head and put in a male thread to plain PVC connector. The other end of the connector is now ready to be connected to the appropriate end required for either a micro-sprinker or the end of a soaker hose. Buy one set of components and try it out on one of the sprinkler heads. If it works fine, then you can repeat for the others. If you are using a soaker hose, then ensure that you wrap the hose around the drip line of a plant and punch in enough holes to cover the desired watering cyclindrical area around the plant. With either micro-sprinklers or soaker hose, the watering time will probably be about 3-5 hours. Experiment for your soil type to determine the optimum time.

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