Drip Irrigation - A new spin on leaky pipes

Most people were raised to think that leaky pipes were a bad thing, to be fixed as soon as they were discovered. To let that drip, drip, drip continue was not an option…until now. Drip irrigation takes the idea that leaky pipes are bad and stands it on its ear.

Drip irrigation was first developed in Israel where water conservation is a constant priority. In order to eliminate evaporative water loss, the concept of the leaky pipe was married to the reality that plants grow best in soils that are consistently moist. The resulting system dripped water from supply tubes onto the ground at the base of plants at controlled rates. By putting the water directly on the roots several things were accomplished: first, evaporative water losses associated with traditional agricultural irrigation methods were eliminated. Second, by applying very small amounts of water over long periods of time the soil is kept consistently moist soil, which created robust plant health even in semi-arid conditions. Finally, by irrigating just the plants themselves and not the surrounding soil, weed growth was greatly diminished, which in turn enhanced plant health and promoted higher yields.

There are two types of drip irrigation systems. The first is the traditional system that drips water from a metal or plastic water line onto the ground at the base of your plants. A newer twist on this is micro-irrigation. These systems use miniaturized versions of well known irrigation components to water very small areas and individual plants in the most beneficial ways without losing excess water to evaporation.

The two types of drip systems available, traditional drip and micro-irrigation work slightly differently. Traditional drip systems use plastic tubing with drip emitters either pre-installed in the tubing, or installed by the user wherever they make the most sense. The other system, micro-irrigation, is based on traditional drip theory, and can be mixed and matched with traditional drip. The difference lies in the drip heads and where they put the water. Micro-irrigation uses miniaturized versions of traditional irrigation sprayers to deliver the same small volumes of water to the roots and foliage of your plants. While micro-irrigation preserves the benefits of drip irrigation it also greatly extends its usefulness.

All drip systems use the same three major sets of components; the water source components, the distribution components, and the emission components. The water source components connect the drip system to the water supply, whether that is an irrigation riser, or a garden spigot. There are two parts, the filter, which removes particles that could clog the emitters, and the pressure regulator, which maintains the correct pressure for the drip system - typically no more than 25-35 PSI.

The distribution components are the 1/2" and ¼" tubing, fittings and stakes that create the branches of your system. Of these, the tubing requires the most attention when buying. The tubing needs to be flexible and chemically stable so it doesn't leach contamination onto your plants. Some manufacturers use reprocessed polyethylene (PE) which works short- term, but down the road contaminants in the reprocessed plastic tend to make it unstable and unreliable. Use 100% virgin PE for the best long-term results. Vinyl tubing can also be risky. It is very flexible, but vinyl tubing has been shown to leach chlorine into the water passing through it, which can damage your plants. Instead, look for laminated PE tubing. Laminated PE tubing is made of several layers, each with different properties. Together they create a flexible, stable, and long-lasting tubing system.

Drip emitters, micro-sprays, foggers or misters, and in some cases stream jets comprise the emissions components. Drip emitters apply water directly to the ground at a calibrated rate and are recommended for plants spaced 3-4 feet apart. Pressure compensating emitters are available which ensure that you get even water distribution no matter where the emitter is located in your system. This is especially important if you have long runs in your system, or if they are running up or down a slope. Foggers/Misters create a fine spray of water vapor right at a plant's leaves. These are great for hanging plants and orchids. They can also be used for evaporative cooling of patio and deck areas. Micro sprays and steam jets are miniature versions of traditional irrigation heads, except they work at much lower flow rates. These little sprayers are great for watering ground cover areas and shrubs.

The performance of all emitters is graded by the American Society of Agricultural Engineers. You should always look for a Grade A rating. Grade A means the emitter consistently performs to the manufacturer's specifications under all conditions. Any lesser rating means you are not getting the most from your system.

Drip irrigation represents a great advance in irrigation science. Not only is it more efficient than large irrigation systems for watering small spaces and individual plants, it also helps them to grow larger, with fewer weeds to be pulled. Couple that with the simple installation and drip/micro irrigation is one of the best things you can do to your yard and the plants in it. So, while water shortages are getting more common, and regulation and fees more prohibitive, isn't it nice to know there's a system you can use that easily solves these problems, gives better results, and does it easily.