Horticulture

Low Output (Drip) Irrigation

The basic precept of drip irrigation or "low output" irrigation is to reduce water wastage. In a short view, home owners, commercial building, cities, and especially sports activities like golf and sports fields, waste billions of gallons of water every month. The Water Management District has the legal right to enact penalties and to construct water usage rights, and target homeowners first, since there are so MANY homes, and often the homeowners are unaware of how much they actually waste. It is common for an average homeowner to use 3000-5000 gallons of water, often drinking quality water, on their home landscape every week. This is far in excess of what the plants actually need.

Many reliable estimates say that up to 40% of all overhead irrigation water is lost to evaporation. Even a modest 10% estimate is too much to tolerate. We WILL see permanent water restrictions, even if they're not critically needed now. I believe we should conserve our water resources, even if we take take small measures, such as increasing the organic matter in the planting beds, reducing high-nitrogen turf fertilizers, and using ground-level irrigation. Very few plants take up water through their leaves, so why do we continue this dogma of using big splashy water heads to water our landscapes ? The answer is that they are easy to install, and contractors are comfortable with the technology.
We can dramatically reduce disease problems and use far less water at the same time by using drip or low-output irrigation wherever possible. Although this isn't practical for turf areas, it is certainly practical for high-water demand plants like ferns, terrestrial orchids, begonias, and many other plants, especially annual flowers.

Drip irrigation can be used in drought times, even under severe restrictions from the Water Police. There are hundreds of different types of water delivery systems, but the simplest and most durable are heavy duty plastic / poly lines with pre-punched emitters in them, usually at 12 inch intervals. Each emitter will usually emit 1 gallon of water per hour, plenty for an average begonia or fern. Rig one of these lines, available from Home Depot, to a battery operated timer at the hose tap. Set the timer for every other day, for an hour at each water cycle. Lay the drip line in a pattern in which the lines are about a foot apart, whether it is in a big oval or racetrack style pattern or even a concentric circle. You should cover about 3 square feet for each foot of line, therefore a 100 foot roll of tubing will cover about 300 square feet. This works out to a bed about 20 feet by 15 feet. You can use up to 300 feet of tubing for one hose tap outlet. You can also rig the drip line to an existing irrigation head with fittings from Home Depot or a well-stocked irrigation supply house like Melrose Supply. You can also rig a multi-outlet valve to a hose tap and attach several drip lines and timers to one hose tap, with a different schedule for each one.

The best parts of such irrigation is that it's easy to do, you can do it yourself without much trouble or cost, it saves a lot of water, and you can run the lines anytime day or night. Perhaps even better, your neighbors won't know you're doing it ! Cover the lines with mulch to keep the soil moist and the lines cool, and the results will be well worth the effort. One of the problems with low-output irrigation is that with our hard water, the lines get clogged up after a few years. It's easier to replace the lines than to try and clean out the emitters. There are numerous add-on spray nozzles and drip heads which can be punched into these lines, if you need a little extra water for a special plant. It is important to bury fertilizer in holes underneath the drip lines, since there won't be much "rain" available to wash over the fertilizer if it is spread out on the soil.

Once installed, these system work remarkably well, save a ton of water, and allow plants to grow with fewer disease problems, since there is less water on the foliage to foster diseases. Drip systems are compliant with even severe water restrictions, are "green" technology at its best, and cost rather little. Most of the parts can be purchased via on-line sources, or even at well-stocked Home Depot stores. The University Extension Service has good publications on using drip systems, and they can even be rigged effectively to work on hanging plants, mounted plants, and convoluted topography. We should start installing these systems, even on small scales, in almost any garden where automated irrigation is currently installed.

----- Craig Morell

Expert: Craig Morell

Craig Morell is a career Horticulturist in Miami, Florida, and has been involved with tropical plants and horticulture all his life. He has been growing orchids and tropical plants for over 30 years, and has a bachelor's degree in Ornamental Horticulture from the University of Florida. He currently works as a public garden horticulturist in Miami, and founded Landscape Restorations, a horticultural consulting firm. He previously worked for the Boca Raton Resort for 10 years as staff horticulturist and nursery manager, and has worked in plant production nurseries in Miami, as well as head grower in a commercial orchid firm in West Palm Beach. There is even a registered orchid hybrid named for him, Phalaenopis Craig Morell. He writes frequently for plant society journals on horticulture, as well as for a number of local newspapers. He currently lives in South Miami.