The best way to water your plants is drip irrigation because it minimizes water loss through evaporation, eliminates erosion from overspray and excessive runoff, reduces weed growth, and results in healthy plants and higher yields. Well-designed drip irrigation systems direct the right volume of water exactly where each plant needs it, and you can save up to 70 percent in water use. Drip irrigation can be tailored to just about any garden, landscape or container garden situation.
While we hope for an abundant rainy season, the generally pleasant month of September is an ideal month to undertake an outdoor garden project. And should we have a great winter in rainfall, your system will be ready for spring. Before you purchase any drip irrigation components, assess your needs.
SKETCH OUT EXISTING CONDITIONS
Consider area dimensions, including various elevations; size, type and location of beds, plants and soil types; water source location; best place to run the main line; and your water pressure level.
BASIC DRIP IRRIGATION SYSTEM COMPONENTS
Familiarize yourself with the following components so you can determine the best system for your needs.
On-off valve: For small systems, look for a low-flow shutoff and an antisyphon device. This keeps water in the system from flowing back into your clean water supply.
Filter: City water pipes contain sediments that can clog your system.
Timer: This is essential. Multiprogramming automatic controllers work the best.
Pressure regulator: Unless you plan to use multiple-outlet emitters designed for high-pressure operation, the pressure from your household line will probably blow your drip irrigation system. A regulator will reduce this pressure before it hits the system and will maintain the correct pressure. It’s best to have one pressure regulator for each main line. Pressure regulation is strongly recommended for all installations.
Polyvinyl chloride pipe: PVC pipe is a rigid type of pipe, usually buried a foot below the surface. Risers attach to this pipe and bring water to the surface where it is delivered to the plants through emitters. Buried PVC pipe is especially good for permanent installation and where foot traffic, children’s play or vandalism may break or disconnect a surface system. Extra time is required to bury this type of system.
Polyethylene tubing: This is a flexible plastic pipe commonly installed on the surface and covered with mulch. Emitters connect directly to the main line or to smaller lateral branches. This system is easy to access but may be vulnerable to damage in high activity areas.
Emitter: This lets you choose exactly where you want the water from the main and branch lines to go. Water drips into the soil and plant foliage stays dry, stopping the spread of fungal diseases. Emitters come in many configurations. Purchase emitters according to the flow rate (gallons of water per hour) you want to direct to each plant. This will depend on the type and size of plants and type of soil. Use higher flow emitters in sandy soil and for deep-rooted plants and lower flow emitters in clay soil and for shallow-rooted plants. In most cases, you want to wet at least 60 percent of the root zone.
Misters, minisprays and minisprinklers: These are good for continuous low vegetation (such as ground cover), plants with shallow root systems and vegetation that benefits from overhead water and high humidity (e.g., ferns). These components operate more like conventional sprinklers but run with low pressure, low flow, and lose less water through evaporation. They are especially effective in sandy soils.
Continuous-flow pipe: This type of pipe oozes water into the soil continuously and is best used with a filter and pressure regulator. You don’t need to add emitters, so set-up is easy. The downside of this method is that the holes have a tendency to clog.
Calculate what you’ll need to set up your system: number of emitters, size and amount of pipe, etc. Next, measure the flow from your water source: Turn water on to full flow and let it run into a big bucket for exactly one minute. Measure the volume of water and multiply by 60 to get gallons per hour (gph). That number is the number of emitters you can use in your system.
Maintain your system by checking it regularly for blockages. Repair leaks immediately and flush the lines twice a year.