Much of the water applied to lawns and gardens is never absorbed by plants. The greatest waste of water results from applying it too rapidly or too often. Water applied too rapidly is lost as runoff, which may carry polluting fertilizers and pesticides to streams and lakes. Some water evaporates when applied to bare, unmulched soil, or is lost into the air when applied as a spray, especially on hot afternoons.
Apply water infrequently yet thoroughly. In the absence of rain, most trees, shrubs, and ground covers benefit from a thorough monthly watering during the growing season. Saturate to a depth of 8″ to 10″. This watering schedule applied to lawns will create a deep, well-rooted lawn that efficiently uses water stored in the soil. Watering early in the morning prevents mildew diseases and minimizes evaporation.
Your soil type will determine frequency and duration of watering necessary. Clay soils require more frequent, less thorough soaking. Sandy soils won’t hold much water without humus. All landscape needs more watering the first three years of life, and can be put on a less intense schedule after that.
By using the natural characteristics and tendencies of your landscape, you can reduce the required water use and expense. The word xeriscape is often used to describe this landscaping philosophy, describing water-conserving landscaping techniques and practices. This includes the use of native or well-adapted plants, mulching, and efficient irrigation systems.
Use water discriminatingly and efficiently. Create watering zones to accommodate plant groupings, and avoid watering walks, pavement, and walls. In-ground systems that are properly installed, maintained, and monitored allow efficient use of water resource. The water flows under low pressure through emitters, bubblers, or spray heads placed at each plant. Use timers and/or moisture sensors to prevent over-watering. Drip irrigation is also a water saver. Soaker hoses deliver water directly to the base of the plant, reducing moisture loss from evaporation.
If using sprinkler irrigation, make sure heads are properly adjusted to direct the water towards plants, not sidewalks. A sprinkler head should spray large droplets of water instead of a fog or fine mist, which wastes water by evaporation and wind drift.