Home Lawn & Gardening Watering Guide

Carlos Pacheco

It is estimate that many gardeners use about twice as much water in their landscapes than is required. As much as 80 percent of the water used around the home during summer is for outside use. The amount of water used can be reduced without creating serious plant problems. During dry summers, local water authorities may cut off water for outside use or only allow watering on certain days. Both measures are necessary and effective means to reduce water consumption and relieve the strain on city water supplies.

Water-efficient landscaping does not mean using only desert plants. It means making an existing landscape or garden more water efficient or developing a new site with low water needs.

When to water is the key to water conservation

Water will be absorbed with less evaporation if you irrigate during the cooler parts of the day. Early morning from 6 to 8 a.m. is ideal because during this time the water pressure is highest, disruption of the water pattern from wind is low, and leaves will dry quickly. Evening watering also is fairly efficient, but plants that are susceptible to leaf disease are more likely to be infected if leaves stay wet for too long. The least efficient watering time is during the heat of the day when evaporation is rapid.

Selecting the irrigation for the right job

Automatic irrigation systems with pop-up sprinklers are often associated with excessive irrigation. This is not necessarily true, since properly designed and operated systems supply water uniformly over an entire area without wasted runoff.

Where irrigation is required, efficient water use is extremely important. Efficient irrigation systems can save a lot of water. Trickle or drip irrigation are the most water-efficient systems. Overhead sprinkling generally is less efficient than watering at the soil surface or within the soil. During hot weather, considerable water is lost to evaporation when overhead sprinkling is used.

Ideally, you want to apply enough water to have the top 6 inches moist but not soggy wet. If water starts to run off before areas are thoroughly soaked, stop the sprinklers or hoses, and do not start watering again until soil is capable of absorbing additional water. Efficiency is lost rapidly when water runs off the surface.

Quick facts on watering:

• Lawns and plants may require as much as 1 to 1-1/2 inches of water per week from irrigation or rainfall during summer to remain green and actively growing.
• During extended periods of summer drought, dormant lawns (browned-out leaves) containing Kentucky Bluegrass, Tall Fescue or perennial Ryegrass should receive 1-1/2 inches of irrigation every two weeks to maintain hydrated grass crowns and allow for full lawn recovery when more favorable moisture and temperature return in the fall.
• It is better to water for a longer period of time (as much water as soil is capable of absorbing) and less watering periods.
• Root depth is closely related to the watering depth.
• Deeper roots draw moisture from a larger volume of soil and therefore require less supplemental irrigation.
• Taller grass provides shading of the soil surface and reduces lethal temperatures near the base of grass plants.
• Lawns mowed weekly at a taller mowing height are less likely to be scalped. Scalped lawns lose density and have shallow root systems.

How to conserve water with any lawn:

• Develop a deep root lawn because deeper roots draw moisture from a larger volume of soil, they require less irrigation. Any grass management technique that produces deeper roots will improve lawn performance under dry conditions.
• Mowing practices; taller grass has deeper roots and shades the soil surface. Mow once a week to avoid scalping your lawn. Lawns should maintain a minimal height of 2 inches to avoid drying out and heating up quickly, develop shallow roots, and consequently decline rapidly in the summer.
• Feeding your lawn; in general, use 2 to 4 pounds of nitrogen per 1,000 square feet per year on cool-season grasses such as Kentucky Bluegrass and Tall Fescue. Fertilize primarily in the spring, early summer and late fall.