Lush green lawns are simply gorgeous-but it can take plenty of work to achieve that stunning emerald look. Watering your lawn correctly is absolutely vital to keeping your lawn healthy and green in any climate. Proper watering of your lawn can even help preserve water, as you'll be using it more efficiently, with less waste.

When and How to Water

You don't necessarily need to start watering your lawn as soon as the first few warm summer days appear. You'll actually achieve a healthier lawn, with a more extensive and deep root system, if you hold off watering until your lawn begins to enter a mild state of drought. When your lawn begins to enter this state, the grass will turn a darker shade of green, and footprints made when you walk across the lawn will remain imprinted, instead of the blades quickly bouncing back up.

If you're able to, watering your lawn early in the day is best. Midday watering is inefficient and may be detrimental to your lawn, as moisture will evaporate quickly at this time. Watering in the evening can help cultivate lawn diseases, as the grass will remain damp for longer periods. However, if you live in a very hot climate, watering during the evening is preferable, as less moisture will be lost due to evaporation, and temperatures will not be cold enough to prevent grass blades drying completely overnight.

One of thee most important points in watering your lawn is ensuring that you maintain an even distribution of water over the entire lawn, and that no spot is either missed or flooded with excess water.

The best way to achieve this objective is with a sprinkler system, rather than with a hose. To ensure your system is providing even coverage over your lawn, place some empty cans or other straight-sided containers at various spots over the lawn, and then check how much water each contains after a watering session.

How Much Water?

Thorough, less frequent watering is much more efficient-and healthy for your lawn-than frequent, light watering. A good, heavy watering that penetrates deep into the soil helps to promote a healthy root system, and also discourages the growth of weeds.

In normal conditions, grasses need between three quarters of an inch and one full inch of water per week to maintain that rich green color, and to keep the lawn healthy and actively growing, as well as attractive. In very hot climates, more frequent watering may be needed. Check your lawn for blade 'bounce' to ensure your lawn receives enough water.

Remember that this requirement includes both precipitation (rain) and watering. If you receive an inch of rainfall in any given week, you can hold off watering until it's needed. In addition, it's important to realize that this one inch isn't an absolute requirement-your lawn won't sicken and die if it doesn't get an inch every week, but too much water in a short time can be harmful. If, for example, you know rain is expected very soon, you can safely hold off watering until after the rain arrives.

How Long?

Each watering of your lawn should provide plenty of water for the active root zone of the grass. The length of time this takes depends on the type of watering system you use, and the type of soil you have. In general, most types of grass need to be soaked to a depth of eight to twelve inches. Some grasses, such as bluegrass, need to be soaked to a depth of six to eight inches.

To calculate how long you'll need to run your sprinkler system to achieve the right depth, do the following:

1. Run your sprinkler system for fifteen minutes.

2. After 24 hours, drive a screwdriver or other implement into the earth to check how deep the water penetrated. You'll be able to drive the implement easily through moist soil, but once you hit dry soil it will become difficult.

3. Divide 120 by the depth of moist soil you determined in step 2. If the water soaked in to a depth of three inches, for example, you'll end up with a figure of 40 minutes. That means it will take two hours for the lawn to be soaked to a depth of nine inches, and two hours and forty minutes to get soaked to a depth of twelve inches.

Water Conservation Tips

• If you live in a climate that routinely achieves very high temperatures during the summer, consider letting your lawn go dormant as an alternative to watering.

• Purchase a rain gauge so that you can determine how much rain your lawn receives, and avoid over-watering.

• Aerate your lawn to allow the grass to use water more efficiently.