An important first step in planning a lawn irrigation system is determining what type of soil you have. How often you should water your lawn will depend on the type of soil you have. The two major concerns with any irrigation system are the health of the plants and conserving water.

There are three basic types of soil. The three types are: clay soils, loamy soils and sandy soils. Sandy soils dry out quickly and require frequent watering. You have to be careful you don't water too much at one time with sandy soils. Too much water will drain quickly down through the soil moving too fast for the roots to absorb it, plus the water is wasted. The best approach with sandy soils is to water for a short period of time several times.

Clay soils also benefit from watering over several short periods. Clay soils retain water but absorb it slowly so several short periods allow the water to slowly seep into the soil.

Loamy soils are considered the best soil for almost any plants and if you have loamy soil you are to be envied. Loamy soils easily retain water but they also drain well which lets air get to the roots. These soils can be watered regularly without having to worry about watering in several short bursts.

As an example of how the different soil types handle water 1 inch of water will penetrate sandy soils to 12", loamy soils to 6-8" and clay soils to 4-5".

If you don't know what soil type you have you can send a sample of your soil off to your state's soil analysis lab or cooperative extension service. The lab will determine the soil texture and oftentimes also do a nutrient analysis for you. The nutrient analysis will tell you what nutrients your soil lacks which will help you determine what type of fertilizer to use and how much. There is normally a small fee for this service.

Or you can do your own simple test. Pick up a small hunk of moist soil and try to shape it into a ball. If your soil is clay you will be able to roll it into a ball. With loamy soil it will seem like you can form a ball but it will eventually fall apart. Lastly, if it is sandy soil you won't be able to form any kind of ball.