The best time to water your lawn is in the early morning. The wind and heat are usually less in the morning and the most water will reach your lawn and get soaked in to the ground instead of evaporating. Watering your lawn late in the day or evening will not harm your grass but might increase the chance of disease because your grass may remain wet all night.

Watering your lawn for a longer period of time and letting the soil dry out between watering will encourage the grass roots to grow deeply. Deep rooted grass has a better chance of withstanding a dry spell. Since weeds are usually at the surface of the soil this will prevent the weed seeds from germinating.

Watering during a drought:

Don’t water your lawn during a drought. The grass will naturally turn brown and go into a dormant state. Watering during a drought will not be enough to keep your grass green especially if your town has water restrictions. But it will keep your weeds alive since weeds have shallow roots.

Over watering your lawn:

Watering your lawn too much will keep the top layer of your grass wet and encourage grass to develop weak shallow roots. This could lead to a nitrogen deficiency because excess water will leach out nutrients from the root zone.

Watering grass on a hill:

If you have a trouble growing grass on a hilly slope it is probably do to a lack of water penetration into the soil. The water will run downhill before it can soak in. Increase the frequency of watering your lawn and decrease the length of time you are watering. This way your lawn will have more of an opportunity to soak the water into the soil before it runs downhill. Aerating your lawn to get the soil loose will also help with the absorption of water.