Watering the Lawn 

It is necessary to water lawns that will be kept green throughout the summer.  Starting a watering program, especially if the lawn is fertilized, and then stopping, can be more harmful than allowing the lawn to go dormant at the beginning of  a dry spell. Do not start watering if the watering can not be kept up through the entire mowing season. 

Early morning watering is preferred  ( 3-5 am). This provides water to the lawn during the quietest part of the day before the heat of the day and little water evaporates due to high temperatures. 

Watering may be done during the heat of the day but much of it will evaporate due to high temperatures and wind  (up to 90%). Wind may affect water distribution during mid-day waterings. 

Lawns require 1- to 1 1/2 inches of water per week. This is about 640 gallons per 1000 square feet. A garden hose would normally take about 2 hours to apply an inch of water to 1000 square feet. Sandy soils will require two waterings per week to maintain adequate moisture levels. 

Apply the water before the lawn actually goes dormant and when it begins to wilt. Wilted lawn grasses will have a bluish cast and footprints will persist for some time. Once wilting occurs, begin watering. 

How the water is applied is important. Sprinklers should apply the water evenly over the entire area. To determine how long it takes a sprinkler to apply an inch of water, put cans at different spots in the sprinkler pattern. Turn on the water and keep track of the time it takes the sprinkler to put an inch of water in all the cans. 

Apply the water only as fast as the soil can absorb it. Heavy clay soils absorb water slowly. After the surface layer is wet, the water may run off rather than soak into the soil. 

Any rainfall must be considered as part of the inch of water for the week. Summer rain often comes in the form of thunderstorms during which a lot of water falls in a very short time. Since much of this water runs off, it is not captured by the soil for plants to use. Do not consider short, intense rainstorms as providing a significant amount of water for lawn growth. 

Homeowners with underground sprinkler systems should set the system to deliver that inch of water per week over the lawn in two applications.  In order to do this you will have to know what the precipitation rate of each zone on your system,  You might refer to the system installer for this info. 

Be sure to give your lawn adequate amounts of water with each watering.  Failure to do this will result in shallow root growth and as a result your lawn will be more vulnerable to stress. 
 
Making The Most Of Automatic Sprinklers: 

Most of us know how important water is for keeping our lawns and landscapes healthy and  green. Without water our grass and plants cant survive. Automatic irrigation systems are great.  They eliminate hose pulling and can do your watering chores anytime, even when you’re asleep 
or out of town. But even with the most sophisticated sprinklers, you could still be sending money down the drain if its not used right. 

Getting coverage and depth is the first step. 

Your lawn needs 1-2 inches of water a week. That is about 600-900 gallons per 1,000 square feet of  grass. That’s a lot of water and you don’t want to waste any of it. The first step is to know when (and  how) to turn your system off. That’s right. We see sprinklers going full blast in the middle of rainstorms 
sometimes and wonder if the folks are asleep or if they don’t have a master  switch for their system. You need to know how much rainfall you’re getting to know when your system needs to run and when it  can be turned off for awhile. Keeping in mind how much water your lawn needs, setting the timers on  your system will determine how deeply you are watering. 

A big temptation with automatic systems is to water the lawn for a short time  every day or two. This results in shallow watering and shallow, weak roots. 

It's also very important to be sure that all of the lawn is getting watered. Each type of sprinkler head  has a different pattern and flow rate. If your system is properly designed, it is divided into zones that cover all of the turf and planting beds on your property. 

Maintaining In-Ground Sprinkler Systems 

Most in-ground sprinkler systems today are efficient and precise. But regular, minor adjustments to these automated systems can lead to major improvements in how well they work:   Check sprinkler heads periodically to make sure none have been jostled and they are still aimed in  the right directions. Be sure sprinklers have an even spray pattern and that leaves or other debri s aren’t blocking the  spray as your landscape grows. 
Keep an eye out for any damaged sprinkler heads or poor filters. 
Make sure your timer is adjusted correctly for the time of season. 
Follow manufacturers instructions for winterizing your system each year. For  systems in our climate, this  means blowing out pipes so water that can freeze doesn’t do any damage.    Consider drip systems for deep roots. They deliver water very slowly so it can penetrate.