In some places it would be difficult to grow a decent lawn without irrigation. Due to conservation and water shortages, some gardeners practice Xeriscaping, which is using plants with low water requirements.
ON THE HOME FRONT
In western Pennsylvania, we're fortunate to have regular rainfall during an average year, even though extended wet or dry periods can occur during the summer months. Pittsburgh is doubly fortunate to receive ample rainfall, plus enjoy a steady supply of water from the three rivers. While on the other hand, Philadelphia and the southeastern part of Pennsylvania have suffered some severe summer droughts over the past couple decades.
Clean water is a valuable commodity and prices around the country are reflecting that fact more each year. To be good stewards of this resource, we must not waste, pollute or neglect our future water supplies.
With lawn irrigation systems, the main concern should be not wasting water. By adjusting how often one waters, and at what time of day, the overall situation can be at its best.
WATER EARLY IN THE DAY
By setting irrigation systems to run early in the morning (4:00am to 6:00am) water use can be maximized by preventing the evaporation that's common with irrigation during the heat of the day. Early morning watering is also recommended when it comes to lawn diseases. Evening irrigation can extend the wet period of grass blades and thereby favoring lawn disease development.
Lawns and ornamental plants require approximately one inch of water per week during the growing season. During periods when rainfall is less than this amount, it may be necessary to provide an equivalent amount to keep lawns and plants looking their best.
One thorough watering per week is more beneficial to lawns and plants than several light waterings. Light waterings promote shallow roots, ultimately making plants more vulnerable to drought stress.
ALLOW WATER TO SOAK IN
To prevent water from running off the soil surface, consider setting your sprinkler system to cycle two or three times on the same morning, allowing time in-between cycles for water to soak into the soil.
Add an override device that deactivates the sprinkler system if there's been recent rainfall. Most devices are simply small cups that hold rainwater, and once the rainwater evaporates the system is reactivated.
Generally speaking, the more sprinkler zones the better. Chances are you won't want to water shrub beds as often as you would a lawn area. Or you may wish to water annual flower beds more often than anything else, especially right after planting new flowers. Therefore it's best to have these areas set-up on different zones so you can water one type of area without watering another.
MORE HEADS THE BETTER
The most complete irrigation coverage is accomplished by using more heads. Every section of your lawn should be irrigated by at least two heads creating overlap. In other words, the water spray from one head should reach all the way to another sprinkler head and visa versa. This sort of overlap helps prevent gaps in irrigation coverage. Too few heads in a shrub bed can lead to missed areas as well, especially as shrubs grow taller and wider.
It's important to deactivate your irrigation system for winter by shutting off the irrigation system's water supply, turning off the controller and blowing out the irrigation pipes with compressed air. Failure to do so could lead to burst pipes requiring expensive repairs.
In early Spring of the year an irrigation system needs to be reactivated by turning on the water supply, activating the controller and then ensuring the entire system is operating properly.