Proper Irrigation for Turfgrass
The Right Way to Water Your Lawn
Water is a key component of any beautiful lawn or garden, but not all plants are the same. Different plants have different watering needs and the amount of water your yard needs will depend on what is growing there, your soil type, and recent weather conditions. Overwatering a lawn or garden can result in increased disease problems, while not watering enough can stress plants, leaving them open to attack by insects. This article outlines proper watering and irrigation practices for lawns and is the first in a three-part series on water-wise practices for your lawn and garden.
Test Your Application Rate
Lawn watering recommendations are given in terms of inches of water to apply, yet when most people think about lawn irrigation they think in terms of how many minutes their system needs to run. Irrigation systems vary in the amount of water they apply .To determine how long your system needs to run to apply a specific amount of water you will need to check your application rate.
To check your system’s application rate, randomly place three to four rain gauges or straight-sided tuna or cat food cans within each of your lawn’s irrigation zones and run your system for a typical irrigation cycle. The amount of water in the cans at the end of this cycle will let you know how much water is getting to each zone. You can then determine if certain zones are receiving too much or not enough water and if you need to adjust your sprinkler heads, as well as if you need to increase or decrease your irrigation time to apply the right amount of water.
How Much to Water
While the general recommendation for watering lawns during summer is to apply a total of one inch of water per week if it does not rain, there is no “one size fits all” model for watering a lawn. How much and how often your lawn will need to be watered depends on how established the turf is, your soil type, and natural rainfall. If your system does not already have one, be sure to install a rain sensor that will automatically shut off your system when rainfall has recently occurred. This will reduce unnecessary watering and reduce the risk of serious turfgrass diseases like large patch infecting your lawn.
Watering New Sod
As a general guideline, sod installed in the summer should be watered two to four times a day for 15 to 20 minutes during the first couple of weeks. This will ensure the sod and first few inches of soil stay moist but not soggy. After a week or two, check to see if new roots are growing down into the soil. If so, cut back to watering once a day in sandy soils, or every other day in clay soils, for the next week or two. Check the soil often and adjust your watering to avoid saturating the sod as this will prevent new turf from establishing a healthy root system. After a month you should be able to go to normal watering.
Watering Established Lawns
To conserve water in established lawns, consider watering on an “as needed” basis rather than a set schedule. In the heat of summer look for signs of wilting or plant stress. If footprints or mower tracks remain at least one half hour after traffic, you should water.
When you do water, aim to moisten at least the top six to eight inches of soil, where the majority of the lawn’s root system is found. In sandy soils this will require one-third to one-half inch of water, while in clay soils you will need to apply one-half to three-fourths an inch of water to moisten the root zone. It is better to water deeply and less frequently to encourage deep root growth and a healthier stand of turf.
When to Water
The best time to water your lawn is in the early morning hours, between 3 a.m. and 7 a.m., when temperatures are cooler and the evaporation rate is low. Avoid watering between 9 p.m. and 1 a.m. or after 8 a.m. Watering at these times can extend the leaf wetness period created by dew, which can increase disease problems such as gray leaf spot.
To learn more about caring for your lawn visit the NC Extension TurfFiles website, http://www.turffiles.ncsu.edu/. For lawn and garden advice, visit http://ces.ncsu.edu, where you can post your questions via the ‘Ask an Expert’ link, or find your local Extension office. Make a pledge to save water, by taking the 40 gallon challenge at http://www.40gallonchallenge.org/.