Healthy Lawns

June 21, 2003

By Mary Bernard, Master Gardener


Maintaining the quality of your lawn can be a real challenge during the summer months.  Environmental factors such as heat, drought, and wind can seriously affect the health and appearance of turf grasses, especially in inland areas. 

Cool-season grasses such as Kentucky bluegrass and perennial ryegrass are more prone to heat and drought stress than the more tolerant warm-season grasses such as tall fescue and
Bermuda varieties. 

With proper maintenance techniques and regular irrigation (where restrictions do not prevent landscape uses) your lawn can still have a healthy, green appearance during periods of harsh summer weather. 

Here are some tips for maintaining optimum turf quality during the summer:

 

·         Frequent mowing - about once a week during the growing season is recommended.  Grass should be cut often enough so that not more than one-third of the grass blade is removed.  Removing more than this results in 'scalping' which stresses the turf needlessly.

 

·         Keep your lawn at the correct mowing height.  (Tall fescue - 1.5 to 3 inches, Perennial ryegrass and Kentucky bluegrass - 1.5 to 2.5 inches, Bermuda grass - 0.5 to 1.0 inches).  Many experts recommend raising the cutting height during the summer to reduce stress.

 

·         Keep the mower blade sharpened to cut grass cleanly.  A dull mower blade tears the grass blade, exposing it to possible disease infection.  * Leaving grass clippings on your lawn recycles nutrients back into the soil.  A mulching mower finely chops the grass so that it won't smother the turf.

 

·         Fertilize lightly (apply the low-end amount of recommended rates) or postpone fertilization until fall.

 

·         A lawn should be watered when the soil begins to dry out, but before the grass actually wilts.

 

·         Irrigate your lawn infrequently, but deeply enough to moisten the entire root zone.  Deep irrigations encourage grass roots to develop deeper root growth.  Do not water established lawns every day.  Light, frequent irrigation encourages weed seed germination, disease development, shallow rooting, and overall poor turf health, vigor and quality.

 

·         Monitor soil moisture and adjust irrigation schedule according to seasonal need.  Use a soil probe to help determine the moisture in the root zone (the upper six to eight inches of soil).

 

·         Water early in the day - 2am to 8am is best.  Evaporation is minimal during this time, making water use efficiency optimal.  Early evening or night watering is not recommended because wet blades and thatch are highly susceptible to disease development during the cooler nights.

 

·         Water your lawn separately from trees, shrubs, and ground covers, if possible.  * Avoid runoff and piddling as much as possible by cycling irrigations.

 

·         Check your irrigation system regularly and make necessary repairs and adjustments to ensure that sprinklers operate efficiently without wasteful runoff.

 

·         Control weeds.  They compete for water, light, and nutrients.

 

University of California Cooperative Extension Master Gardener Volunteers can provide additional gardening information upon request .Call the San Luis Obispo office at 781-5939 on Mondays and Thursdays from 1 to 5 PM.  You may also call the Paso Robles office at 237-3100 on Wednesdays from 9 AM to 12 PM.  The San Luis Obispo Master Gardeners website is at http://groups.ucanr.org/slomg/.  Questions can be e-mailed to: mgsanluisobispo@ucdavis.edu.