August 21, 2002
Woodbury Bulletin
Betsy Halden

August the perfect month for lawns

When you think of working on your lawn, do you think spring or fall? When the spring snows melt and the leaves start to turn green, many of us are eager to start our outside yard work. Commercial advertising, retailers, and some lawn care companies push spring as the best time to work on lawns. August is actually the best time to invest extra time, money, and effort into improving an existing lawn or starting a new one. The results may be slow to show this year, but work done now will give you a visibly improved lawn next spring.

Here are some of the good things you can do for your lawn in the late summer and early fall.

Fertilization
Labor Day or thereabouts is a good time to fertilize the lawn. With the shorter days and cooler temperatures of late summer and early fall, lawns usually begin to put on a new flush of growth. Root systems, which typically shrink during the summer, increase naturally at this time, and fertilization will help to build healthier turfgrass. Deb Brown, University of Minnesota Extension Horticulturist, tells us that if you fertilize early in the fall, you should also give your lawn a second application later in the fall. Even though the days get cooler, the grass roots stay warm and can absorb the nutrients in the soil. Virtually all lawns will benefit from fertilization.

Core cultivation and overseeding
If your lawn has more than ¾ of an inch of thatch, has compacted soil, or is thin with bare spots, core cultivation, followed by overseeding can improve the soil and the root system of the grass. Overseeding will improve the density and health of the lawn. Core cultivation is accomplished by a machine which takes out small cylindrical plugs of soil, usually about ¾ of and inch in diameter and about 2 inches long, and deposits them on the surface of the lawn. The cores are broken up by a drag mat, and the soil particles settle into the grass. The resulting holes in the ground let in more moisture and oxygen to the roots, which will stimulate turfgrass growth. “Overseeding” is when new grass seed is applied to an existing lawn which has been core cultivated. The new grass will germinate and increase the density of the lawn. These operations are best done when grass is growing well, such is in the late summer or early fall. Adequate rainfall or irrigation is necessary.

Core cultivation machines can be rented from rental centers. Professional lawn care businesses often offer core cultivation services. “Spiking” or “slicing” a lawn is a similar process, but it is generally less effective in reducing soil compaction. The results are usually inferior to core cultivation.

Starting a new lawn
Although we seed most crops in the spring, new lawns are best started during the time of August 15 to September 15. A big reason for this is that crabgrass, the quick germinating weed that can take over a new seedbed, is less problematic at this time. Don’t wait too long to start a new lawn, however. Although perennial ryegrass planted late in the season may still germinate in a week to 10 days, Kentucky bluegrass may need up to three weeks to germinate. Grass seed should be planted early enough to establish roots before low temperatures and deep frost stop all growth.

The University of Minnesota Extension Service offers helpful information on lawn care. The document “Home Lawn Care” includes topics from planting to mowing to disease care. To access it and other materials, go to www.extension.umn.edu and enter “lawn care” in the search box.

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In the August 7 gardening column I gave information about becoming a Washington County Master Gardener. Here is what Woodbury resident Terry Gannon said about being a Master Gardener: “ Being a Master Gardener is an educational opportunity to learn from the very best about up-to-date research at the University of Minnesota. It is also a responsibility to take the information and share it with the public. It is an opportunity to meet a lot of terrific people who are interested in the same topics. The Master Gardener program has always attracted people who really love gardening.”

If you are interested in applying for the Master Gardener program, please call Washington county Extension Service office, 651.430.6803 or FAX your request to 651.430.6801.

Betsy Halden is a resident of Woodbury. University of Minnesota Extension Service and Iowa State University Extension Service materials were consulted in the preparation of this column. You can reach Betsy Halden at eahalden@comcast.net