OVERSEEDING CAN HELP BEAUTIFY YOUR LAWN

You will need good seed-to-soil contact for the new seed to germinate. Prepare small bare areas for overseeding by raking. Use a light touch, so you break up the soil surface without raking out the existing grass.

You can apply seed to these spots by hand or with a drop spreader. Use the recommended rate for your selected seed when overseeding. Rake the area again with the same light touch after you overseed to improve the seed-to-soil contact.

Overseeding is the practice of adding grass seed to an existing lawn. This may be done only in spots where bare areas show, or over a larger expanse of lawn to improve the density of grass that has become thin.

Overseeding is a common practice in the transition zone, the geographical area between parts of the country where warm-season and cool-season grasses converge.

Overseeding a cool-season grass into an existing warm-season grass lawn will provide color and active growth during the cold- weather-related dormant period of the warm-season grass.

Seed selection should be based on the species and variet- ies of cool-season grass that will establish quickly and then transition out easily when temperatures rise.

Typically, with bare dirt or thinning grass, if 50 percent or more of the existing lawn is in good condition, overseeding can be a workable solution. If more than 50 percent of the area is in poor condition, you will want to consider a new lawn installation.

Bare or thinning problems may be due to damage from heat, drought, disease, weeds, insects, overuse, poor management practices or other factors. It’s best to identify the source of the problem and correct it prior to overseeding. This knowledge will ensure the lawn’s condition doesn’t continue to deteriorate after overseeding. It’s also important to review your long-term maintenance program and make adjustments if needed in how you mow, fertilize, and irrigate your lawn.

You will also want to reduce competition from the existing grass prior to overseeding. Cut the existing lawn to the lowest appropri- ate height for the variety. Do this gradually, if necessary, always following the one-third rule when you mow.

Select the seed varieties that will be compatible with your existing grass, but have specific performance and/or aes- thetic qualities that will improve it. This may be cold, heat or drought tolerance, disease or shade resistance, or simply a deeper shade of green.

For more information on lawn care and helpful “How to” tips, visit The Lawn Institute at http://www.TheLawnInstitute.org. TPI TURF NEWS • NOVEMBER/DECEMBER 2015 9

There are several options for overseeding larger areas: • You can break up the thatch layer with two or three passes with a power rake or vertical mower. Remove the debris after each pass. Apply the seed with a drop or broadcast spreader; then make one more pass with a de- thatching machine to improve the seed-to-soil contact.

• You can use a slit seeder which will cut thin grooves into the soil surface, deposit the seed into the slits, and push the soil down over them.

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You can core aerate in three or four different directions, creating multiple holes in the soil for the seed to fall into. By using core aeration you also reduce compaction and al- low better nutrient, air and water infiltration and penetra- tion. This will improve growing conditions for the existing turfgrass as well as the new seed.

After aerating, apply the seed with a drop or broadcast spread- er. Then cover the area pulling a piece of chain link fencing or an old cocoa mat door mat to break up the plugs of soil you removed and improve seed-to-soil contact.

For additional information on overseeding or core aera- tion talk to the grass specialist at your local garden cen- ter, contact a local sod farmer, visit a university turfgrass extension website, or visit The Lawn Institute website at www.TheLawnInstitute.org.

Modified illustration: Jim Novak