March 14, 2008

Drought and excessive heat damaged many Kentucky lawns this past summer, and continued dry conditions into the fall left homeowners with little chance of repairing them. But the next couple of weeks provide a chance for another try at getting the lawn back into shape.

Lawns with south and west facing slopes and ones on heavy soils sustained the most damage from the hot, dry weather, said A.J. Powell, turf specialist with the University of Kentucky College of Agriculture.

“These areas just couldn’t get re-established in the fall, but it is an option this spring,” he said. “Now until the last of March is a good time to get new grass stands established.”

Powell recommends homeowners use the turf-type tall fescue because it is easier to establish than Kentucky bluegrass. Getting good seed-to-soil contact is also important when reseeding the lawn.

Power seeders or dethatchers, which can be rented, help with that by grooving the soil and giving good contact. Aggressive hand raking works for small areas. Spreading seed over the surface then forcing it into the ground using high pressure watering from a garden hose is another option.

“If you don’t get good seed-to-soil contact, then you won’t get good establishment,” Powell said.

Water newly seeded lawns frequently. Keep the soil surface moist until the seedlings become established. After germination, apply nitrogen to help the young seedlings grow. Generally, nitrogen applications are not recommended for spring, but with new plantings some nitrogen is necessary to establish seedlings.

Fertilizing your established lawn in the spring is not advocated, because it reduces drought and heat tolerance for the impending summer. Spring nitrogen causes excessive top growth, and the root system stops growing. Grass with a poor root system cannot take up as much water and minerals making it less able to withstand drought. Fall fertilization encourages root growth and minimizes top growth.

Spring fertilization also encourages rapid growth of weeds such as crabgrass, bermudagrass, yellow nutsedge and nimblewill. It makes grass more susceptible to leaf spot and warm weather patch diseases.

On established lawns, spring is also time to use pre-emergent weed control to combat crabgrass. However, if a homeowner plans to reseed, they need to skip this, because the weed control will keep the grass seed from germinating.

Spring is also the time to control broadleaf weeds. Spraying actively growing weeds soon after they begin spring growth will yield the best results.

Don't be afraid to mow a new lawn, Powell said. After the turf begins to grow, even if the growth is patchy, mow at the recommended height of 2½ inches for bluegrass and fescue. By mowing early and not letting excessive grass accumulate, the texture will be finer, color will be greener, many upright weeds will be killed, the turf will become denser, and lateral spread will increase.

More information on lawn care is available through county offices of the UK Cooperative Extension Service.

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