Janesville60.3°

Grass specialist offers advice for post-drought lawn care

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Catherine W. Idzerda
August 24, 2012

— You can think of those big, brown spots on your lawn as silent protests against the cultural imperative toward perfect lawns.

Or you could just reseed those spots and hope next summer won't be so dry.

Now is the perfect time of year to reseed, but where to start? With seed or sod? Soil tests or topsoil?

Doug Soldat, UW Extension turf grass specialist, has the answers for all your turf grass tribulations.

Q: What happened to my lawn?

A: Southern Wisconsin continues to be in "extreme drought" conditions, according to the National Weather Service.

"Many lawns have dead spots like this," Soldat wrote in an email. "Usually, the drought was more locally severe there for some reasonóor combinations of reasonsólike a compacted area, sandy soil, south facing slope, different type of grass than the rest of the lawn or chinch bug infestations."

Q: When should I reseed?

A: Between Aug. 15 and Sept. 15.

"The most important thing is to have cool night time temperatures for healthy grass," Soldat wrote. "It looks like Janesville has lows in the upper 50s and lower 60s in the near future, which is good for growing grass."

That said, Soldat recommends waiting until at least Sept. 1 to start the process.

Kentucky bluegrass has underground stems called rhizomes that can generate new plants. If you have a dead patch of lawn now, it is likely that the size of the dead area will be substantially smaller (or even gone) by September, he said.

In addition, temperature and moisture stress usually is lower in September, when many weeds are no longer germinating.

Homeowners can put in sod anytime before the soil freezes.

Q: Sod or seeds?

A: Seed costs less but requires more care.

Either way, proper soil preparation is key.

Q: That sounds like work. What's required?

A: Kill perennial weeds with a product with glyphosate. Roundup is the most common brand.

Till or loosen the soil. If adding soil to the site, be sure to blend it in. This will improve water movement and root growth.

Old folks probably remember putting down lime to "sweeten" the soil before seeding. In southern Wisconsin, lime is almost never needed. However, a starter fertilizer can help seedlings get established.

If using fertilizer, gently blend it in with a rake.

Follow the instructions on the package regarding the amount of seed.

When seeding, spread seed in both directions. That is, spread seed north to south and then east to west.

Lightly rake the top one-quarter inch of soil for good soil-to-seed contact.

Mulching with clean, weed-free straw helps keep moisture levels steady. You should be able to see about half of the soil's surface after mulching.

Keep the area moist.

Q: What's the best grass?

A: "Kentucky bluegrass is probably the best choice," Soldat wrote. "Perennial ryegrass does poorly in drought and cold temperatures and ice."

Fine fescues haven't done well this summer.

"I do not recommend planting fine fescue in areas that were killed by the drought," Soldat wrote in an Extension publication. "This is a dramatic departure from previous recommendations but is based on things I have seen over the past few weeks."

Fine fescue remains a good choice for heavily shaded sites.

Q: What about a soil test?

A: "Soil testing prior to seeding is a good idea because you can get a customized recommendation for phosphorus, potassium, and lime," Soldat wrote. "However, results take about two weeks, which comes close to the end of the seeding window."

He recommends starting the renovation process now. You can still submit a soil sample and use the results to guide fertilizer applications next year.



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