I’ve received several calls from homeowners asking how our wet, waterlogged soils will affect lawns and, especially, newly seeded lawns.
The good news is tall fescue tolerates wet soils. However, tall fescue seeds will not germinate in waterlogged soils. They need oxygen to germinate. The seeds will remain viable in waterlogged soils for several weeks. If soils remain saturated for more than three weeks, seedling germination will be reduced.
Once the seeds have germinated, tall fescue grows well in wet soil conditions, but if there is standing water in the lawn, the fescue will thin out.
Standing water also favors annual weeds. Annual bluegrass is considered a weed by most yard aficionados, and annual bluegrass loves saturated soils. At this point, there are few options for annual bluegrass control. If you have areas of your lawn where water pools, address the water issue first before worrying about the annual bluegrass.
If your lawn is not as thick as you’d like, what are your current options? In the short term, you could add more seed if you have not already applied a preemergence herbicide. This is a temporary fix. Spring-seeded tall fescue rarely lives through the summer heat. However, this is still your best option if you have bare spots and you need to strengthen your existing fescue stand. Another option is more aggressive spring fertilizer. Nitrogen promotes tillering of existing tall fescue. Tillering is when new daughter plants sprout from the crown of established fescue plants.
This tall fescue plant has produced a side shoot, also called a tiller. Fertilizer and good growing conditions encourage tillering. (Credit Seth Nagy)
Excessive rains can also cause fertility problems when nutrients leach in the soil. Leaching is when nutrients move with water through soil below the reach of grass roots. Potash and Sulfur are two nutrients that have the potential to leach out of the root zone.
Potash deficiencies are expressed as increased susceptibility to drought, winter injury, and disease. Soils deficient in potash are also more susceptible to weedy annual grasses.
When Sulfur is deficient, plants have a yellow appearance. It looks similar to a lack of nitrogen, but with a sulfur deficiency, the entire plant will be yellow. With a lack of nitrogen, the new growth is greener than the older leaves.
A soil test will indicate if there is a fertility problem in your soil. A soil test will let you know if there is a problem before your grass tells you there is a problem. Think of it as an early warning system. A soil test also keeps you from over applying nutrients. This can be not only expensive, but counterproductive. For example, applying sulfur when you don’t need it will lower the pH of your soil. Then Lime will be needed to raise soil pH back up.
The wet growing conditions have caused some newly seeded lawns to struggle. However, those planted in September and October, and properly fertilized, are doing well. (credit Seth Nagy)
When in doubt, take a soil test. You can get everything you need to take a soil test from the N.C. Cooperative Extension, Caldwell County Center.
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Seth Nagy is the Caldwell County Extension Director. The N.C. Cooperative Extension, Caldwell County Center, 120 Hospital Ave. #1 in Lenoir, provides access to resources of N.C. State University and N.C. A&T State University through educational programs and publications.
