By Blake Jackson
As fall approaches, Wisconsin homeowners have an ideal opportunity to improve thin or stressed lawns.
Bruce Spangenberg, a Horticulture Outreach Specialist with the UW-Madison Division of Extension, recommends two valuable practices for many lawns: overseeding and core aeration. When performed properly, both can improve lawn health, but each addresses different needs and has limitations.
Overseeding involves adding grass seed to an established lawn to thicken sparse areas. Before spreading seed, homeowners should determine why the lawn has become thin.
Problems such as compacted soil, heavy clay, poor drainage or inadequate soil preparation may prevent overseeding from succeeding. Core aeration can help with some of these conditions, while severe problems may require more extensive lawn renovation.
Other causes of thin grass include excessive shade, selecting grass varieties unsuitable for the location, poor maintenance, weather-related damage, pests and disease.
Once the underlying issue is addressed, choosing a grass seed blend suited to the site is essential. Sun exposure is particularly important when selecting seed.
Good seed-to-soil contact is another major factor in successful overseeding. Homeowners can remove surface debris with hand tools, dethatchers or power rakes before smoothing the soil.
A light layer of quality topsoil can also help. Slit-seeding is another effective option because specialized equipment creates openings and places seed directly against the soil.
Core aeration, meanwhile, is useful for reducing soil compaction, improving surface drainage and helping manage thatch. Spangenberg recommends using a core aerator that removes small plugs of soil and leaves them on the lawn. Fall is a particularly suitable season for this work, provided the soil has enough moisture.
For lawns affected by manageable soil problems, the recommended sequence is to core aerate first, apply a light topdressing and then overseed or slit-seed. Homeowners can rent equipment or hire lawn-care professionals.
Overseeding should ideally be completed by early September so new grass has sufficient time to establish before freezing temperatures arrive.
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Categories: Wisconsin, General