Lawn problems such as weeds, disease, and unattractive turf have different appearances from the surface. However, they typically share a common underlying trait of poor soil conditions for rooting and oftentimes a problem thatch layer. Healthy lawns start with healthy roots, which in turn need good soil conditions.

One of the key steps emphasized when establishing lawns is properly preparing the soil, whether seeding or sodding. Oftentimes during the home construction process, original topsoil is removed and replaced by soil with considerable amounts of clay or gravel fill. Soils are commonly compacted, which will drain poorly, contain little air for roots, and will severely slow down root growth. Lawns planted over poor soil conditions like these are of inferior quality and have chronic issues.

In addition to poor rooting, thatch problems often develop with these underlying soil problems. Thatch is a layer of living and dead organic matter, comprised of roots, rhizomes, and stem tissue of grasses, not clippings. Excessive thatch (over one-half inch thick) interferes with water and nutrient uptake and creates favorable conditions for pests and disease. The bulk of grass root systems often end up in thatch rather than soil, further stressing lawns.

If your plans include installing a new lawn, properly preparing the site prior to sodding or seeding is critical. Amend existing soils with quality soil and/or organic matter and always mix into the existing soil on the site. Work the soil to a depth of 4 to 6 inches. Taking the time and effort initially pays big dividends later.

For existing lawns with underlying soil problems, there are ways to correct them. Core aeration is an ideal route to take. Core aerifying machines both make holes to help alleviate compaction and pull up small soil cores to the surface, which are left in place to act like topdressing. This process both degrades and corrects the cause of thatch. Core aerify when soil moisture levels are adequate. Fall and spring are usually optimum times. Consider aerifying as part of a sound lawn care program, especially on sodded lawns.

In addition, topdressing by spreading a thin layer (one-eighth to one-half inch) of compatible quality soil over the lawn surface can also help degrade thatch. Done in conjunction with aerating, this will also help improve problem clay (or sandy) soils.

Thatch can also be torn out with equipment such as power rakes or vertical mowers. Since these processes are destructive to the grass, overseeding is usually required afterwards. Unlike core aerating, thatch removal does not address underlying problem soil, thus, thatch often returns to problem thickness layer shortly afterwards.

Learn more about lawn maintenance in Wisconsin.