Lawns: Mid- to late August is a great time to aerate your lawn if the thatch layer is thicker than ½ an inch. Thatch is a build-up of dead stolons. These are above-ground structures that visually resemble stems. They allow a new grass plant to start near the old one. Stolons are the way that grass forms an interconnected sod that makes a nice, dense lawn. However, when they die, if they are too thick, they can impede growth and water uptake. Thatch looks like a layer of dead grass and builds up on top of the soil. Aeration may be needed on sodded lawns that are over seven years old, seeded lawns over 15 years old and lawns that were established on compacted soils. If you have a thick thatch layer, core aeration is recommended about every three years. You can rent a core-aerator or have a lawn care company do the coring for you. The soil cores are a bit messy, especially after a rain, but will break down and dissolve into the ground again — they dissolve faster if there is good moisture. Mowing the lawn will also break up the small cores. About one week after core aerating is ideal for over-seeding as the newly opened holes and exposed soil allow better seed-to-soil contact. So if your lawn is thin, take advantage of the coring and do some over-seeding in late August to early September.
For more information on lawn aeration, visit http://learningstore.uwex.edu/ and type “A3710” into the search box. When the icon for the publication comes up, click on it and then scroll down to the gold box that says “view the publication” to view and/or print it. You can also order a printed copy from the Dane County UW-Extension office at 608-224-3704.