Getting Your Lawn Ready

FOR IMMEDIATE RELEASE
February 21, 2006

The arrival of April means many people are thinking about overseeding their lawns, said a University of Illinois Extension horticulture educator.

"In general, you do not need to overseed a lawn that is just thinned out due to the winter," said James Schuster. "Instead, consider core aerification--only after several weekly mowings--and/or fertilizing."

Overseeding, he explained, is done to diversify the turf, to help reduce disease problems, or to adjust for change in sunlight.

"For example, a tree has died or been removed," Schuster said. "Therefore, there is more sun so the shade-tolerant fescue may need to be replaced with a more sun-tolerant grass."

Some homeowners want to roll their lawn just because it is lumpy after the winter. Lumpy lawns are more likely to occur in low-maintenance lawns.

"Rather than rolling the lawn, which increases soil compaction and therefore more diseases and insect problems, consider mowing higher or doing a light fertilization," he said. "As the lawn thickens, the lumpiness will be reduced or disappear altogether. If the lawn is lumpy because of soil compaction, core aerify the lawn.

"Overseeding does not reduce lumpy lawns for any length of time if the soil needs fertilization or core aerification. When seeding needs to be done in the spring, it should be done as early in the spring as possible."

Early spring seeding, he pointed out, reduces competition from the weeds. Grass seed germinates at lower soil temperatures than most weed seeds. Most spring weed seeds need warmer soils to not only germinate but also to grow in.

"Spring seeding can be done in landscapes where there is no turf, where there is an erosion problem--additional work must be done to keep seed in place on erosion sites, or where there are large dead patches or large areas that need renovation," he said. "However, if possible try to seed or overseed in the late summer--late August to mid-September.

"Even though grass seeds can germinate in cool soils, grass seed germinates faster in the fall because soils are warm and the air is generally cool."

In addition, he noted, grass seeds do well whether the day is getting longer or shorter.

"There are also fewer weeds that will germinate in the fall because the shortening days and longer nights tend to help minimize germination and growth in many weeds," he said.

Source: James Schuster, Extension Specialist, Pesticide Safety Education - Plant Pathology, schuster@uiuc.edu