Turfgrass in Minnesota is dominated by cool season grasses including Kentucky bluegrass, perennial ryegrass, tall Fescue, fine fescue, and some less common varieties. A significant benefit of turf is that it is relatively care-free, especially in situations where it can be kept healthy.  However, in less-than-ideal situations, problems can occur. In this post, a few common problems and solutions are explored.

Annual Grass Weeds in Turf

An annual grass is a grass plant that only survives for one season and dies over winter. It seeds down each year and a new crop of seedlings emerge the following spring. Crabgrass is the most common annual grass and is typically found in areas where the turf is either stressed or thinning. These areas often include the turf adjacent to streets, sidewalks or driveways where grass is thin due to winter dieback or heat stress from the hard surfaces.

Crabgrass can be treated using both pre-emergent and post-emergent herbicide. Since crabgrass tends to be localized, seldom does one need to treat the whole lawn. Pre-emergent herbicide needs to be applied before the crabgrass seeds germinate in the spring. Crabgrass germination occurs when soil temperatures are around 55 degrees. The actual date the soil reaches these temperatures vary from year to year depending on the spring season. Unlike pre-emergent herbicides, post-emergent products will kill the crabgrass after the plants have emerged are treated. There are also products that serve the dual purpose of both pre-emergents and post-emergents.

Broadleaf Weeds

Broadleaf weeds are another common turfgrass pest. These weeds are typically a perennial weed that overwinter and return the next season, this means that they are best treated when they are actively growing and not during the dormant season. As with crabgrass, healthy lawns are less susceptible to broadleaf weeds. A few common examples of broadleaves found in Minnesota are clover, dandelion, birds foot trefoil, prostrate spurge, common purslane, chick weed and creeping charlie.

Most broadleaf weeds can be treated in the same way, with the possible exception of creeping charlie. One common method is to apply a broadleaf herbicide along with an application of lawn fertilizer, or it can be applied as a separate liquid application. Creeping charlie, however is more challenging and may only be effectively treated with herbicide that contains dicamba. A garden center or extension agency can provide the best plans for treating creeping charlie.

Grass Clippings

A common misconception around grass clippings is that leaving them on the turf after mowing is a bad thing. If the turf is mowed regularly and clippings are evenly distributed on the turf, they do not contribute to thatch build up. Leaving the clippings actually provides some benefit. For example, grass clippings reduce the amount of fertilizer needed because they are a source of nitrogen for the lawn. Grass clippings should never be disposed of in the garbage, leaving the clippings on the lawn prevents the homeowner from needing to figure out a way to compost them.

Winter Salt

Salt from the winter season can be a problem in turf. Excess salt runoff from hard surfaces can “burn” as a result of dehydration. Although a homeowner can’t control the salting done by a municipality, they do have control of salting on driveways and sidewalks. Determining the amount of salt applied to surfaces can be challenging. Treating the entire surface can be excessive because salt may be applied to dry areas. At the same time, it is desirable to treat icy places where there is a chance for someone to fall and injure themselves. Best practice is to treat only icy areas to minimize salt runoff that can adversely affect the turf and other plants.

Drought

In non-irrigated turf during hot, dry parts of summer, turf may become stressed from lack of water and excessive heat. The turf may go dormant and look dead. Dormancy caused by heat and lack of water is typically not a permanent problem. Cooling weather and more plentiful rainfall will cause the turf to come out of its dormancy and turn green again.

There are several other problems that can occur in Minnesota turfgrass that are not listed here, and most of those problems are treatable. The best practice is to keep turf healthy and well-maintained, which will reduce the likelihood problems. Cool season grasses here in Minnesota are strong and resilient, much like the residents need to be for changing weather and harsh winters! Happy mowing!

Jeff Farrington | Account Manager
Posted 4/14/2021