Weeds in grass

Asked August 8, 2015, 5:34 PM EDT

Help! Although I pay a lawn service there are lots of weeds and crabgrass in the lawn. I feel like they over fertilize which just makes weeds worse. What is best way to control weeds and still feed the grass? My mower is set on highest setting. Should I lower it? I have kept grass tall all summer to try to choke out the weeds but it isn't helping. I watered during dry spell so the weeds wouldn't take over and grass wouldn't die but don't think it helped much.

Meade County Kentucky

1 Response

The following publication explains weed control in home lawns. http://www2.ca.uky.edu/agc/pubs/AGR/AGR208/AGR208.pdf. Timing of applying a herbicide for weed control is crucial. Most of the weeds we think of as lawn weeds such as dandelions and chickweed are winter annuals that germinate in late summer and fall then flourish in the spring. These weeds are better controlled with the proper herbicide in the fall and/or early spring. If you look at the University of Kentucky publication reference to not all weeds will be controlled by all herbicides. However, most weeds can be controlled by using the right herbicide containing the chemical combination of 2,4-D+dicamba+mecoprop. To control crabgrass, since it is a summer annual where it germinates in the spring and dies after a killing frost, a different herbicide would need to be applied in the spring before April. Herbicides are a good tool when used properly in combination with a good thick healthy stand of grass. Soil testing should be part of a good fertilizer program as well as a possible overseeding practice to ensure a healthy stand of desireable grass. This will help tremendously with weed prevention. Also, regular mowing to where no more than 1/3 of the grass' leaf blade is being cut of at a time will help assure healthier grass. Contact your local Extension Office to learn more about lawn care.