Archive for Thursday, March 6, 2008

Season begins for year-long lawn strategy

March 6, 2008

While it may not seem like it, we're getting far enough into spring that I'd like to highlight some basic steps in caring for cool-season lawns and when they should take place.

Cool-season grasses that are commonly used are Kentucky bluegrass and tall fescue. Right now (March) is a good time to do spot-treatment of broadleaf weeds in lawns. Pick a day above 50 degrees to do this for best results. Just keep in mind that rain or irrigation within 24 hours after the herbicide application can reduce the spray's effectiveness.

April is the time to apply crabgrass preventer. Crabgrass preventer must be watered into the soil to be effective. Something to remember is that a thick, healthy lawn is the best natural weed control you can have, so spraying is not always needed.

In May, fertilize with a slow-release fertilizer, especially if you water your lawn, or it gets enough rain to keep it from going dormant in the hot summer months. May is also a good time to treat for broadleaf weeds again. If you use a combination weed killer and fertilizer, watering it immediately will reduce the effectiveness of the herbicide. The fertilizer, however, needs to be watered in soon. The best thing to do is to wait and water in 24 hours.

June is a good time to apply another round of crabgrass preventer, but remember to water it in. If you used Dimension (dithiopyr) or Barricade (prodiamine) during your April application, you won't need to add more in June because these two chemicals should provide prevention for the entire season if used correctly.

July is the time to treat for grubs if you've had problems with them in the past. Use products that contain "Merit" or "Mach II" during early July for grub control. These chemicals work to prevent grubs and must be watered in to work effectively. In late July and August, you may see grub damage, but it is too late to used the aforementioned grub controls. This time you'll need to use a fast-acting grub control that contains "Dylox." You should be able to find this at your local garden store or hardware store. This chemical will need to be watered in within 24 hours for maximum effectiveness, like so many of the other chemicals I've mentioned.

September is the crucial period for fertilizing cool-season lawns. Put on nitrogen, and whatever other nutrients your lawn needs, and be sure to water them in.

November is the last month of the year we have to extensively care for the yard. Just like you would clean up your mower or tiller before you put it away for the winter, your yard needs some care before it is "put away" for winter. November is the time to put on the last treatment of fertilizer for the year. The fertilizer is taken up by the roots but isn't used until spring when it helps the grass green up sooner. Like before, the fertilizer needs to be watered in. November is also the time to treat for broadleaf weeds one last time before winter. Like in March, find a day above 50 degrees and do your spraying, but avoid watering for 24 hours after application. Always make sure to follow the directions on the label of whatever you're applying to your lawn.

I hope this information helps you have a nice looking lawn this year. You can contact me for questions at the Leavenworth County Extension Office on the corner of Hughes and Eisenhower roads in Leavenworth, or call (913) 250-2300. I can also be reached via email at


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