Nasty Grasses

Asked April 15, 2020, 12:50 PM EDT

Hello! Each year, despite my best efforts, the quality of my lawn declines. The “good grass” that was present throughout is being replaced by less desirable species (please see attached). My questions are these: 1) what are most likely causes for the success of the less desirable grasses?; 2) how do I prevent the situation from deteriorating further?; and, 3) how can I help my lawn recover? Many thanks in advance for your good thoughts! Tom

Butler County Pennsylvania

3 Responses

The best thing you can do is to get a soil analysis done. You can download a form and send in a sample to Penn State soil lab, https://agsci.psu.edu/aasl/soil-testing/fertility.
After you submit your soil sample following the instructions online, you will receive a report in the mail. Contact your local county extension office if you have questions about the results.

Usually when weeds start to take over, it's a sign that your lawn's pH is too low. But unless you do a soil test to find out your current pH, you can't know how much lime to add. It will also tell you if your lawn is nutrient deficient and give recommendations for fertilizer. It's the best $9 you can spend.


Thanks, I will do that.


After I correct the pH and nutrient issues, how do replace the unwanted grasses. I have been thinking about applying a herbicide and then replanting in the fall.

Also, can you tell from the photos what types of grasses are invading?

Thanks again!


When you get the pH corrected, what I would do is over seed the area. You can certainly use an herbicide, but there are many things to consider; Pets, beneficial insects, kids, grandkids, etc. It is hard to tell from the pictures what the weeds are. There are probably several. Weeds tend to grow best in more acidic conditions, so get your pH fixed and the lawn grass will start to out grow the weeds.