dead patchy lawn

Asked August 30, 2018, 10:40 AM EDT

This part of my lawn always gets patchy in the summer. It is adjacent to a swimming pool and is fenced with a chain link fence. It gets no foot traffic. The dying part is kind of orangish colored compared to grass that is dying from draught. I am stumped as to what it is. I dug up an approximate 3'X2' section of the dead grass yesterday and only saw 1 white grub and a few small dark colored ones.The grass was totally dead, soil seemed compacted. In the early summer I've seen what looks like spider webs across the grass and sometimes a mushroom, now it is full sun. I have a sprinkler system. Rather old and maybe not the best coverage, It was fertilized in the spring. I've gone through all the possible causes-pests, diseases on line. Thank you. Maggie Merkow

Hennepin County Minnesota

2 Responses

Thank you for the question. There are many possible reasons for brown areas in a lawn. Insect, disease, and lawn care practices are a few possibilities. Turf grass diseases are particularly difficult to identify because the organisms that cause the problems are usually microscopic.
You need to get inches away from grass blades and use a magnifying lens to find the problem and even then, diagnoses can be elusive. Any treatment is based on accurate diagnosis. Check your grass blades carefully at the intersection of healthy and brown grass because that's where you will get the most information. Completely dead grass blades don't provide many clues!
After closely examining your grass blades for evidence of disease you may decide that you don't have one. You have already ruled out grub issues by careful inspection. The other possibilities are abiotic, or non-living causes. Since this problem recurs in this area every year and it's next to the pool, is it possible that some of the pool water splashes out onto the grass? Is the water treated with chemicals? Was construction debris buried here and just a thin layer of topsoil placed over it? Was there a tree there once upon a time? This is kind of detective work! Another possibility is that the area doesn't get enough water and has suffered in our recent weeks of hot, dry weather. I'm sorry I can't tell you exactly what the problem is but maybe you have more ideas now.
Here are a few links that might be helpful to you:
1. Nice list of typical lawn diseases with photos:
2. U of M self-diagnostic program that might be useful:
3. As a last resort, submit a sample to the U of M's plant disease clinic:

Good luck and thank you for contacting Extension.

Thank you for your thoughtful response. I will work on the ideas you suggested. Maggie Merkow