MUDDY SPOTS THROUGHOUT FRONT LAWN

Asked March 29, 2019, 3:25 PM EDT

Dear Sirs: Late last summer/early fall, my front lawn deteriorated into a patchwork of muddy brown spots. I think it has to do with too much moisture AKA rain, but I don't know what the problem is or what to do to fix it. Please advise. See photo(s) attached. Thank you so much. Yours truly, Mr. Lynne Tiegs

Scott County Minnesota

5 Responses

Mr. Tiegs - Thank you for reaching out to the Ask an Expert/Master Gardeners with your question! It sounds like you have some muddy brown spots on your lawn and are wondering what the problem is and how to fix it. From your pictures and description, it looks like those are patches of grass that are bogged down with too much moisture and/or that the area is poorly drained. I cannot be sure of the cause without a soil test and a look at the thatch or root system. Start with a home soil test from the University of Minnesota (http://soiltest.cfans.umn.edu) and go from there. Options may include amendments to the soil, improving drainage in your lawn, and/or aerating the lawn to promote better moisture penetration and lessen compaction. This site has more details on how to aerate: https://extension.umn.edu/lawncare/how-control-thatch-your-lawn. Though it sounds like the area has not flooded, these tips on repairing a flooded lawn may be helpful, especially the last paragraph on ponding: https://extension.umn.edu/lawn-care/repairing-flooded-lawns Good luck! Amy

Dear Amy, Thank you for your prompt response to my question. I will mail a composite soil sample the U of M Soil Testing Laboratory this afternoon (Thursday, April 4.) Perhaps it was too much to hope that you could tell me which fungus has invaded my front yard and the best means of treating it. My front yard is basically a mostly flat but slightly hilly piece of land draining to the north and east, wherein lies a prairie ( I planted a small, yard-size prairie there about 6 years ago.) Note, my neighbor to the south appears to have the same problem with his grass/soil. I believe both our yards have adequate drainage. Hopefully we will communicate again once I receive the result of the soil test. If there is anything else I need to know or do, please contact me. Best regards, Mr. Lynne Tiegs

Dear Amy,
I have received the SOIL TEST REPORT from the U of M Soil Testing Laboratory: pH 7.3, ppm P = 52, ppm K = 175. Interpretation: phosphorus = very high, potassium = high, pH = somewhat alkaline, soluble salts = 0. Their recommendation is to apply a fertilizer in the ratio of 33-0-0---at one time, late in summer. Plz interpret these results for me. Is my front lawn covered with brown spots because of too much phosphorus and too much potassium? Is the pH of my lawn too high...and causing brown spots? Or is my lawn possibly suffering from a fungus, which the soil test didn't comment on? If so, which fungus and what to do? RSVP Mr. Lynne Tiegs

Thank you for the question. I have read the thread between you and Amy about your concerns. First, I'll address your soil test concerns, then, the brown spots. Unfortunately, there is no clear answer to your disease question.

A pH of 7.3 is not a cause for concern. Turf grass is able to get the nutrients it needs when soil pH is between 6.5-7.5. Yours is fine.
P and K are both high as noted but this is often the case in Minnesota lawn soils. Potassium contributes to seedling development, maturation, and root growth. Phosphorus affects drought tolerance, cold hardiness, and disease resistance. Problems are seen when either of these are lacking, which is not the case for your soil.
Your soil test results reflect a fertilizer recommendation of 33-0-0 (N-P-K). You'll see on the lawn care calendar https://extension.umn.edu/planting-and-growing-guides/lawn-care-calendar that you should wait to apply it until August. The grass doesn't need it in the spring because the roots stored energy to make it through the winter and are using that now. Adding extra now would not be useful. Our lawn grasses are cool season grasses, meaning they grow actively in spring and fall. During summer months like July, they are relatively dormant and growing very little. They may even appear slightly brown - this is normal. Fertilizing grass during dormancy can stress the lawn by forcing active growth when it should be reserving resources for fall growth starting around August. Measure your area to figure out how many sq ft of lawn. You can purchase N for lawns as granular urea (pure N) at farm stores and garden centers. If your soil is dry, water your lawn before applying your fertilizer and after. Use a drop spreader or hand-held spreader to apply. When your lawn starts actively growing again in August, add N at a rate of 1 lb per 1000 sq ft. Again, wait to apply this in August.

Please read the section "Interpreting your oil test results" on the U of M Soil Lab website if you haven't already. This will give you background on the results: http://soiltest.cfans.umn.edu/understanding-your-report/lawn-garden-and-landscape-plants. Also be sure to read the back or second page of your results. It contains excellent information.


The soil test you submitted does not test for disease, only soil fertility. If your organic matter levels (noted on your report) are in a good range, you will need to look for other reasons for the bare spots because the soil isn't the problem.

When I enlarge the photos, I see some bare spots. There may be disease but due to the limitations of the photo and the difficulty diagnosing turf diseases from a photo, I can't tell. Often, a hand lens or microscope is needed to diagnose turf diseases. You suspect fungal problems. You could try sending turf samples to the U of M Plant disease clinic. Read their website carefully to learn how to submit a proper sample and under the heading "Submit a Sample", click on the "Turf" sample form link listed towards the bottom. https://pdc.umn.edu/

Check out this link to see common fungal infections in turf grass and compare to what you see: https://www.extension.iastate.edu/news/2006/sep/070801.htm You may need to wait until the grass is actively growing in order to figure this out on your own or before sending samples in. Note that antifungals should not be applied without definite diagnosis, nor are they useful when proper lawn care practices are absent.


There may be benign reasons for bare spots too, like earthworm activity or squirrel's digging. You may want to try roughing up the bare areas, over seeding, and observe. Proper lawn care alleviates many problems. Our Lawn Care website offers good information on how to properly manage your turf: https://extension.umn.edu/lawns-and-landscapes/lawn-care

Thank you for contacting Extension.

Dear Anita,
WOW!!! WHAT A GREAT, THOROUGH, KNOWLEDGABLE, WISE ANSWER!!! YOU ARE THE GREATEST!!!!!!
I will send a soil sample to the U of M Plant disease clinic...in a month or so when we can see some new growth.
THANK YOU SO MUCH FOR YOUR TOTALLY THOROUGH, KNOWLEDGABLE AND WELL THOUGHT OUT RESPONSE. I AM TOTALLY IN AWE!!! TOTALLY : )
Yours truly, Mr. Lynne Tiegs