Hi Rory,

I'm sorry to hear about your lawn!

To help me better understand what may be happening, could you please tell me:

1. What type of grass(es) is/are in the lawn, if known? Eg Kentucky Bluegrass, Fescue, etc.

2. How is the lawn watered, and how often for how long?

3. What sort of fertilizer, if any, does the lawn receive?

4. When did you first notice the problem?

5. Can you describe the mushrooms you mention--when do you see them, what do they look like, and do they grow in any discernible pattern?

Thanks!

John

Ok, thanks.

A couple of things come to mind.  First, have you ever conducted an "irrigation audit" on the lawn?  This is a way to be sure that your sprinkler system is applying water evenly.  Uneven watering could cause brown spots, including the type that you are observing.

Second, it's possible that you have a weedy turfgrass species in with your lawn called "roughstalk bluegrass".  This grass is extremely intolerant of heat and will go dormant in the summer, often despite adequate water.  Roughstalk bluegrass is poorly rooted in general so the brown spots would pull up easily, like a bad toupee.  Close inspection of the horizontal stems would show characteristic "onion skin" surfaces.  If you could take a close up picture of some grass tat you have removed from the lawn I might be able to tell, otherwise, you could bring a sample to the office in Castle Rock for me to take a look at.

Third, you might be seeing damage from white grubs--these would be readily visible upon excavation of the brown spots, a few inches down.  Enough grubs to cause the damage you're seeing would not be difficult to find.

The pattern does not look characteristic of any lawn disease, and the mushrooms you are describing are decomposers--feeding on dead organic matter in the soil, not living lawn.  These types of fungi can cause locally dry spots, though--digging in the affected area would reveal white fungal threads in the soil.  You would also expect to see the mushrooms growing at the "leading edge" of this dry spot.  

If you are able to bring a sample of the lawn for me to check to the office in Castle Rock I can perhaps get closer.  I would need about a shoebox-size sample of turf that includes a transition from unhealthy/brown to health/green lawn. (you can take the sample home with you after diagnosis to repair the turf).  

Cordially,

John

Hi Rory,

It looks like our system does not like zip files so I can't see the additional photos.  Could you please attach them in a different format?

Thanks!

John

Thanks, that worked.

Well, it does not look like roughstalk bluegrass from what I can see in the photo, and the mushrooms are, again, not pathogenic but saprobes, living on decaying organic matter in the soil.  

I suspect watering may be much of the issue that you're observing--have you been able to conduct an irrigation audit yet?  

One strategy that you could take now to try to thicken the lawn up again in this area would be to heavily core-aerate the area (with holes on 2" centers) and then over-seed with good quality grass seed.  The grass should still have time to germinate and mature enough to overwinter this fall if you do this in the next week or so.  Otherwise you could wait to do it early next spring (April).  

I hope this is helpful.

Good luck!

John

I'm glad we seem to have gotten to the bottom of the issue, and I hope you have good luck with greening the lawn up again.

Have a great day,

John