Question
I am new to the Chicago area and I am having trouble diagnosing my problem.  I have brown patches in my yard.  They seem to be concentrated in the part of my yard closest to the house, where my dog doesn't usually relieve herself.  I put down spray for fungus with no improvement.  And now, I've noticed 4-5 more spots that just came up. Could this be due to grubs?

Answer
Hi Heather;
It could be grubs, it could be brown patch, or it could be not enough water.
If the soil is very hard clay soil, water will not penetrate deep enough to reach the roots.
I have been on an organic program, and the lawn critters take care of all the harmful insects, so I am not sure if the Japenese beetles layed eggs and they hatched into grubs yet.
Take hold of a handful of grass, and see if it pulls up easily, with no or not much of a root attached, and has a slightly to severe slimy feel, where the rioots would be.
That would be a fungus.
I use baking soda disolved in water to treat fungus, and that works for me better than chemical fungicides ever did.
If you just treated it within the last week, it may not have had time for the grass to start filling in.
If that is the problem you would have to treat the whole yard to stop the spread of it.
Put a shovel in the ground and turn over a spadeful of soil. See if you see grubs, and if so, how many.
If in that spadeful you see 6 or more, grubs are a problem. whether they are solely responsible may not be the case, but that is enough to know you need to treat for grubs.
To find out if the problem is clay soil, water long enough to soak opart of the ground. I would just run the hose, no sprinkkler or anything, till you have a puddle. See how fast that soaks in. then dig a little tosee how deep the water penetrated, or just notice how hard it is to get a shovel into the ground.
I always water to a depth of at least 6 inches to encourage a deep root system.
Deep root systems help protect against heat, cold and drought damage, and prevents a thatch buildup.
shallow watering causes the roots to come to the surface to get water. As soon as the top inch or two is dry, the roots are exposed to killing heat.
Dead roots on top of the soil attract other debris and cause a thatch build up. That is a waterproof pad that won't let water ot anything else through to the roots under the ground, so everything dies.
Since it is occuring in spots, that sounds more like fungus or grubs.
I use 1/4th cup baking soda per gallon of water.
I am unable to find out exactly how much soda is enough, so since that amount works, I have just continued to use it.
Spray the area well to soak the grass and the soil to at least 3 or 3 inches down.
That should sstop it if it is broen patch fungus.
Charlotte