Question
I live outside Chicago, IL in a southwest suburb.  I have been noticing brown spots throughout my lawn during the last two weeks.  Should I spray my lawn for insects (grubs) or could there be another reason for the brown spots?  I believe I have fescue grass. In addition, how do I keep my grass green during the summer without a lot of growth?

Answer
You can check for grubs by trying to lift the dead grass up. If it comes off the ground like a carpet (indicaton: roots have been severed) it may be grubs. You can dig into the root zone between the green and the brown turf by slicing the sod with a spade. Gently lift the top of the sod with a a few inches of soil attached. Poke around in the ground and look for white c-shaped maggits. If you find more than 1-2 then apply Grub-Ex now.

After you are done, replace the turf and keep the spot well watered for a few weeks to ensure rooting again.

To keep your lawn green without excessive growth, avoid fertilizing in spring or summer. In future, fertilize in early and late fall (early september and late october). Then do not fertilize again. If you like the grass to green up and grow in spring, a single application in early May (1/2 strength) can be used also.

Then make sure you water your lawn regularily through the summer. Most of the summer showers/thunderstorms we have provide far less water to keep grass actively green. Unless you have a storm which puts down 1" or more of water, then I recommend watering once weekly for 2-3 hours to give the lawn a through soaking. when daytime temperatures are above 90 deg F you can even water twice per week. However, make sure you water deeply (such as 2-3 hours per application) rather than 15-20 minutes.

Tall fescue should stay green through summer if you follow above. Fine fescues (hard, chewing,creeping red) is very fine "needle"-like grass hairs which are very susceptible to hot temperatures. fine fescues may not stay green through a hot summer, but should recover in fall. Again, keep the watering pattern as explained above.

Tall fescue is rather wide leaved tall grass compared to fine fescues which are needle thin, very fine (like baby hair). Tall fescue is draught tolorant and can tolorate hot temperatures. fine fescues can not. The browning of fine fescues through summer is quite normal and should not worry you.

Brown spots can occur for a number of reasons (it is like taking your car to the mechanic because it "makes a sound").

Besides general browning due to lack of adequate water, or due to grubs, browning can happen because:
- undesirable grasses (grassy weeds) have infiltrated the lawn either through drifting or through overseeding with low quality grass seeds. Some of these grassy weeds may look like regular green grass, but they may not be able to withstand the summer heat. Some grass types are green in spring but turn brown in summer.
- other insects than grubs. example: chinc bugs.
- lawn has a fungus or lawn disease. These mainly come around from being watered and fertilized wrongly, although perfectly healthy lawns can get lawn disease especially in years with very wet and humid spring and summers.

To limit lawn disease always:
- fertilize mainly in fall (less so in spring. never in summer)
- mow the lawn tall and mow frequently. it is better to mow at 2.5-3.5" tall (4" for tall fescue) than 1.5-2" (meassured after mowing)
- water infrequently but deeply when you do water. avoid frequent shallow applications. If the weather has been "wet" but not a lot of rain has accummulated, it can help to still water deeply once per week.

However, consistently wet weather can also cause grass leaf diseses if the forces of nature are against you. Sometimes there is simply nothing we can do about it. You can always try to minimize any damage by correcting your fertilizing, mowing, and watering techniques as above. Then you have at least given the grass the best you could do and it is up to the grass to fight off any disease accordingly.

One last note: when watering, water in early morning hours if you can. you can even water after midnight, but try to avoid watering in late afternoon/early evening. Watering at night is not a problem because the lawn is anyway wet from dew. However, if you water in late afternoon/early evening, the lawn may not get a chance to dry off before night time and the extended leaf wetness period is what causes disease. If you can, try to water in early morning hours (before 8 am) but even midnight or 2 am is acceptable (use a watering timer). A midday watering is also an alternative, but generally a lot of water is wasted to evaporation in this manner. Avoid late afternoon/early evening watering.

Good luck