Question
Hi,

I live in Southest Michigan, and we bought a 8 year old house 2 years ago. The lawn was beautiful and had no problems until last Fall. There was a misunderstanding between us and a lawn care company and they sent someone to apply the fertilizer just after my husband had applied it himself. After that, we noticed that the lawn started having some dried spots, where the grass would be completely dried (light brown color). The spots started getting bigger. We were told that if we water a lot it might come back.. It didn't.. So this spring, we planted seeds in those spots.. And some came back.. But now, new dried spots are appearing in other places.. each spot is at least 10 inches in diameter (not exact circles, of course).
Any ideas? Is it over-fertilization? lack of water?
We water every day for 10 minutes at each zone. Sometimes 20 mintues, depending on the heat.

thanks for the help..

ah, the house faces south. only the front yard has the spots..

Thanks again!
hasiabdu

Answer
I can't say for sure what is causing the spots, but provided you have not fertilized again, then I would not think overfertilizing is the problem.

It could be insects (grubs in particular). Dig into the root zone between the brown and green grass and look for c-shaped white maggits. if you find more than 1 or 2, then apply a grubicide (such as GrubEx by Scott's). Reseeding of brown spots may be needed.

To establish the seeds you do need to water frequently and shallowly such as 10 minutes every day or every 2nd day. However, once the grass starts to green up, you need to gradually change to an infrequent but deep watering pattern, such as once per week for 2 hours. A mature lawn (+4 weeks old) should always be watered infrequently and deeply to thoroughly set the soil profile to a dept of 8-10". This you can not do by watering frequently and shallowly.

Over a period of 4-6 weeks, start to increase the time between watering and the amount of water you apply. After 4 weeks, you should be watering only once per week but for a long time (2 hours) when you do water.

If you need to reseed new grass, then you must again switch to a shallow/frequent watering pattern because the grass seeds die without constant moisture. but once the new grass starts to grow, gradually change to an infrequent but deep watering pattern.

By watering deeply you increase the heat and draught tolorance of the grass.

EG
- mow lawn high (2.5-3.5" after a cutting) and mow frequently
- fertilize in late spring, early fall and late fall. Don't fertilize during hot summer months
- except for seed establishement, water infrequently and deeply such as once per week for 2 hours.
- check for grubs.

If you do not find grubs, then I suspect that your lawn has become stressed from shallow watering. Changing watering pattern and applying grub-ex may help.