Small Engines (Lawn Mowers, etc.): John Deer 111 Riding mower, rocky soil, john deer

Question
For the last three years I've been cutting my lawn at 2.5" with a John Deer 111 tractor mower. Suddenly I start getting "bald" spots all over the yard at the same level. I tried adjusting the blade deck upward. But the mower still cuts very inconsistantly. What could be the problem?

Answer
Does your lawn need to be rolled due to rodents under the grass making these high spots?  I have also seen rocks migrate to the top of the lawn over time.  this is always in very rocky soil or if lots of building debris was buried on your lot.  

If that is not it check the anti scalp wheels.  They are the plastic rollers or wheels attached to the out side of the mowing deck.  In the desired cutting height they should be 1/4" off the ground on a flat surface, such as your driveway or garage floor.  Replace if worn or readjust.

Next would be blade condition.  Is there a bent blade? Are the correct blades on the mower?  Is the mower deck out of adjustment? Is any of the hardware that supports the deck broken or missing? Do you have low tire pressure?  Most are 12 osi.

Get your owners manual out and follow the directions to level the deck.  If you do not have the manual contact John Deere to download a new one for your model and serial number tractor.

If none of this did you hit something and bend the deck?  

Hope this helps.