The importance of mowing high in an all natural turf care program cannot be stressed enough. Applying the proper organic and all natural materials while important cannot make up for improper mowing.
I was recently called in to look at a sports field where the trustees wanted to go organic. They were concerned that the field was not responding. What I saw was a bluegrass sod field that was infected with leaf spot. I believe the major contributor to this condition was the fact that the field had been cut at 1 ½ inches.
The fellow that mows the property says that his equipment cannot cut the field that short. Yet he has never checked to see at what height the blades are off the ground on his mower deck. Do not rely on the markings on the mower. An easy gauge for cutting at 3 inches is as simple as nailing two pieces of 2 x 4 together and slipping them under the blades. Tip them on their side and you have a gauge for a 3 ½ inch cut. I must also make the important point: PLEASE DO NOT DO THIS WITH YOUR EQUIPMENT RUNNING.
Improper tire inflation can also affect the height of cut. Routinely check tire inflation and also the dolly wheels on the mower deck. More than once I have seen fields scalped for lack of proper inflation or a missing roller on a deck. The operator blithely went on mowing without ever looking to see the results of his efforts.
Leaving the clippings is also important. It has been our experience that clients that routinely had their mowing service provider routinely remove clippings the level of organic matter in the soil also went down year after year to the point that the soil conditions would not support desirable soil biology. Earthworms love clippings and are ten times better than any mechanical means for aerating the soil. Water absorption, both speed and amount, is directly related to the number of earthworms living in the soil.