The two most important facets of lawn mowing are mowing height and frequency. The minimum height for any lawn is 2 inches. The preferred mowing height for all Ontario species is 2.5 to 3.5 inches. Mowing to less than 2 inches can result in decreased drought and heat tolerance and higher incidence of insects, diseases and weeds. Mowing the lawn at the same height all year. There is no reason for mowing the lawn shorter in late fall.
Mowing the turf often enough so no more than 1/3 of the grass height is removed at any single mowing. If your mowing height is 3 inches, mowing the grass when it is 4.5 inches tall. If weather or another factor prevents mowing at the proper time, raise the height of the mower temporarily to avoid cutting too much at one time. Cutting the grass again a few days later at the normal mowing height.
During the season, regularly check mowing equipment for sharpness and adjustment. Sharpen mower blades every month, especially when mowing thick wet lawns. A dull mower blade will shred and fray leaf blades instead of cutting them cleanly. The result is a brown, unattractive lawn.
Thatch and Clippings
Let grass clippings to fall back onto the lawn, grass clippings decompose quickly and provide a source of recycled nutrients and organic matter for the lawn. Mulching mowers can do this easily if the lawn is mowed at the proper frequency. Grass clippings do not contribute to thatch accumulation.
The idea that clippings left on lawns will cause thatch has been disproven. Thatch is a brown, spongy material consisting of dead grass stems and roots.
Excessive thatch is undesirable because it prevents water and air from penetrating to grass roots. A healthy population of microorganisms and earthworms in the soil can digest thatch. Grass clippings break down quickly and encourage the beneficial earthworms and microorganisms that maintain healthy grass and healthy soil. Regular core aeration is the best way to prevent thatch.