The cutting of your grass and how its done can be as important as other cultural practices, but cutting is often overlooked as a mechanism to help maintain a healthy lawn.
When deciding on how often to cut your grass, you need to consider several factors which will influence when to cut.
The most critical decision is the height of the grass. It is important that you not cut the grass too short, or leave it too long. Cutting the grass too short leaves it susceptible to burning and weed and insect infestation. Leaving the grass too long may mean you’ll be cutting off a great deal of the blade when you do finally cut, and this damages the grass. Ideally, you want to cut your grass when it reaches a height of about 3½ inches. Plus, in the spring and summer, we recommend you cut your grass to a height of 2½ to 3 inches. Maintaining this cutting height will ensure you don’t cut too much blade off, which will stress the grass plant, and will keep it at a length which will help it survive any drought condition. As well, at this height, your lawn will help prevent weeds seeds from germinating.
Grass clippings can help or harm a lawn. If you leave very small, short, finely cut clippings that decompose quickly, this is good! Usually a good mulching mower, if used when the grass is not too long, will mean the clippings can be beneficial to your grass. These clippings will return nutrients to the grass relatively quickly, and will not contribute to a thick layer of thatch.
However, if you do not mulch, or you do not cut your grass as regularly as you should, then leaving the larger, longer clippings may harm the lawn. These clippings are best removed immediately as they will block out sunlight, create thatch build-up, and even cause fungi or insect infestation.
At a recent lawn care symposium we attended, it was noted that many homeowners are now using the clippings from their lawns as compost, often then using the compost for gardens. Note that if we have applied weed control spray on your lawn, you should not use the clippings for at least two cuts. While damage to your garden plants is not probable, it is possible, so wait for a few weeks before you start to compost again.