As June fades into July, there are definite guidelines on what you, as a homeowner should do and not do as it relates to your lawn. The most important and often discarded piece of valuable turf information is mowing height. Like a doctor speaking with a patient, mowing is one of the most important pieces of advice a homeowner can follow. Even if you have your lawn professionally cut, this does not automatically mean the job will be done right. I have seen too many commercial lawns scalped or mown below 2” during the summer, only to become stressed weakened and prone to both weeds and crabgrass.
So what is the ideal summer cut? For most lawns, sun or shaded situations call for a high cut at 3” or maybe a little higher. Sunny areas are prone to stress when cut in the middle of a hot day, predisposing them to all kinds of heat and mower stress. As the grass is cut, depending upon the sharpness of the blade, the leaves lose water and can brown with the increased moisture demand. Said another way, if you cut something, it bleeds – in this case a grass blade is mostly water. When a mower cuts it, especially during the day, and below 2”, the lawn loses moisture rapidly. If the soil is dry and cannot support replacing this moisture loss, you can see browning the same day or shortly thereafter. These areas can appear as brown patches, yellowing, or widespread discoloration depending upon the time and day temperature.
The shorter the mowing height, especially as it approaches the 1” level, the more substantial damage can be caused from June through August. The shorter the cut, the hotter the soil becomes, causing weed seeds to germinate. Any pre-emergent barrier that may have been put down pre-maturely degrades, allowing weeds to germinate unnecessarily. Removal of grass clippings may provide an aesthetically pleasing view, but it removes critical organic matter week after week. There may be an occasion for this procedure, but on the whole, grass clippings should be mulched and returned to the lawn surface like leaves falling in a forest. This way, whatever energy and professional care you are putting into your lawn will not go to waste but will provide the most benefit possible.