Sound mowing practices are necessary to obtain a good quality lawn. This is especially true during the summer months. Improper mowing practices during periods of drought and high temperatures may seriously damage turfgrass.
Kentucky bluegrass lawns should be mowed at a height of 3 to 3 1/2 inches during the summer months. Bluegrass lawns should be mowed at a height of 2 to 2 1/2 inches in the spring and fall. The additional leaf area during summer shades and cools the crowns of the turfgrass plants. During hot weather, the temperature near the crown area of short-mowed turfgrass may be 20 F or more above the air temperature. Extremely high temperatures at their crowns can kill turfgrass plants. The higher mowing height also provides more food-producing foliage and promotes deeper root growth.
When mowing the lawn, never remove more than 1/3 of the total leaf area at any one time. Removing more than 1/3 of the leaf area severely injures the turfgrass plants and reduces their ability to withstand additional environmental stresses.
If possible, mow in the cool of the morning or evening. Mowing at midday places additional stress on the turf and may also cause heat stress related problems for the individual mowing the lawn.
Another important key to proper mowing during the summer months is a sharp blade. Dull blades tear and bruise the leaf tips. The damaged tissue dries out giving the turf surface a whitish appearance. The damaged leaf tissue also suffers greater water loss. The mower blade doesn't have to be razor sharp. A properly sharpened blade has no nicks and is smooth on the bottom with a 30 to 45 degree bevel towards the top of the blade.
Change the mowing direction or pattern each time the lawn is mowed. Different mowing patterns reduce soil compaction and turf wear from the mower wheels. Wear damage is most likely in thin or shady areas. Also, mowing the lawn repeatedly in the same direction pushes the grass over rather than cutting it cleanly.
Dormant lawns (those that have turned brown) should not be mowed. Pedestrian and mower traffic could damage the turf. Grass that is still growing should be properly mowed following recommended practices.
This article originally appeared in the July 25, 1997 issue, p. 122.
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