Whenever I see unhealthy turfgrass, my first advice is to relieve plant stress. Relieving plant stress may involve adjusting the amount of water or air in the soil, optimizing the availability of essential plant nutrients, increasing the mowing height to allow more light absorption by the leaves, and very important but sometimes overlooked is this: cutting the grass cleanly.

My front lawn near Bangkok has three sections. Near the driveway is St. Augustine grass (Stenotaphrum secundatum), in the center section is centipedegrass (Eremochloa ophiuroides), and in the corner in broadleaf carpetgrass (Axonopus compressus). I took a selection of photos from the St. Augustine grass section last week, showing the damage that can occur when mower blades are not sharp or are not adjusted properly. Because St. Augustine grass has a wide leaf blade, the damage from dull mowers is especially evident in these photos.

The tip of an unmown St. Augustine grass leaf has a boat-shaped tip. This is how a normal leaf tip looks, at right, with no damage at all from mowing. Once we mow the grass, what kind of damage can we expect? Remember, by relieving stress on the grass, we can make it healthier. If we have healthier turfgrass, we can manage it to create the desired playing surface. Obviously grass must be mowed to create the desired playing surface, so we need a good plan for mowing to avoid putting undue stress on the grass.

Here is another leaf of St. Augustine grass from my lawn, but it has been mowed. You can still see the V-shaped leaf, but the boat-shaped tip of the leaf is now gone. A small amount of yellow scarring is visible at the mown tip, but this is a basically clean cut with no shredding. This is the type of clean cut you want because it minimizes the stress on the turfgrass plant.

At bottom right is what you don't want to see when you mow. This is another St. Augustine grass leaf from my front lawn. The damage and shredding at the leaf tip from cutting with a dull mower puts stress on the grass and causes a problem with plant health, with visual appearance of the turf, and eventually that causes a problem with playability as well.

So to relieve stress on your turf, make sure that you are mowing with sharp, well-adjusted mowers, and that you are getting a clean cut and not one that is shredding the turf. Sometimes from a distance you can see a whitish or yellowish tinge to the grass; upon closer inspection (get down and have a look at the leaf tips) you may see that the leaves themselves are green and healthy but the leaf tips are shredded and damaged by the mower.

Also, think about what mowing height is appropriate to give the desired playing conditions and appearance. And if you mow the grass with a thoughtful and creative mowing pattern, you can improve the appearance of the grass while reducing some other inputs.