Parts 1 and 2 of this series have encouraged readers to water and fertilize less than in spring and fall, which dovetails nicely with the topic of part 3, which is to mow less often. Reducing mowing frequency is important as the process of mowing creates openings in the ends of grass blades, allowing them to lose water. This guideline is most helpful at the beginning of a drought, or a program of allowing drought to occur, because as time wears on, the reduced irrigation rate encourages less growth and thus, less need for mowing.
When you do mow, it’s important to use a sharp mower blade. Keeping the blade sharp will decrease the size of the openings made in each blade. In addition to encouraging foliar disease, dull mower blades tend to rip and tear the grass blades, which allow more moisture loss.
Raise the mowing height? Moderate increases in mowing height create a “canopy effect”, that functions to shade the crowns of the plant a bit, reducing stress. As well, there is a direct relationship between the height of cut and the depth of the root system, in that the higher the cut, the deeper the roots, which is good for absorbing moisture from the soil. However, these benefits are offset by the greater surface area that is produced by raising the height and a reduction in density of the lawn, as higher the cut, the fewer the number of plants per square foot of turf remain. Overall, the plusses and minuses tend to cancel each other out, which leads to our recommendation of not changing the mowing height – aka – “set it and forget it”, as Ron Popeil would say.
Ok, if we’re not going to raise the mowing height, how about returning the clippings? A light sprinkling of grass clippings will act as a mulch for the grass plants, holding in soil moisture and keeping the crowns cooler. It’s wise to avoid clumps of clippings which smother the turf plants, so staying on the 1/3 rule, where no more than a third of the turf surface is removed with any one mowing pays dividends. Again, this is less of a problem as hot weather continues, because less growth is produced.