Sharply cut leaf blades increase turf health by improving recovery, decreasing water loss, and increasing photosynthesis. Lawns mown with a dull mower blade have poor aesthetics, heal more slowly and have greater water loss. Seedheads are present in many lawns right now and they are typically tougher to cut than the grass blades themselves. As such, it might help to switch to a sharp set of mower blades to help slice through these seedheads.
Homeowners should sharpen mower blades at least twice a year. To make this easy, buy two sets of mower blades and sharpen both sets each winter. Put a sharpened blade on before the first mowing and then switch when you notice that the leaf blades are becoming ragged in appearance as this is an indicator of a dull mower blade.
For professionals, consider sharpening mower blades weekly, bimonthly, or monthly depending on the amount of turf you are cutting. Again, inspecting the turf leaf blade is the best way to determine when your mower becomes dull.
Aaron Patton, Turfgrass Extension Specialist