Leave the leaves for a healthier lawn
FARGO — A headline contest would have been fun this week. Readers could submit titles like "Take it or leaf it," "Leaf well enough alone," "Leaf no trace" or "Don't leaf me this way."
What kind of leaf-raker are you? Do you fastidiously sweep every leaf from the lawn as it falls, or do you let them accumulate until a stiff wind blows your leaves in the direction of a neighbor who enjoys yardwork?
Raking autumn leaves is a Norman Rockwell-like tradition. Or alternatively, letting the lawnmower suck up leaves into the bagging attachment for removal.
Have you ever felt a twinge of guilt while mowing the lawn in October because you mowed over leaves and all, without first taking time to rake, but instead let the mower chew them up and spit them out? Was this the lazy way?
Surprisingly, mowing over fallen leaves and letting them remain is great for the lawn, and there's research to prove it. In the late 1990s, Michigan State University wanted a research-based answer to the question of whether it's better to remove leaves from the lawn or pulverize them back in.
During the extensive three-year study, scientists considered three different leaf layer thicknesses: none, 3 inches and 6 inches of mixed tree species, mulched in with a rotary mower every October.
In summary, mowing leaves back into the lawn proved beneficial for turf health. Lawn areas where leaves were mulched were healthier than the lawn area receiving no pulverized leaves.
Scientists stated, "Research clearly indicates that mulching leaf litter into existing turf grass provides benefits for the soil and turf grass plants by adding nutrients, retaining soil moisture, loosening compaction and reducing weed growth. After three years of mowing leaves into turf, dandelions and crabgrass were reduced nearly 100 percent in the study."
Researchers at Michigan State suggested using a rotary mower that pulverizes leaves well, such as a mulching mower or a mower with the discharge opening covered, and with the mower height adjusted to a high setting. Leaves should be dry, and mowing slowly with a sharp blade will grind leaves finer.
Several passes might be necessary, and it's best to mow leaves regularly, not letting them accumulate on the lawn for more than three or four days. The optimum time to mulch the leaves is when you can still see green grass through the fallen leaves.
Pulverized leaves should settle into the turf within a few days, and remaining leaf litter shouldn't be allowed to cover grass blades entirely. If leaves accumulate in a layer too thick to mulch, an option is to rotate by raking or bagging one week, then mulching the next.
The healthy effects of mulching leaves back into the lawn is most noticeable after following the practice for several years. Leaves are a natural soil-builder as they decompose. Besides Michigan State, mulching leaves is advocated by entities like Purdue, University of Minnesota, North Dakota State University, Consumer Reports and even Bob Vila.
Well, there you have it. Raking leaves may soon be a thing of the past.