What’s your lawn philosophy? Do you meticulously groom and coddle each grass blade to perfection? Or maybe you only mow the lawn when searching where you left the wheelbarrow.
Many of us are somewhere between the two. No matter our lawn care viewpoint, many lawns around the region looked crummy this spring, and I received more emails and phone calls about the topic than any other gardening question in recent months.
Many lawns were badly matted, thin, anemic-looking, riddled with dead patches, dotted with small dirt blotches and bumpy enough to turn an ankle while walking.
What happened? A series of separate lawn plagues all descended since last fall, causing multiple disorders. Let’s examine them each, with recommended solutions.
Matted, moldy grass
When snow disappeared this spring, many lawns were matted down, often with gray or pink moldy patches. Snow came early, stayed late, and grass suffered under the weight and longevity of cover.
Fluffing up the grass by raking is the best medicine, which has been accomplished on most lawns by now. The mold usually disappears quickly by raking, but can kill grass patches if left in its matted condition.
Bumpy lawn, small dirt mounds
The next issue to appear on many lawns was a multitude of small, half dollar-sized mounds of soil sprinkled through the lawn, making the lawn not only unsightly, but the bumpiness is like walking across a field of golf balls. The cause has been nightcrawlers and other earthworms working very close to the soil surface due to last fall’s heavy rains making soil supersaturated.
Alan Zuk, a turf management professor at North Dakota State University, says the bumps are called "worm castings" and can be mitigated by light power raking. He indicates earthworms are protected species, so we’re not allowed to use chemicals to control them. There are no pesticides labeled for nightcrawler and other earthworm control.
As lawns dry, worms tend to move deeper into the soil. When watering lawns, water deeply and less often to encourage worms to move deeper.
Yellow, anemic-looking turf
Many lawns began spring looking more like a patchwork of yellow mixed with light green than a uniform rich emerald color, with several probable causes.
Heavy rains last fall and generous snow melt might have leached nitrogen away from grass roots, leaving turf nutritionally deficient. Grass plants might also be low in iron, causing yellow, chlorotic conditions common when soil is cold and wet, as it’s been this spring.
To remedy pale turf, apply lawn fertilizer following label rates and instructions. Fertilizers containing iron can restore green color if iron deficiency is suspected. Lawns are best able to utilize fertilizer most efficiently after the grass is green, actively growing and soils have warmed as we get closer to Memorial Day. As soil warms naturally, many lawns improve as grass roots become more active and can utilize existing soil elements.
A soil test gives a good analysis of the current soil quality. Information for submitting samples to the NDSU Soil Testing Lab can be found at www.ndsu.edu/fileadmin/snrs/Files/lawn_and_garden_.pdf; University of Minnesota soil testing information can be found at soiltest.cfans.umn.edu/sites/soiltest.dl.umn.edu/files/media/lawn_and_garden_2018_3.pdf.
Lawn care recommendations
Turf becomes most healthy when we give grass its natural preferences over extended years. Roots grow deeper, weeds are reduced and the lawn becomes more self-sustaining with the following recommendations.
Autumn is vital to grass health, as roots grow deep and nutrition is stored for winter survival and early spring growth. Fertilizing around Labor Day is the single most effective time for long-term lawn health. Apply again around Memorial Day.
When sprinkling lawns, water deeply and less frequently, providing 1 inch per week in one application, or two if soil is sandy. Raise the mowing height to 3 inches; low mowing causes a weaker turf. Let grass clippings filter back into the lawn; they release nutrition as they decay, plus conserve moisture and block weeds.
Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at firstname.lastname@example.org or call 701-241-5707.