Lawns are growing quickly and seedheads are appearing (2024)

Kevin Frank<frankk@msu.edu>, Michigan State University Extension, Department of Plant, Soil and Microbial Sciences - May 28, 2020

Following cold temperatures throughout most of May, recent warm temperatures and rainfall have lawns exploding in growth. If you’ve fallen behind on mowing, Michigan State University Extension recommends raising your mowing height to avoid leaving massive piles of clippings on the lawn, or consider this a time when you can be justified in picking up clippings to avoid smothering the turf. Another smart reason to raise your mower height is to promote deep roots, avoid grub damage and crowd out weeds.

In addition to surging top-growth, seedheads are also appearing. The common lawn grasses – Kentucky bluegrass, perennial ryegrass and tall fescue – all produce seedheads as do grassy weeds such as annual bluegrass (Poa annua). Seedhead production requires energy from the plant, so it is likely the turf will not only look stemmy due to the seed stalks, but the turfgrass may even lose density.

Consider a fertilizer application following the seedhead flush to help the turf recover, especially if you haven’t fertilized yet this spring or fertilized back in April. Keep the mower blade sharp to ensure a clean cut and don't lower the mowing height to try and remove seedheads. Annual bluegrass produces seedheads below the 0.125-inch mowing height on golf course putting greens, so lowering the mowing height is not going to eliminate seedheads from your lawn.

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