Knowledgebase
Pest identification and steps to take #919728
Asked October 11, 2025, 3:15 PM EDT
Hennepin County Minnesota
Expert Response
HI Ann,
This could have a few causes. If it was caused by moles you’d see signs of their tunnels, with pushed-up turf. Voles are more of a threat to trees and shrubs than to lawns.
Especially on older lawns, earthworms often causes bumpiness.
See these pages:
https://yardandgarden.extension.iastate.edu/how-to/bumpy-rough-lawns
https://apps.extension.umn.edu/garden/diagnose/plant/turf/bumps.html
https://extension.umn.edu/planting-and-growing-guides/vole-damage
The site below has good suggestions on how to fix a bumpy lawn created by earthworms. However, in Minnesota using a heavy roller on a lawn is NOT recommended because on our soils grass will be damaged when soil is compacted. The rest of the suggestions are good.
https://cmg.extension.colostate.edu/Gardennotes/554.pdf
Hope this helps. Thanks.