Ten acres was all it took to affirm Doug Sorensen’s thoughts about the value of the Furrow Brow, his homemade invention to keep mud from building up on planter depth gauge wheels.

After using the (then yet-to-be-named) Furrow Brows since 2007, Sorensen switched to a different planter in 2015 that didn’t have the attachments.

"I went one year without them and decided I’ve got to have something (to...