Andrew Erdle, 27, a copywriter, grew up on a grape and blueberry farm in upstate New York. When he moved to Hell’s Kitchen five years ago, he expected to garden in containers rather than acres. But he didn’t expect to forget what he planted, and where.

The cheap plastic tags that came with his plants soon eroded, so he designed more durable labels in zinc-coated galvanized steel.

The parachute-shape markers were named Carl after a childhood neighbor who was a Vietnam veteran and avid gardener. They were also inspired by soldier toys Mr. Erdle owned in his youth, and by a photo of his step-grandmother wearing a sweater with a parachute motif. “It’s a pattern you could get away with wearing today,” he said.

A set of five markers, each about 7 inches by about 3 inches, is $20 at gooderdle.com.