Officials said the man got his hand stuck in a plant transplanter and his injuries were severe enough that Careflight was called to the scene.
The company's web site said the nursery supplies a variety of plants and shrubs to retailers in the Miami Valley.
It took emergency crews 30 minutes to free the man's hand from the machine.
A supervisor at the business told firefighters that the man was somehow pulled into the machine.
Battalion Chief Dave Nangle of the Springfield Township Fire Department said, "When we were pulling him out of the machinery after we freed his hand, we noticed his clothing was tied up in the machinery that was sliding back and forth. So we're not sure if he was actually drug up in the machine or actually placed his hand in it."
Careflight rushed the man to Miami Valley Hospital.
Since this was a workplace incident, fire officials said OSHA, the Occupational, Safety and Health Administration, will be called in to investigate.