He estimated the lump of what he believes was fertiliser would have been about the size of a football, or slightly bigger.
"It's covered our entire deck area, there are even spots around the driveway below. It certainly wasn't just a little dusting."
Mr Stevens said he had noticed the plane, which in his opinion was flying low.
"I'd imagine this kind of thing wouldn't happen very often."
He said he had contacted the Civil Aviation Authority and the Bay of Plenty Regional Council about his concerns.
"I just wanted to know whether there were regulations."
A Civil Aviation Authority spokeswoman confirmed it had received a call from Mr Stevens and was waiting for formal notification before it could investigate.
A regional council spokeswoman said the council had received Mr Stevens' complaint.