The fire started around 6:45 p.m. near the 8100 block of Jamacha Road, said Brian Anderson of the San Diego Fire-Rescue Department.
The fire was under control by 7:30 p.m., Anderson said.
No structures were threatened or damaged, Anderson said.
The fire was caused by arson, according to a San Diego Fire-Rescue Department dispatcher.
No one witnessed the start of the fire, she said, adding that no information was immediately available on what led investigators to conclude it was the result of arson.