About 100 firefighters responded to a 1:22 p.m. call that grass was burning near a vineyard at 2765 Blucher Valley Road, which is in an unincorporated part of Sonoma County, Cal Fire spokesman Michael Selmi said.
The blaze was going to be contained to 2 acres, Selmi said, but spot fires caused more than 3 additional acres to burn.
Six engines, four planes, and three hand crews were used to help battle the fire.
Firefighters contained the fire at about 2:40 p.m., and put it out at about 7 p.m.
No injuries were reported. The cause of the fire is still under investigation.