Back in the day, the work done in the fields and on the ranches of the North Bay was horse-powered, literally. This weekend, the North Coast Draft Horse and Mule Association hosts its annual Plowing Day at the former home of Jack London to give visitors an insight into the history and experience of farming in the 1800s. The family event includes plowing demonstrations and free wagon rides around London’s ranch, and features an array of horses on hand. Blacksmithing, horseshoeing and other throwback practices will also come alive on Sunday, May 21, at Jack London State Park, 2400 London Ranch Road, Glen Ellen. 10am. Free admission; $10 per vehicle parking. 707.938.5216.