There is a good Farmers Market every Thursday in Washington, about 30 miles south of Iowa City. Things get started about 5:00, and sometimes there are other events, too, like music. Locally grown produce and flowers, plus baked goods (Amish) and some 'imported' produce are sold. Often you can purchase food to eat right on the spot.
The market is located on the square in downtown Washington. If you arrive via highway 92, the main east/west highway, you will find the square easily - just keep your eyes open! If you're coming from the north or south, use highway #1 which junctions with hwy. 92 on the west side of town.

Belle Plaine Farmers Market every Friday 5-7 p.m.
Williams Park
June 4th to September 24th

Grinnell Farmers Market
May 27th to October 14th
every Thursday 3-6 p.m.
Central Park 4th Ave. & Broad St.

Every Saturday
June 5th to October 9th
8:30-10:30 a.m.
Main St.