On a brisk fall morning, with the dew still fresh on the grass, volunteers in their old T-shirts and blue jeans listen as Tracy Blackmer shared instructions for their day on the farm.

As soon as he walked them out to the garden, the volunteers got to work picking. They quickly filled several plastic crates with an assortment of peppers in pop-art colors, a bright contrast to the golden corn field behind them.

As of mid-September, the Blackmer family has grown more than 18,000 pounds of produce on their farm. But they haven’t sold a single red tomato or lone green bean. All of their fresh produce is donated to the Food Bank of Iowa.

The Blackmers call their project Garden for Good. And indeed, the 3-1/2 acre garden has done a lot of good for many Iowans.

It’s provided food for families across the state who can’t afford to buy fresh produce on a limited budget.

It’s become a community gathering spot for volunteers — co-workers,...