IOWA CITY, Iowa – August is prime time for tomatoes in Iowa, and heirloom tomatoes will take center stage during an Aug. 25 event by the Johnson County Master Gardeners. The Ninth Annual Taste of Heirloom Tomatoes is scheduled for 2-4 p.m. Sunday, Aug. 25, 2024, on the east lawn of the Plum Grove Historical Home, 1030 Carroll St., Iowa City.