High tunnels are plastic-covered, passively ventilated and heated structures where crops are grown directly in soil. They have become important tools for Iowa specialty crop producers to increase production of quality crops, extend the season, and increase profitability. The environment in a high tunnel, without rainfall, limited space, and potential climate control requires a unique set of crop management skills. High tunnel production is primarily dominated by tomatoes. Interest among growers focuses on year-round production in high tunnels.