Diseases caused by the soilborne fungus Sclerotinia sclerotiorum can affect a wide range of plants with yield losses ranging from 10 to 50%. Sclerotinia diseases can be particularly problematic in high tunnels where high-value vegetable crops are planted in late winter for earlier harvests and higher profits. Fungicide applications and crop rotations are limited due to product availability and profitability windows. In a two-year study, soil solarization was determined to raise soil temperatures as high as 120?F in mid-summer; lethal temperatures resulted in 99% mortality of S. sclerotiorum in test plots. Though maximum temperatures in spring and fall solarization trials did not match those of summer trials, mortality reached >80% in spring and >85% in fall trials as soil temperatures reached >100?F. Management of Sclerotinia diseases can make positive impacts to the >1,500 high tunnels in Kentucky. Solarization in high tunnels is a means for low-cost, pesticide free management of S. sclerotiorum. Research results and grower recommendations are available online and at Extension events.