The article linked below speaks of growing stevia hydroponically. Apparently it thrives when cultivated this way. It might be a viable alternative for commercial production of stevia. Maximum Yield - Indoor Gardening
Jeffrey Goettemoeller is the author of Stevia Sweet Recipes: Sugarfree—Naturally!, with over 300,000 copies in print. He also majored in horticulture at Northwest Missouri State University and completed a published research study on the production of Stevia rebaudiana seeds. Jeffrey attended Catholic seminary for a few years and has been a pro-life advocate most of his life.