We have been growing wheat grass for several years and juicing it daily. After much research and experimenting we have learned that a small amount of baking soda (about 1/2 tsp to a gallon of water) in the watering can keeps mold away for the most part. We use this same water for soaking the wheat berries before planting, on the soil before we plant the seeds, in a spray bottle to spray the little sprouts, and of course for watering the wheat grass as it grows. Hope this helps you... Happy Wheat Grass Growing and Juicing!