BUY ORGANIC ONLY. Also, if you want to grow your own tree or plant from, say, an organic avocado you bought, you have to let the seed dry out _completely_ before trying to grow it. When dry, put toothpicks in the side (parallel to the ground), place onto glass of water. Only the bottom half of the seed should be in the water. The toothpicks keep the upper part outside of the water. Hope that helps. But if you don't buy organic, there's no point doing this!