actually I wouldn't spray the plant unless it was with a good foliar spray concentrate. As far as watering goes it goes like this. The upper 1/3 of the roots need oxygen the most, the middle 1/3 needs oxygen and water more balanced, and the bottom section of the roots take in water and nutrients the most. That's why most people just let the bottom section of their roots hang in the water/nutrient mixture. The air stone outputs the oxygen the plants roots need and it rises to where it needs to be taken in.