: Espoma RP28 Rock Phosphate, 28Pound: Garden ...
Very fair price and Prime shipping. This bag will last many seasons. 2015 A good rule to remember when considering NPK needs for plants is: UP nitrogen (N) for top growth, DOWN phosphorus (P) for root growth ALL AROUND potassium (K) for all around health. So in this case phosphate (P) is for establishing root growth in my seedlings.