I have several clients who will have their 419 lawns topdressed this season. The programs for these clients have been previously set, but I cannot decide what theory of fertilization should be used following a topdressing event. We are talking about core aeration and then a mixture of sand/organic material or topsoil. The turf will normally be completely buried in material about 1/2 inch thick. The goal is to speed up the growth through the topdressing material. I have thought about these possible options: Ammonium Nitrate Potassium Nitrate Ammonium Sulfate Triple 19 I'm sure each of these would work, but what does the turf really need in this situation? We do not have a soil test to go by. The topdressing process is indeed stressful on the turf, so I would think Potassium would be a good thing. Also, we want the root system to strengthen, so Phophorous would also be good. That leads me to think that Triple 19 might be the best fit. Again, without a soil test I'm looking for a best fit option.