I have a tendency to agree with Caroline but with no scientific proof. Most fertilizers require time to breakdown into nutrients the plants can use. Nutrients do leach down into the soil as the rains soak the soil. I think it is more important to stay away from the crown area and force the roots to seek the farther out nutrients since they do not grow any more than necessary. Compost and other organic fertilizers are already broken down to feed the plants so that would be a different story. For me, MG bloom booster with some additional epsom salt has proven to be ideal for all flowering plants. At $5 per pound though, it would be expensive on a large scale. It is the trace minerals which do the most good with plants.
