The problem with the granulated fertilizers is that they must be absorbed by the soil first before being utilized by the plant. Also, many of the granulated fertilizers are salt based and the nitrates and may contributate to leeching into the ground water. We liquid organic fertilizers be used when possible.
They are more often than not sistemic, that is they are absorbed directly into the plant thereby over stepping the need to be absorbed by the soil first. They, as a rule, do not leech into the ground water and are not toxic or seen as a pollutents.