How often do you recommend fertilizing?
I suggest fertilizing container plants each four or five days. Early in the season, switch forward and backward between a nitrogen compost and one that is lower in nitrogen however higher in phosphorus and potassium to help blossoms—with the exception of plants you're developing for their foliage. Once the plants are in blossom generation mode, by mid-July, use just the flower booster, assuming the plants are the size you want. Never fertilize when the soil is dry; it can burn some plants.