When it comes to keeping your annuals looking healthy and growing all season, we recommend fertilizing them every 3 to 4 weeks. Typically a liquid feed like Miracle Grow works well.
Just like people, plants have nutritional needs—and they too need more of some nutrients than they do of others.
Since annuals complete their life cycle in one season, they need more fertilizer than your perennials. Perennials have the advantage of starting over each season from a hardy root system. Can annuals live with the same amount of fertilizer as perennials? Sure, but to get the most out of them, it certainly helps to give annuals fertilizer more regularly throughout summer.