Answer: For annuals you can continue to fertilize until their life cycle is complete. For perennials, stop fertilizing about 6 weeks before cold temperatures/frost will hit to harden them off. Fertilizing promotes fresh tender growth which is susceptible to frost damage so that's why you want to discontinue for perennials. Annuals by definition are going to die anyway, so you can fertilize to keep them going as long as possible.
Q&A Library Searching Tips