Yes, impatiens and other annual flowers are heavy feeders and need a complete fertilizer. I use Osmocote slow-release plant food because it will last all summer. Impatiens also like cool but not cold weather. If you are in a zone of very hot summers or in a cool summer climate with cold nights, the impatiens may be slow to flower. Take care not to overwater your impatiens or get their foliage wet when you water, as this plant is susceptible to a leaf fungus if kept too wet. Keep growing, Marianne Binetti