Fertilizer is food! If you want petunias bursting with blooms, you have to feed them.
Petunias planted in landscape beds don’t have to be fed as often because their roots can spread out to find the nutrients they need in the soil. To get petunias in beds off to a good start at the time of planting, use Marcum’s Nursery Redbud Compost and a slow release fertilizer, such as Marcum’s Nursery Flower Food (14-14-14) or ferti-lome® Premium Bedding Plant Food (7-22-8), then feed them on 30 day intervals.
Petunias in pots and hanging baskets require more food to bloom repeatedly. For example, the hanging baskets in our greenhouses get a low dose of balanced fertilizer each day; however, you don’t have to fertilize daily to produce beautiful blooms. Many fertilizers only need to be used on 7-14 day intervals. Some water soluble fertilizer options include ferti-lome® All Purpose Water Soluble Plant Food (20-20-20), ferti-lome® Blooming & Rooting Soluble Plant Food (9-58-8) and Marcum’s Nursery Bloom Max™ (10-55-10). A couple of liquid organic options are ferti-lome® Fish Emulsion Fertilizer (5-1-1) and Fox Farm® Big Bloom® Liquid Plant Food (0-0.5-0.7). Be sure to check your fertilizer label for application instructions.