Fertilizing blooming flowers will make them healthy and long-lasting. Fertilizer is made of three components--nitrogen, phosphorus and potassium. Nitrogen promotes green growth, phosphorus strengthens the flowers and encourages root development and potassium builds strong and healthy plants. Fertilizers also contain calcium, which encourages young roots to grow, sulfur which maintains the dark green color and magnesium which encourages the formation of seeds.
Wait until spring to fertilize established flower beds. Many flowers don't need to be fed in the winter, so you should wait until the threat of freeze passes. Spring feeding will help flowers as they enter their growing season.
Remove existing mulch from the base of the flowers with a rake before you add fertilizer. This allows the fertilizer to get into the roots.
Choose a fertilizer with a lot of phosphorus. This will encourage big, bright blooms, whereas extra nitrogen makes them turn vegetative. Look for one with a ratio of 5-10-5 which means it has 5 percent nitrogen, 10 percent phosphorus and 5 percent potassium.
Select a time release fertilizer over a liquid fertilizer for low maintenance feeding. It will provide continued nourishment to blooming flowers. Apply it every six months by spreading it around the base of blooming flowers.
Sprinkle dry fertilizer around the base of blooming flowers every two to three weeks. If using liquid fertilizer, add it to the watering can as per the manufacturer's instructions. Use it whenever you feed the roots.