How to Fertilize Hyacinths

Purchase a fertilizer specifically intended for bulbs. Most garden centers that sell bulbs will carry a bulb-specific fertilizer. If you can't find this type of fertilizer, choose a balanced fertilizer that contains phosphorus.

Follow the package directions to find the amount of fertilizer you need to apply. This amount will vary between brands and types of fertilizer, but is based on the square footage of the area where your bulbs are planted -- for example, 1 lb. per 100 square feet. Water-soluble fertilizers need to be mixed into a specified amount of water. Granular fertilizers are sprinkled dry onto the soil.

Work the recommended amount of fertilizer into the soil before you plant your hyacinth bulbs in the fall. As you work in the fertilizer, also work in 1 cup of bonemeal per 5-square-foot area. Plant your bulbs to a depth of 5 inches.

Apply fertilizer again in late winter when you see the green foliage of your hyacinths begin to sprout. Apply water-soluble fertilizers with a watering can. Sprinkle granular fertilizers evenly over the area. To prevent burning the foliage, avoid getting the fertilizer on the leaves.

Water the area after you apply granular fertilizers to begin working them into the soil. You can also use a hand cultivar to work the grains into the soil if you are worried about children or pets getting into the fertilizer.