Fertilizing Flowers

Nitrogen is the nutrient that most frequently limits plant growth. Unfortunately, nitrogen is the most difficult nutrient to manage. Soil tests for nitrogen are not dependable and nitrogen is easily leached from the soil. The challenge is to maintain adequate nitrogen levels to meet the plant requirements without damaging the plants or the environment.

Growth rate and foliage color are the primary guides for determining the need for additional fertilizer applications during the growing season. However, some general guidelines can be used. Nitrogen can be applied in a quick-release, water soluble form using a liquid or granular fertilizer or in a slow-release, granular form. Make applications of a quick-release fertilizer (such as 10-10-10), every four to eight weeks throughout the season at the rate of 1 pound per 100 square feet; liquid, water-soluble fertilizers should be applied about every two weeks.

With slow-release fertilizers, make only two applications. The first application should be incorporated into the bed just before planting, and the second should be broadcast over the bed midway through the growing season. The total seasonal application of slow-release fertilizer should not exceed 4 to 6 pounds of nitrogen per 1,000 square feet.

Consumer Horticulture | Quick Reference