Q. For the best spring flower display, when should I fertilize my tulip and daffodil bulbs?
A. To produce the maximum number of top-quality spring flowers, tulips and daffodils require care first in fall, at planting time, and then again in spring. At both of these times, gardeners can enrich the soil by adding a couple of inches of organic compost as well as synthetic fertilizer.
After planting the bulbs in fall, top-dress the bed with a balanced, 10-10-10 or 10-15-10 slow-release fertilizer. Lightly cultivate the soil to disperse the fertilizer, or water it in well. Apply fertilizer to the top of the soil instead of the planting hole to avoid burning the bulbs.
In spring, apply the same fertilizer when new green shoots appear. Continue to fertilize perennial bulbs twice a year at these times at no more than two pounds per 100 square feet of planting space at each application (or follow exact label directions). Although established bulbs are in a dormant state during summer, they will initiate new root growth in fall, thus utilizing the available fertilizer.
Fertilizer is only one of several ways to encourage bulbs to generate and store food for their spring flower display. Gardeners should also remember to let leaves and stems remain attached to bulbs this spring until they have lost their green color.
As long as they remain green, they are manufacturing carbohydrates that the bulbs will store and use as energy for next year’s growth.