What is the proper way to fertilize bulbs with granular organic fertilizer? If I sprinkle it on top of the soil as the bulbs are emerging in the spring, does the fertilizer ever work its way down to the roots? If so, how long until it reaches them?
Spring-blooming bulbs, though dormant throughout the summer months, will have a semi-awakening in the fall and commence root growth until the ground freezes. On some, like the grape hyacinth, you may even get leaves; this of course makes it easier to find the bulb patch. So, as the days cool off in the fall, this would be a good time for your first light application of fertilizer. A liquid bulb fertilizer may be used or a low nitrogen granular. The granular, however, will need to be lightly scratched into the soil and watered very well in order for the nutrients to reach the bulbs. This step allows you to skip an early spring application. Directly after bloom—when you’re removing the flower head and stems (making sure to leave the leaves until they are brown)—is the next time that you may want to fertilize your bulbs before they go back into their summer dormancy.