Fertilization
Fertilization is really not necessary at planting, but many people add bone meal around the bulbs to aid in root establishment. Fertilization is needed during the growing season to aid in the replenishment of the bulb. Fertilize once when the flower buds are beginning to open with a slow release fertilizer, or a general purpose fertilizer can be used when they show color, and again when the flowers have faded.
Bloom Life
To extend the length of blooms, do a little homework. With proper variety selection you can have color from late January through April, all with spring bulbs. Decide where you need color, and what else is growing there, and when it blooms. You wouldn’t want to plant hot pink tulips next to orange blooming azaleas, if they are in bloom at the same time. Color selection is important. Although your personal preferences are of the utmost importance, knowing which colors work together can help in the final outcome.