Tulips, like all bulbs, make food for themselves after blooming. Each bulb must make and store enough food for itself within a few short weeks before going dormant for much of the year. This postbloom period is critical for this cycle. If an impatient gardener cuts the stems prematurely, the bulb may essentially starve to death and not emerge the next year.
After your tulips have lost their luster, it is good practice to remove the petals so that they do not set seeds. Allowing tulips, and all bulbs, to set seeds reduces the bulb growth of the individual plant and hinders the following year's bloom. Leave the foliage above ground for at least six weeks to ensure proper food production and storage. Once the foliage has withered and turned brown, it can be removed, as this indicates the cycle is complete.
After your tulips are finished for the season, you can safely dig and divide them if needed. If you notice poor performance after a few years, including blossoms that are smaller or fewer than usual, it is time to divide the bulbs. Plant the divided bulbs as soon as possible. If you prefer not to replant until fall, shake off the soil and allow your tulip bulbs to air-dry. Then place them in a ventilated bag or box and store the bulbs in a cool, dry and dark area.
Tulips can provide many years of color in your garden. Plant new ones in the fall and water them in. Give them a good watering in the spring as well to get off to a good start. A feeding of bulb fertilizer as soon as you see green emerge is good practice too. With plenty of sun, and a little help from the gardener, tulips can be one of the easiest plants to grow.