Spring-flowering tulips produce vibrantly colored blooms from small bulbs. The tulips sprout early in the spring and generally last until summer, when hot weather and lack of water usually ends the lives of the blooms. Throughout the growth cycle, gardeners must observe planting and growing temperatures to ensure bright blooms.
Though tulips sprout in spring, the best time to plant the bulbs is during the late fall or early winter, generally between October and December. Plant them before the ground freezes completely or you will have trouble preparing and digging in the soil. Plant the bulbs 6 to 8 inches deep to protect them from the worst of winter weather. The low temperatures of winter put the bulbs into a dormant state. When the ground thaws and temperatures rise in spring, the tulips essentially wake up and bloom.
Tulips sprout best in cool to warm temperatures, which is why they sprout in spring. Tulip bulbs can withstand temperatures as low as -25 degrees Fahrenheit without suffering damage and will still be able to sprout in the spring. However, they do not tolerate heat well, and you will notice the flowers begin to wither and fade as soon as summer temperatures set in, generally in June or July. At this point, most gardeners trim off the dead flowers. Once the flowers are gone, leave the leaves in place for about six weeks or until they turn brown, especially if you plan to use the bulbs again.
Bulb Growth Information
Tulip bulbs will technically bloom for more than one year, but the blooms get smaller and duller each year. Therefore, many gardeners treat tulips as an annual plant, allowing them to bloom for only a season and then digging up and disposing of the bulbs so that they can purchase new ones in the following year. If you intend to try to bloom tulips again from the same bulbs, dig them up after all foliage has withered and turned yellow. Store them in a cool, dry place until planting in the fall.
Tulips grow well with at least four hours of direct sunlight daily, but will thrive best if they have protection from midday sun, which is extremely hot and can, mimic summer-like temperatures even during the spring. They do well under large shade trees since the tulips will be fading out by the time the trees produce their thickest foliage. Tulips grow best in well-draining soil. Add 2 to 3 inches of organic compost or manure during tilling in preparation for planting to give the plants an even better chance for a healthy bloom.