Many types of flowers grow from bulbs, including tulips, lilies, and phlox, as well as foods like garlic and onions. Hardiness zones are numbered 1 through 11, with 1 as the coldest and 11 the warmest. Zones indicate average minimum winter temperatures to give an idea of which plants will do well in a particular region. Bulbs take a long time to flower, so they must be planted in the fall for spring blooms. Since most bulbs must winter in the ground, you must know which bulbs to plant according to your zone.
Consider amaryllis varieties if you live in a very cold region, as these are best suited to Zones 1 and 2. Plant the bulbs in early September, which should give the bulbs enough time to get established before the ground freezes. A month after planting, lay a few inches of mulch over the bulbs. Mulch will help keep the bulbs from freezing during the coldest winter months.
Choose from a large variety of flowers if you live in Zones 3 through 8. Most types of lilies, narcissus, tulips, daffodils, and phlox do well in these zones. Alliums like onions, shallots, and garlic also thrive in zones 3 through 8. In Zone 3, most bulbs should go into the ground in early to mid-September. In Zones 4 and 5, you should plant your bulbs in late September or early October. Mid-October is the best time for Zone 6, and bulbs in Zones 7 and 8 should go into the ground in November or December.
Chill bulbs in the refrigerator for 8 to 10 weeks before planting if you live in Zones 8 to 11. Chilling is a way of forcing bulbs by creating a false dormant period. Put the bulbs in the crisper drawer away from fruits and vegetables. Exposure to ethylene gas emitted by fruits and vegetables can kill the developing buds.
Plant warm weather bulbs if you live in Zones 9 through 11. Calla lilies, day lilies, and many types of tulips and amaryllis do well in warm regions. In Zones 9 through 11, bulbs can go into the ground in December or even January for spring blooms.
Bury bulbs at a depth that is twice the height of the bulb with the root end facing downward. Plant them in well-drained soil in a place that gets full to partial sun, depending on the plant's requirements. Keep the soil moist throughout the winter and while the bulbs are in bloom.