Spring bulbs bloom in the spring. The most common of these are crocuses, tulips and daffodils. The term bulb has become a catchall for all flowers with fleshy underground root stems, including true bulbs, corms, rhizomes and tubers. Whatever type of spring bulbs you have, they are typically planted in the fall in USDA hardiness zones 3 to 9. While it is not ideal, they can be planted in the summer if necessary.
Wait until the end of summer, as close as possible to the last day of the season, usually September 21 or 22. By planting earlier in the summer, you run the risk of the bulbs beginning to grow green foliage, thereby using up valuable nutrients needed for spring flowering. As a result, the bulbs may not bloom the first spring after they are planted. This risk is greater in the warmer planting zones.
Choose a planting site in full sun or around deciduous trees whose branches will be bare when the flowers bloom. Keep in mind that the bulbs will still need partial sun during the summer months to absorb light and turn it into energy.
Turn over the top 12 inches of your planting bed and mix in 2 to 3 inches of organic matter such as compost or peat moss. This will enrich the soil and improve drainage.
Plant the bulbs. Corms and true bulbs generally are planted to a depth that is 2 to 3 times the width of the bulbs, with the tips facing up. Tubers and rhizomes are planted closer to the surface of the soil. Each variety is different, so be sure to follow the planting guidelines specific to your bulbs. The eyes or necks should be on top, and the fleshy roots at the bottom. For all spring bulbs, spacing is always specific to the plant but is roughly the same as the size of its mature spread.
Backfill the soil and pack it down lightly with your hands. Then water the planting site well. For bulbs planted closer to the surface, an inch of water will suffice. Bulbs planted deep need 2 or more inches of water for it to reach them.