Fall is the perfect time for planting spring flowering bulbs (tulips, crocus, hyacinths, daffodils and others) and normally we are cool enough by mid-October to plant. The general rule of thumb is to plant these bulbs between October 15th and December 15th. So don't wait to long because these bulbs need a minimum of 12 weeks of under 45 degrees to bloom.
The key to success with bulbs is understanding what they are and how they grow. The bulb is actually a self-contained plant, the flower bud is already formed and just waiting for a dormant winter treatment, and the sides of the bulb are modified leaves. Tulips must totally regenerate a new bulb after flowering. To improve the bulbs ability to regenerate itself after flowering, the spent flower stalk needs to be removed, the plants fertilized with bulb food or a bloom booster fertilizer, and the foliage needs to remain green and growing as long as possible. These bulbs come from Holland in northern Europe, on about the same latitude as southern Canada. They grow in a much cooler climate and in very porous and sandy soil. With St. Louis turning hot in May, and our heavy clay soils, the bulb has a hard time regenerating. There are some things that you can do to improve your chances for multiple years of returning flowers: