Early Fall is the ideal time to plant Spring flowering bulbs because it allows the root system to develop and establish before the ground freezes. Bulbs with a short dormancy, such as daffodils, crocus, and some of the very early Spring bulbs, should be planted in September or early October. Hyacinths and wood hyacinths can be planted at late as mid-Fall, and tulips can be planted successfully until the ground freezes.
Most bulbs prefer a light, well-drained soil that is rich in humus. Loose, friable soil beneath the bulb encourages good root growth and promotes drainage. Wet areas and poorly drained soils invite root rotting organisms to develop.
Bulbs should be planted at the required depth for each species, but, as a general rule should be planted 3 times deeper than the diameter of the bulb. In cold climates and where the soil is very light and sandy, bulbs should be planted deeper. In heavy clay soils they should be planted higher. Daffodil bulbs should be planted at a depth of 7″-8″; hyacinths 5″-6″; crocus 3″-4″; and tulips between 6″=12″. One tablespoon of bonemeal should be added to each hole or incorporated into the soil at the time of planting.
Generally bulbs are most effective when planted in clumps or drifts of at least 10 (large bulbs) or 25 (small bulbs) of a single variety and color. If the display is to be viewed from a distance, large naturalized colonies are effective.
Tulip displays should be replanted every year if the flowers are to be of a uniform size and height for a prominent display. Unlike other bulbs which increase by producing offsets annually, tulip bulbs split into smaller bulbs at maturity. These half-bulbs must then grow for 2 to 3 years until they reach flowering size.