Bulbs do best in a sandy, clay loam. In heavier soils, they should be planted 1 to 2 inches higher. For fertilizer to be effective, it must be present in the vicinity of the roots. Excavate the bed to the bulbs' planting depth. Apply the fertilizer and soil amendments at this level, and spade or rototill the soil to a depth of 3 or 4 inches.
Aeration is the most important aspect of soil preparation.
Before the soil is shoveled back into the bed, mix it with some type of organic matter. Space the bulbs as desired, refill the bed and water to settle the soil around the bulbs. The flower bud and the food necessary to produce the flower are present inside a bulb when it is planted. Fertilizer is applied to make larger bulbs the following year. Apply phosphorus fertilizer at planting time so it is available to the roots, because it does not translocate in the soil.