Bulb Planting Depths

In general, spring-blooming flower bulbs should be planted at three times the height of the bulb. For instance, if the bulb is one-inch tall, plant it three inches deep.

Here are general measurements for how deep to plant common bulbs:Crocus: 2 to 3 inches deep

Grape hyacinth (Muscari): 3 to 4 inches deep

Dutch iris: 5 inches deep

Dutch hyacinth: 6 inches deep

Fritillaria imperialis: 8 inches deep

Tulips, daffodils: 8 inches deep; if the bulbs are small, as shallow as 5 inches will suffice

Many bulbs have contractile roots, by which they will pull themselves deeper if they are planted too shallowly—hyacinths, daffodils, some alliums, lilies, crocus and gladiolas among them.

Image courtesy Bulb.com