Why are bulbs planted in the fall?
Answer
Many bulbs need an extended cold period before they will flower. We encounter this when we force bulbs for early flowering indoors. Tulips and most daffodils will not bloom if the cooling period is insufficient. This prevents bulbs from flowering prematurely during warm spells in winter. Bulbs that produce flowers later in the season do not necessarily need fall planting.
Another reasons we plant bulbs in the fall is so they can get established. Generally, the fall air temperature is colder but soil temperature remains warmer. With soil temperatures of at least 40°F, the bulbs will root out and establish but not produce any leaves. Even if the ground is frozen, the bulb will still root out, just more slowly which is fine because it still has time. This rooting is important so that when spring comes the plant is ready to flower.
Planting in early March yields uncertain results. At that time of year the air tends to be warmer and the soil colder. So the bulbs root out more slowly than in the fall. By the time they root out and get established it could be April, after some of these bulbs typically flower. You are altering their growth patterns by planting them in the spring and the results are not predictable.
For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service
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