Time to Plant Spring Blooming Bulbs

Posted by Hilda M. Morrill

November 5, 2010

Fall is the time to plant spring blooming bulbs and it could hardly be easier, says Sally Ferguson, director of the Netherlands Flower Bulb Information Center in Danby, Vt.

"Big bulbs including daffodils, tulips and hyacinths get planted 8 inches deep; small bulbs such as grape hyacinths, crocus and others are planted five inches deep. Plant in well-drained soil, cover up, water well and wait for spring. It's as simple as that."

Is it better to plant bulbs earlier or later in the fall? As a general rule, earlier is better, as long as the soil temperature has cooled sufficiently. One way to gauge "the right time" is to wait until autumn night-time temperatures drop below 50° F (10° C) for two consecutive weeks.

Once planted, bulbs need to establish strong root systems before the frosts of winter set in and the bulbs enter a new cycle in preparation for spring blooming. Planting six to eight weeks prior to hard frost is ideal, but bulbs manage to thrive with far less lead-time. Remember to plant bulbs in areas that drain well and water newly planted bulbs to help get those roots growing.

Is there a difference in bloom time between first year's bloom and later years'? Yes there is. Established perennial or naturalized bulbs tend to bloom 10 days to two weeks earlier in subsequent years than they did their first year because they're more settled and have a longer fall period for rooting. This is especially important to think about in fall when you are selecting bulb combinations to bloom together in spring, particularly if you're adding bulbs to an existing planting.

What if it's already early winter and I still haven't planted my bulbs? When best plans fail and you still haven't planted your bulbs by early winter, the answer is: Just plant the bulbs as soon as you can, even if you have to chip into the upper layer of soil. Bulbs are not dormant, they're alive; and they won't last much longer if left unplanted. If you can get them into the ground (either in pots or in the garden), chances are good that they'll grow. If you don't plant them soon, you may as well toss them.

A tip from Ms. Ferguson: If you know in advance you won't be able to plant until very late, throw small tarps or leaf piles over proposed planting areas to keep the soil warm and workable until you are ready to dig.

Expert gardeners have another late-season trick: They pot up unplanted bulbs for indoor forcing, or as container plants. With containers, you have the advantage of being able to control the initial soil temperature by adding your own soil. Choose the light potting soil mixes sold at all garden retailers. Move small containers to an unheated garage, old refrigerator or other cool, yet protected place. In spring, use the potted bulbs as outdoor accent plants or bring them indoors to enjoy.

Bulbs have a top and a bottom. The pointy end is generally the top. Of course with small bulbs, such as scilla, it's not always easy to tell. The other rule, not quite so catchy, is "basal plate down." The basal plate is the flat part on the bottom of the bulb from which the roots will sprout. Take a good look and it's not too hard to find this flat, usually darker basal plate. If you make a mistake, take heart. The bulbs will more than likely right themselves as they root. If in real doubt, plant the bulb on its side.

We thank Ms. Ferguson for her usual excellent advice regarding bulbs! For more information on fall planting, visit www.bulb.com.

Happy Gardening!