Our school, in Toronto, is planning a bulb sale fundraiser. We expect to end up with a large quantity of spring flowering bulbs for the students to plant. Should we plan to plant them this spring or wait until the fall to plant them?
Typically in Toronto, spring flowering bulbs are planted in the fall before the ground freezes. The optimal time is 6 weeks before the freeze which, in Toronto, is around the beginning of October. Spring flowering bulbs overwinter in the ground and this sustained period of dormancy is necessary to allow the bulbs time to establish roots and develop flowers before they begin to sprout in the spring. Most spring flowering bulbs are hardy, which means they do not need to be dug up and stored at the end of the flowering season, unlike tender summer flowering bulbs. Check that you order bulbs that are suited to growing in the Canadian Hardiness Zones 1-5 to be sure that they are hardy enough to leave in the ground year round.
Waiting until the ideal fall planting period increases the risk of loosing some, or all, of your bulbs to rot. Bulbs can also dry out and die if left unplanted. Try clearing the snow and digging holes. The general rule for hole depth is three times deeper than the diameter of the bulb. Plant the bulbs, pointy side up, in well drained, compost rich soil. Most bulbs prefer a sunny position. Adding bone meal to the soil at the base of the hole, and mixing it well in, will encourage root growth and deter rodents. Remember to cover the area with snow after planting.
If you are unable to dig into your frozen soil, scatter your bulbs over the snow cleared ground, cover with approximately 8 inches of soil, followed by mulch and then cover with a blanket of snow.
It is likely, if you are planting early or mid spring flowering varieties, that only leaves will sprout this season and no blooms. If you are planting late spring flowering bulbs, which have been stored in a cool place (ideally between 10-15 degrees celsius) you may get blooms, but they will likely be smaller than expected. These should come back next season at the normal size if growing conditions are optimal.
If you are unable to plant the bulbs outside immediately, you can bring them indoors as ‘forced bulbs’, (allowing them to flower inside after a cooling off period) or you can plant the bulbs in soil in plastic pots and overwinter the potted bulbs in an unheated garage, store room or cold frame. In the spring, place the pots into large containers, urns or planters outside and hopefully they will bloom.
Fertilizing your bulbs when they emerge in the spring, and after the blooms are finished, will help to keep them healthy. The flowering time for spring bulbs ranges from March until May, depending on the type and variety of bulb.