There’s a sweet spot when it comes to planting spring-flowering bulbs. If you plant too early in your area, before frost arrives, the weather – and the soil – are too warm. Planted bulbs may sprout and even flower. By mid-December in many places the ground has started to freeze and become difficult to dig. November – neither too hot nor too cold – is prime bulb planting time in much of the country. Night temperatures are at or below freezing. During the day there’s a nip in the air, but working outdoors is not uncomfortable.
Spring-flowering bulbs needs a consistent period of cold (below 40 degrees F) in order to flower, usually 14 to 16 weeks. That’s not a problem in most areas of the U.S., however in warmer areas gardeners must chill these bulbs in a refrigerator for 10 to 12 weeks. Garden centers also sell pre-chilled bulbs.
If you’re wondering where to plant your bulbs, first look at your soil. It’s all about drainage. Many of our favorite spring-flowering bulbs come from regions without a lot of yearly rainfall, so they need soil that drains well. Don’t plant bulbs in soggy areas, particularly if the soil is wet in summer. Soil that stays wet will cause bulbs to rot. (Adding organic matter, be it well-rotted manure or compost, can help lighten wet soil.)
After soil, think sunlight. Most bulbs prefer mostly sunny to full sun conditions, but will flower with less. Since deciduous trees haven’t yet leafed out when bulbs start emerging in spring, there’s enough sunlight for them at that time, so you can plant in areas where later-blooming plants might suffer from lack of light. Bulbs flowering beneath deciduous trees also look gorgeous and wonderfully natural. However, they will never do well after their first year if planted under evergreens or the north-facing side of a building where the sun doesn’t reach.
Most bulbs do benefit from full sun after they’re done blooming. That’s because after bloom the leaves need sunlight to store energy for next year’s flowers. Don’t cut off any leaves until they’ve turned yellow or brown. For more information on how to take care of bulbs once they’ve finished blooming, check out this article, Aftercare for Spring-Flowering Bulbs:
Bulbs are usually planted in the soil at a depth two to three times the height of the bulb. Large bulbs are generally planted 6-8” deep and small bulbs 3-5” deep. The deeper the bulb is in the soil, the less susceptible it is to frost heaving or being dug up by animals. It’s always better to plant too deeply than too shallowly.
Can’t tell which end is up? The bottom of the bulb is the part with the roots, which will look a bit like dried-out grass. If in doubt, plant it sideways. But even if you plant the bulb upside down, it will know what to do. The flower stalk will instinctively grow upwards, reaching towards the light. It just might take a couple of extra days to get there.
After planting, give bulbs a good watering. Don’t skip this step. It signals to them that it’s time to start putting out new roots.
If you have a problem with animals eating your bulbs (either the bulb itself or the spring flowers or foliage), look for bulbs that don’t taste good to animals. These include daffodils, alliums, snowdrops, hyacinths, grape hyacinths, and glory-of-the-snow. Tulips bulbs and flowers are a delicacy to most wildlife (squirrels, deer, rabbits, rodents, chipmunks), as are lilies and crocus.
If you just can’t get your bulbs planted until December (or you find a bag you overlooked), and the ground is too hard to dig, you can try planting them in large pots that you then store (ideally away from light) in an unheated shed, garage, or basement. Be sure to water them after planting. If animals eating the bulbs could be a problem, cover the top of the pot with wire mesh. Check on them once in a while. In early March, bring the pot outside into the light and water the bulbs.
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