So, you bought a few packs of spring-flowering bulbs (tulips, daffodils, crocuses, hyacinths, etc.) last fall, intending to plant them right away. Except it’s now winter and it’s apparently too late to plant them, what with the ground is frozen or covered with snow. It looks like you missed the boat. So, can you keep bulbs over the winter and plant them in the garden next spring?
In general, that’s not a good idea. Most of these bulbs will not bloom unless they undergo a long, cold winter. But there are several other options:
The most logical thing to do with fall bulbs is still to plant them outdoors, even though it’s later than normal.
If the soil is not yet frozen (that will depend on your local climate), there is no problem in planting tulip bulbs, narcissus, crocus, etc. as late as December or even January.
If there is snow on the ground, sometimes you can just brush it away before planting and still dig.
If the ground is frozen, but only on the surface, it’s easy enough to break through the frozen crust thus formed. Then just plant as you usually would, digging a hole three times deeper than the bulb is high (for tulips, a depth of 1 foot/30 cm is preferable) in rich, well-drained soil somewhere that receives spring sun. There is even an advantage to planting a bit late: often the surface soil refreezes quickly after planting, keeping the bulbs safe from squirrels.
If crunching through a crust of frozen soil is not your idea of easy gardening, here’s an equally effective, but faster method.
First remove the snow, if there is any, then set the bulbs on the ground. Now, here’s the neat part: you don’t really have to dig a hole at all. Just cover them with a bag or two of garden soil or potting soil. Again, strive for a depth three times the height of the bulb. The warmth of the fresh soil will thaw the ground below, allowing the bulbs to root well… and they’ll be buried deeply enough that they won’t freeze until they’ve rooted in, which is what you want.
I’ve used the “no-dig planting” method during a January thaw and had great success.
This is the ideal method for planting bulbs where there is root competition too, such as in a wooded spot, even when the soil isn’t frozen.
Too Late, the Soil is Frozen Solid
The two previous methods only succeed when the soil is not frozen or only frozen on the surface. If the ground is frozen so deeply that a shovel can’t penetrate it, then it really is too late to plant your bulbs outside this season. But there are still other possibilities.
Forcing to the Rescue
You can also force bulbs indoors for spring bloom in pots and in fact, this is the most logical solution to apply when the ground is thoroughly frozen.
Just pot them up and water well. Seal the pot inside a plastic bag (to prevent evaporation, as you’ll want the roots to remain moist at all times) and place it in a refrigerator, a heated garage or a cold room. It takes about 13 to 14 weeks (three and a half months) of cold for the bulbs to get ready to bloom (a bit less for hyacinths), then in late March or early April, set the potted bulbs on a bright windowsill… and fill your home with blooms!
You will find more information about forcing in the article Forcing Bulbs without Twisting Arms.
It is also possible to store the bulbs dry in a cold spot over the winter, thus giving them the cold period they require for blooming… before you plant them. This technique is called “pre-chilling” and is commonly used to make tulips, hyacinths, narcissus, crocus, etc. flower in regions where they normally wouldn’t bloom because the winter isn’t cold enough for them (spring bulbs are cold climate plants: without a cold winter, they won’t flower). If you see tulips or hyacinths blooming at Disneyworld, on the French Riviera or in Australia, their bulbs were probably pre-chilled.
For pre-chilling, store your bulbs bare (i.e. unplanted) in the refrigerator, a barely heated garage or in a cold room over the winter. The temperature should remain between 34˚ and 40˚F (1˚ and 5˚C) at all times. They can be stored loose in an open box or container or placed in a mesh bag, a paper bag or a nylon stocking, but never inside a plastic bag (under plastic, there is too much risk of condensation and during pre-chilling the bulbs must remain dry).
Now, where spring comes around, plant the pre-chilled bulbs outdoors as soon as possible, while the soil is still cool too cold. There is then a very good chance that not only will they bloom beautifully this first spring, but that’ll they adapt and come back to flower again and again for many springs to come… that is, if you live in a cool to cold winter area. (In warm-winter climates, such bulbs will not come back and are best treated as annuals.)
So, to resume the situation: the very best way to ensure that spring-flowering bulbs bloom beautifully not only the following spring but also perennialize well still remains planting them outdoors in the autumn according to the traditional method. But at least you now know what to do if you miss that opportunity!