The Truth About Forcing Flower Bulbs for Winter Blooms

Forcing flower bulbs for winter bloom, which will help chase away the winter blues, and it only takes a bit of planning and time in the fall.
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Forcing flower bulbs for winter bloom, which will help chase away the winter blues, and it only takes a bit of planning and time in the fall. This guest post from Greg Coppa ran originally in the Sept/Oct 2017 issue of Horticulture.

A Pot of Prevention:
Fall-potted bulbs will bloom in time to ward off the winter blues

When Abby and I married I promised that I would always have plenty of fresh flowers in the house, cut from the seasonal profusion in the yard or in pots carefully tended to throughout the winter.

overwinter containers

Daffodils cheerfully bloom on a window sill in the gray months of winter.

It has been an easy pledge to honor, pretty much, what with a succession of naturalized daffodils, irises, assorted lilies, roses and whatever annuals we are featuring in any given year. Here in southern New England, the last of the chrysanthemums leave in November and the first snowdrops arrive at the Ides of March. Christmas-themed plants dominate December; the challenge is finding petal power to chase away the January and February blues. Here’s where spring bulbs come in, forced to bloom in pots.

Delightful daffodils, heady hyacinths, tantalizing tulips, gorgeous grape hyacinths and comely crocuses—nothing is more cheerful on a cold, gray, raining and sleeting day than a pot of any of these in bloom on the coffee table or at the window. It’s easy to do, as long as you choose varieties wisely and have a plan for bringing them along.

Bulb Forcing Made Simple

When it comes to selecting bulbs of all types, size generally does matter—it determines

Sorting bulbs before fall planting in pots for winter bloom.

Sorting bulbs before fall planting in pots for winter bloom.

whether you have abundant blooms or none at all. Around the middle of September, choose the plumpest bulbs that you have purchased. (Bulbs for forcing can also be dug from your garden in early summer after their foliage has browned and shriveled. Dug bulbs should be hung in a plastic mesh bag, the type that onions and oranges are sold in, in a cool dry place.) Carefully peel off any small bulbils and put these runts in that corner of your garden reserved for bringing along future specimens of all kinds.

Stick With One Variety

Spring bulbs are just peeking through the soil in a clay pot.

Spring bulbs are just peeking through the soil in a clay pot.

Usually, you are better off planting one variety per pot, because not all varieties develop at the same rate. Mixed pots can work, but you must experiment with them a bit first. With trial and error, you should be able to synchronize some small, bright yellow daffodils with deep purple grape hyacinths, for example. Sometimes, though, it just doesn’t work out. I always liked the idea of having three different colored hyacinths at peak bloom in the same pot, but I never found the right combination to make that happen. Play with crocuses or tulips, which both offer a wide spectrum of possibilities if you want a floral rainbow in one container.

Be aware that some varieties of bulbs are prone to producing leggy stems and they may have to be supported with green stakes and florist wire. You can bypass this problem if you choose naturally short varieties of daffs like ‘Tete a Tete’, ‘Little Gem’ (which resembles ‘King Alfred’ in structure but stands only four or five inches tall) or ‘Minnow’, a bit taller than ‘Little Gem’ and also somewhat fragrant.

Pots you saved from spring plant purchases come in handy now. Place groups of your chosen bulbs in them pointed side up. Have a one-inch soil base for them and cover them with at least two inches more. A little bone meal mixed in with your growing medium won’t hurt. Water generously so the bulbs get the message right away that they are to begin sending out their roots.

Place your pots in your declining vegetable garden or flower beds, about three inches below ground level, covering them with soil and maybe even a layer of mulched leaves. Mark where they are and consider putting a protective layer of chicken wire over your cache to protect the bulbs from the usual marauders.

After 10 to 12 weeks you may dig the pots up and bring them to a cool, but not cold, place—like a garage or cellar. I do this around December 15, before the ground hardens in my area. Keep the contents damp. To begin the awakening process, simply bring a pot into your home. In a short time, you will see greenery projecting through the surface of your growing medium. You can hasten this process a bit by putting the pot in a warm boiler room or laundry room until the green tips emerge about a half of an inch. While it may be tempting to leave the pot in a warm place for accelerated growth, don’t do it. This is how bulbous plants get too leggy, and it may also shorten their total blooming period.

Once you see that the plant has broken dormancy, put it in a place that will cheer you and your guests. Some occasional sun through a window may help the bulb to revitalize to a degree for the future if you choose to keep it. Personally, I never throw a bulb away.

You may prolong the blooms by putting the pot back in a cool location, like a garage or less heated room, while you take a three-day weekend vacation, for example. It is all about temperature. A warm environment speeds growth and development, a cool one retards it.

Bring more pots from your cool staging area as you need them, following the process just mentioned. And don’t forget to give away a few, too, to neighbors and friends.

When the show’s over, I usually put the spent plants back in the ground outside in a sheltered, sunny location and let them go through the normal cycle for naturalized bulbs. I don’t attempt to re-pot them, though, for the following year. Instead, I plant them out in the yard somewhere so that they will fully recover their vitality.

Squirreling away spring bulbs does take a little effort. But there will come that miserable day that proves it worthwhile.

Greg Coppa gardens and writes in Rhode Island. You can subscribe to Horticulture here.