Last updated on December 2nd, 2011
We who garden indoors get to enjoy each year the colors and scents of spring not once, not twice, but many times. That’s because we plant in October a series of hardy bulbs. True, such bulbs require more effort to grow than their tender tropical relatives. But how they reward us for every trip to the cold cellar or garage! Graceful snowdrops open their white, nodding bells while the Christmas tree still stands…blue hyacinths perfume the January dining room…crimson tulips accompany fireside dreams in late winter. You can enjoy this portrait of blossoming beauty, too.
Just as they do in nature, hardy bulbs require a cold and dark period in which to develop their roots. But every flower that emerges is already formed within the bulb you plant. All you need do is provide suitable growing conditions for the blossoms which nature has already determined.
Now, you might be wondering if these bulbs can be left in paper bags, refrigerated, and then potted up later. Yes, they can. But in my experience the blooms are sturdier and more reliable when the bulbs are potted before they go into cold-storage.
A soil mixture on the sandy side is preferable not only for flowering but for the complete maturity of the bulbs, so that they will be worth planting in the garden next fall. I make my own, well-draining peat-free mix from two parts garden soil, one part leafmold, and two parts sand or perlite. You can use a commercial formula, too, but it’s a good idea to amend it with extra perlite (one heaping tablespoonful to every six-inch pan will improve drainage).
I plant these hardy bulbs in shallow pans, not pots, that are wide enough to support three hyacinths or daffodils, and five or six tulips per six-inch pan. To provide good aeration to roots, I always use pans made of unglazed clay. Tulips bulbs are planted so that their tips are just below the surface of the soil (which, as always, is one inch below the rim of the pot), narcissus bulbs level with the soil surface, and hyacinths barely peeking out. Crocuses, snowdrops, puschkinia and iris reticulata are all planted one inch deep.
Next comes the hard part: finding cold, dark quarters where the bulbs can make their roots. In my New York City days I placed the pans on the lowest shelf of my refrigerator. Today, I set them in the coldest room of my root cellar. A friend keeps his potted bulbs in an unheated garage. To keep the bulbs from freezing, he sets the pans in a cardboard box, with a thick layer of insulating salt-hay spread between and on top of the pans. Anyway, let your imagation be your guide to finding a dark place that stays between 35-45 degrees from October through January.
Hardy bulbs that I have successfully forced over a number of years, along with their required weeks of cold storage, include:
Tulip, Dutch ‘Queen of the Night’: 12 weeks
Tulip, Dutch ‘Apricot Beauty’: 12 weeks
Tulip, Dutch ‘Red Revival’: 12 weeks
Tulip, species, ‘Dasystemon Tarda’: 8 weeks
Snowdrops (both single and double varieties): 8 weeks
Hyacinth, French-Roman: 6 weeks
Hyacinth, Dutch ‘Blue Jacket’ (and others): 12 weeks
Crocus: 10 weeks
Narcissus ‘Erlicheer’: 10 weeks
Narcissus ‘Golden Dawn’: 10 weeks
Narcissus ‘Actea’: 12 weeks
Narcissus ‘Little Gem’: 12 weeks
Iris Reticulata: 8 weeks
Puschkinia: 12 weeks
As you can see from the schedule above, the earlier you pot your bulbs, the sooner you can enjoy their flowers. As a rule, I make all of my plantings the first week in October. Then, starting on November 1, the transfer from cold storage to warmth and light begins, when the French-Roman hyacinths are brought to the window garden. These bloom in time for Thanksgiving. Because bulbs can remain in cold storage beyond their required time, you can have at your whim a lengthy parade of color that continues week-after-week and month-after-month as pans are brought upstairs.
Water is necessary throughout the cold duration. Soak the pans immediately after planting, and thereafter at the first sign of dryness. In general, cellar-stored bulbs require water about once each week; refrigerator residents only once each month.
A light and cool location is the next resting place, then as top growth develops, more light and a higher temperature (50-60 degrees). When flower buds show, I give them full sun and warmth. But not too much warmth — 65 degrees is the maximum temperature if flowers are to last for a potential three weeks or longer.
To get the biggest bang from my hardy-bulb buck, I continue to care for the bulbs even after their flowers have faded. The dead flowers are cut off, but the plants are allowed to remain in an east or west window. I keep them watered and fed until their yellowed foliage signals dormancy. At this time the bulbs are removed from their pans, and saved in paper bags filled with sawdust. There they stay until the fall, when I give them a permanent position in the outdoor garden. In two year’s time they bloom as if they had never known the inside of my house.
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