Of all types of gardening, none gives more certain results nor greater returns in proportion to the amount of time and attention required than that of forcing bulbs for winter bloom indoors.
I have put the term “forcing” in quotes to emphasize at the start that while it is still generally used, it does not apply. It is distinctly misleading and scares many amateur gardeners away from winter garden pleasures they might easily enjoy.
With very few exceptions, hardy bulbs grown for winter and early spring bloom are not forced at all.
They are merely planted early outdoors, where they remain for a month or more so that nature can take its usual course; they should occupy space on a window sill or table only while they are in bud and bloom.
With a proper selection of types and varieties, bulbs may add colorful cheer from Christmas to Easter, and in most cases, they may be used afterward for planting in the garden to provide spring color for years to come.
Many garden beauty spots originated in pots that first graced greenhouse benches or window sills.
But before rolling up our sleeves and plunging into the mechanics of growing (rather than “forcing”) bulbs indoors, let’s look at the remarkable range of beauty that bulbs, tubers, and corms place at our disposal.
Hardy Bulbs Group
The first thing to consider in indoor growing bulbs is that there are two distinct groups —the hardy and the tender.
The first category includes those that we usually term spring-flowering bulbs: daffodils, tulips, hyacinths, crocuses, muscari, and so on.
In general, these come from cold or moderate climates. To do their best indoors and out, they must be grown at a cool to very moderate temperature.
Tender Bulbs Group
The second group—the tender bulbs, flowering, according to their kinds, at different seasons of the year—are residents of warmer climes.
Most of these require considerably more heat over a much longer period than the spring bulbs do. This group includes Amaryllis, calla-lily, caladium, oxalis, veltheimia, gloriosa-lily, and freesia.
Difference of Hardy and Tender Bulbs
The chief difference in the culture indoors of the hardy and the tender bulbs is that the former requires several weeks at low or even freezing temperatures before being brought into the greenhouse or living room, while the latter does not.
This, however, is a distinct advantage in favor of the hardy bulbs, as they may be kept out of sight and out of mind within a brief period of the time they are wanted for flowering indoors.
It is almost like having a supply of frozen foods on tap to be used as wanted. All the work of potting and storing them can be done at one time—as described later in this article. They can then be brought in for blooming as desired.
While most varieties of the big three—tulips, daffodils, and hyacinths—may be grown indoors, some respond to this treatment better than others.
A number of our favorites, among the many we have tried, are:
Tulips
Easiest of all, and earliest to flower, is the single garlic, which may be in bloom by Christmas or New Year’s. A few of these are deliciously fragrant, which adds to their charm.
We particularly like Brilliant Star, vermilion, earliest, Df. Wet, orange, and gold, most fragrant; and Rising Sun, pure yellow.
There are double earlies, too, such as Marechal Niel, orange-yellow, and Peach Blossom, which lasts exceptionally long.
Many of the later flowering tulips (cottage and Darwin) may be flowered indoors successfully, but they require a longer time and bigger and deeper containers for soil.
William Copeland, lavender is an exception to this rule and goes nicely with the single earlies, among which this color is lacking.
Tea Rose, light yellow, and Ellen Wilmott, yellow, are fragrant. The comparatively new variety Rosy Wings, salmon-rose, is especially charming when pot-grown.
Daffodils
Most daffodils may be readily flowered indoors, but the beginner will do well to use small-flowered sorts such as February Gold—an old-timer but still our favorite—and the multi-blossomed poetas varieties like Cheerfulness, Golden Cheerfulness (both fragrant) and Geranium, before attempting the tall-growing giant trumpet and short cup varieties.
Others that give a pleasing, artistic effect to a window sill are Golden Scepter, yellow; Thalia and Moonshine, creamy-white.
Hyacinths
Hyacinths are proverbially the easiest bulbs to bloom indoors, requiring merely a bowlful of pebbles kept moist by occasional watering.
Better and much longer-lasting results will be had—with very little more effort in the end—by growing them in pots of soil.
We use medium-sized (and considerably less expensive) bulbs that produce small, graceful spikes of bloom in preference to the giant “forcing” size, which makes clublike spikes that are even more artificial-looking than the plastic blossoms seen in the show windows of florists in our large cities.
The hyacinths usually seen are of hard, bright colors in reds, purples, blues, and carmine-pink.
We like the pastel shades found in such varieties as the City of Haarlem, primrose-yellow; Myosotis, porcelain-blue; Carnegie, cream-white; and Princess Margaret, an enchanting soft pink.
Little Gems
Little home decoration gems are very easily grown but not often seen, including many of the smaller spring-flowering bulbs. They provide bright blooms for sunny window sills, are inexpensive, and require little work.
Grape-hyacinths (muscari) take up little room and strike a contrasting note of pure blue to go with golden daffodils.
Our favorite variety is the Early Giant (Muscari armeniacum). The feather-hyacinth (M. plumosum) blooms later; its much-lacerated spikes are orchid-lavender and last almost unbelievably long if kept cool. It is always a surefire conversation piece.
Crocus, Snowdrop, Glory-of-the-Snow and Scilla
Crocuses, snowdrops (Galanthus), glory-of-the-snow (chionodoxa), and scillas all flower so early in the garden that they are seldom “forced,” but a potful or two of each will provide January or February bloom indoors that is welcome cheer when one is waiting for spring to arrive.
They are particularly fine for a cold room or an unheated sun porch where the temperature remains too low to encourage most other bulbs to bloom indoors.
The tender bulbs for growing indoors include tazetta narcissus— paper white and Soleil d’Or— French Roman hyacinths, anemones, ranunculus, and freesia. All of these bloom by Christmas or even earlier.
Many other bulbs may be grown indoors—Callas, gloxinias, and veltheimia, for instance—but these are treated as house plants rather than as “forced” bulbs and we are not here concerned with them.
Growing Spring Flowering Bulbs Indoors
Even on the first trial, it is not difficult to succeed with growing spring flowering bulbs indoors.
With few exceptions, they do not tolerate high temperatures, even after they are brought in. No special soil or growing technique is required.
Here is what you do.
1. Procure a quantity of good garden soil. A bushel will serve two or three dozen pots of assorted sizes. Add enough sand or sandy soil to make it brittle if the soil is heavy. Add peat moss, about one-third in bulk, and organic fertilizer. Mix thoroughly and screen if necessary to remove lumps and/or stones. Moisten moderately and store in a box or ash can.
2. Get a supply of plant labels, preferably 12″ inches long, and coarse peat moss, compost, or lumps of charcoal. Long labels are desirable as they can be read even when pots are covered several inches deep in the cold frame. Coarse peat moss, compost, or charcoal covers drainage holes in pots and prevents soil from washing out.
3. Procure a sufficient number of pots to hold bulbs. Shallow pots— bulb pans or azalea pots—are best, as they are less likely to tip over and they dry out less rapidly.
4. Order bulbs early and pot them up as soon as they are received. Except for hyacinths, use top-sized bulbs for blooming indoors.
5. If a cold frame is unavailable, prepare a temporary frame of 6-inch boards to place the pots, or a trench 10″ to 12″ inches deep may be dug in any convenient, well-drained location.
Potting
Place a layer of coarse material (or shards of broken pots) over the hole in the bottom of each pot and fill about two-thirds to three-quarters full with prepared soil.
Then, set bulbs in place, firming well into the soil. They can go almost shoulder to shoulder but should not quite touch.
Fill in soil, firming well around bulbs, to within a half-inch of the top for small pots and somewhat more for larger ones.
Place pots in a pan or tray with 2″ inches or more of water and allow this to soak up until the surface soil is moist. If new posts are being used, soak these thoroughly before potting.
Rooting
The pots, placed in the frame or trench, are packed in moist peat moss and covered with the same to a depth of 2″ inches or so. (Soil may be used for covering, but if it freezes, getting them out is much more difficult.)
On the approach of freezing weather, a sheet of plastic film may be spread over the surface, and more peat moss or soil and dry leaves may be spread over this.
Where hard freezing is expected, a glass sash (if available) or boards may be used as a further covering. The object is to keep the pots cool, even to freezing, and still easy to get out when they want.
Bringing In
The first pots of each variety may be brought indoors as soon as roots have developed and top growth shows indications of starting up. The time required will vary with the kind of bulb and the variety.
It is desirable to have the new growth develop slowly at first, so pots may be placed in a cool cellar or sun porch with a temperature of 40° to 60° degrees Fahrenheit. As tops turn green and growth increases, give them full light and a slightly higher temperature.
At this stage, giving each pot an individual saucer is well, as they will vary widely in water required.
Give as much sunshine as possible, but avoid heating pipes or radiators. If the latter cannot be done, a sheet or two of thick insulating material placed between the pots and the heat source will help.
Temperature
Flowers last much longer if pots are removed to a cool temperature of 35° to 45° Fahrenheit at night.
After the blooms fade, cut them off and water pots thoroughly. Then, place them in a frost-proof frame or another cool place to allow foliage to mature naturally.
Transferred to the garden in early spring, bulbs will usually re-establish themselves and flower again a year or two later —thus allowing you. In this instance, to cat your cake and have it too.
44659 by F. F. Rockwell