Forcing flowers to bloom Bulbs: You can get crocuses, hyacinths, tulips and other perennials to blossom indoors during the winter.

November 10, 1996|By Ary Bruno | Ary Bruno,SPECIAL TO THE SUN

There is a wonderful way to add life and color to your home during the late winter months, even though the snow may be thick outside and spring weeks away. This easy process is called forcing flowers for indoor bloom.

Most spring blooming bulbs adapt well to forcing, but some are )) more reliable and less fussy than others. The best of the smaller bulbs are Dutch crocus and snow crocus, Siberian squill, wood hyacinths, anemone blandas and grape hyacinths. These can all be transplanted out into the flower bed in spring while their leaves are still green.

Tulips are also popular for winter forcing, and Triumph tulips are admirably suited for this. The species tulips, such as Tarda or Kaufmanniana tulips, also do well. Red Emperor is particularly splendid.

The best success will come from the smaller, multiflowered varieties, such as Tete-a-Tete, Ice Wings and Bellsong -- and, of course, the classic Paper White narcissus.

Hyacinths make delightful forced flowers with their beauty and fragrance. You can buy hyacinth vases or glasses and then watch the roots as they grow, but the glasses are not strictly necessary.

Forcing bulbs involves just a few simple steps that simulate the bulb's ideal natural environment.

First, plant the bulbs in pots in ordinary, well-drained potting soil, with a handful of compost and a tablespoon of bone meal thrown in. Plant the bulbs shoulder to shoulder in a 4-to-5-inch-deep pot, with the growing tip of the bulb even with the surface of the soil. (Daffodils will need a deeper pot, at least 6 inches deep.)

It is best not to plant more than one type of bulb in a pot, since each type requires a certain number of "chill hours," the time it must be chilled before it will break dormancy. A crocus will bloom with about eight weeks of chill time, but larger bulbs may require as much as 14.

The bulbs should make some root growth before being exposed to really cold temperatures, so, if possible, reduce the temperature slowly from about 60 degrees to 40 degrees over a two- or three-week period.

The idea is to provide an artificial winter by putting the potted bulbs in an unheated garage or on an enclosed porch where the temperature does not drop below zero. Keep them watered, as drying out can cause them to abort their flowers. And monitor the temperature. It's a good idea to cover the pots with plastic and mulch them thickly with newspapers or old blankets when the temperature is near zero.

Modern refrigerators are not the best place for chilling: They are usually not cold enough, only between 45 and 50 degrees. When bulbs are stored at too high a temperature the flower bud is often killed, though not the leaves. Second, modern refrigerators will dehydrate the soil rapidly unless the pots are enclosed in plastic bags. If you do this, remember to make some slits in the bags for ventilation and check moisture levels every few days.

Another method, which must be started somewhat earlier in the fall, is to pot up the bulbs as before, then find a sheltered but sunless place in your garden where you can set the pots into the ground, or at least on the ground, and heap them up with leaves or other mulch. Check on them from time to time so they do not dry out, and let nature do the rest. I am going to try it myself this winter.

When their chill hours have been satisfied, the plants will let you know it by putting forth a few pale shoots at the top of the bulb, and tiny white roots can be seen through the drainage hole in the bottom of the pot.

At the point when the shoots are 1 or 2 inches high, bring them into a cool but bright room -- no warmer than 60 degrees is best and 50 degrees is fine. Do not put them in direct sun for a few days, or they may burn. Turn the pots often, so that the plants don't all lean in one direction toward the light. A little soluble fertilizer or fish emulsion can be added once a week when you water.

The best situation is in a sunny, unheated, glassed-in porch where you can also supply two or three hours of supplemental lighting per day, or under strong grow-lights in a cool basement. In the latter case, the lights should be kept about 3 inches from the tops of the leaves. You may have to check them every day to adjust the height.

lTC In just 3 to 4 weeks you will be rewarded with lovely blooms!

If you want the flowers for a certain date or occasion, bulbs can sometimes be held for a short while prior to bloom by chilling them back to 40 degrees or so once they are well formed and the flower buds plump. This is often the practice for flower shows and in commercial greenhouses.

Pub Date: 11/10/96

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