Start bulbs now for winter bloom

By Dawn Pettinelli - UConn Home & Garden Education Center
Feature Article - posted Wed., Sep. 21, 2011
- Contributed Photo

Although it is hard to think about the bleak days of January amid September’s abundant harvest, those long, cold days are not really that far off. A little bit of thoughtful preparation now can fill wintry days with fragrant and cheerful blooms. While you are purchasing your bulbs for fall planting, be sure to select some for forcing into bloom, as well. Actually, I like to think of it as “gentle persuasion”!

Certain varieties of tulips, hyacinths and daffodils, as well as various smaller species of spring flowering bulbs such as muscari, scilla, crocuses and netted iris, are good for forcing into bloom and are typically marked as such. Their growing conditions are manipulated to fool these bulbs into thinking it is springtime in the middle of winter. As a general rule, the larger the bulb, the longer its required cooling period.

There are three stages involved in forcing bulbs – a period of root growth, time to meet a bulb’s chilling requirement, and bringing into flower. Bulbs are selected and potted up sometime in the next few weeks. Use a light, well-drained potting mix. I generally use the same soilless mix I use for my containers, but if you wish to make your own, I have had good luck with equal parts of peat moss, sand or perlite, and sterilized garden soil.

Bulbs can be planted in a variety of containers, with drainage holes being an essential requirement. I like to use either bulb pans or azalea pots. Both of these pot types are wider and shallower than typical planting pots. The extra width accommodates the hefty root system of many bulbous plants, plus the pots will be more stable and less likely to topple over. A 6-inch pot will easily hold three hyacinths, four or more daffodils, six tulips, and 10 or so crocuses.

After filling the pot about half full with slightly-moistened potting mixture, position the bulbs so that the tips are just below the rim. Tulips should be planted with the flat side of the bulb facing the pot. That way, the first leaf will grow outwards. Cover the bulbs with more potting mix, making sure that the tips are still exposed. Label pots with variety and planting date. Water well and place in a dark, cool place (50-55 degrees F). It usually takes four to six weeks for the roots to become established.

Next comes the chilling part, and this is often a hard location to find. Pots need to be kept at about 35 to 40 degrees F and in the dark. Usually, older homes are more accommodating than newer, well insulated ones. The goal is to keep the bulbs from freezing. Use of a thermometer is advised, and a little experimentation is in order. Some ideas include near doors and windows in unheated basements, in window wells or cold frames covered with a foot or more of hay or leaves, in trenches dug in the garden and covered with hay or other materials, or in a second refrigerator.

Pots need to be checked every couple of weeks. They should not dry out. Smaller bulbs like crocuses and scilla require about eight weeks of 35-degree F temperature, while larger daffodils, tulips and hyacinths need 12 to 14 weeks.

After their chilling requirements are met, bring the pots back into 55- to 60-degree F temperatures and indirect light for about two weeks. A few pots can be brought in each week for a succession of bloom. Bulbs can then be placed in a warmer, well-lighted location. They should bloom in three to four weeks. Keep in mind that too high temperatures or too little light will cause plants to become leggy.

While forcing bulbs may seem like a bit of trouble, it is not really difficult. Just think of how wonderful it will be to have a little bit of spring bursting forth to help banish those winter blahs!

For more information on forcing bulbs or on any other home and garden topic, call the UConn Home & Garden Education Center, toll-free, at 877-486-6271, visit, or get in touch with your local Cooperative Extension Center.


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