Forcing Hardy Bulbs
Martha Maletta, Horticulturist, RCE of Hunterdon County
Article Dated October, 2001

If spring flowers in January sound appealing, pot hardy bulbs now for indoor forcing. Varieties of crocus, hyacinths, daffodils, tulips, squill, glory-of-the snow and iris reticulata are reliable. Beginners should probably stay with crocus and hyacinth; intermediates may try small cup and medium size daffodils; leave early single and double tulips for the experts.

In forcing hardy bulbs to bloom out of season you will have to provide them with a "fall and winter" during which roots develop and dormancy is broken and "spring" when leaves and flowers grow. So, potted bulbs will need 10 to 15 weeks in the dark at 40-50° and then 4 to 6 weeks in a very bright, even sunny, but cool (60-65°F) spot.

Buy medium (rather than "jumbo" sized, undamaged bulbs, planning for at least 3 bulbs of the same type per container. Special bulb pans are available but any container will do as long as it has good drain holes - bulbs sitting in soggy soil are doomed. Use commercial potting soil or your own mix of equal parts loam, peat moss and sand. Plan the potting so that all the tips of the bulbs will just show at the soil sulfate about one inch below the container rim. The bulbs should just fit into the pot with a little space around each one.(Place tulips with flat side of bulb against the side of the pot) Soil should be settled into the container by rapping the pot and by gentle pushing; don't compact the soil or press the bulbs down into it. Water the planted pots thoroughly (from the bottom) and drain well! They will be watered again only if they begin to dry out during the "winter" phases of forcing.

Move the pots to their cool, dark storage place. This may be any unheated area of your house or even the refrigerator, if you can spare the space. Outdoors, any location where you can protect the pots from below freezing temperatures and where they won't be frozen into the soil, will do. They could be packed in a box, with insulating material, and stored in the garage, or on the north side of the house. Keep an eye on things. Water if necessary and watch out for evidence of mice; screen will keep the bulbs safe. As temperatures drop, provide more insulation to prevent freezing.

When roots are poking through the drainage holes and shoots peeking from the bulbs and 10 to 15 weeks of 40-50° temps have passed, the next phase of forcing can begin. Move the pots to their bright, cool spot after about a week of gradual transition from "winter to spring". Turn them frequently, water when needed, and stake tall plants as they grow. Once the blooms appear, they will last longer if the plants are moved to a less bright location.

Forced bulb can go ito the garden. Keep the leave growing until outdoor work is possible. Then plant the clamp, as it comes from the pot, with the base of leaves an inch or more below ground level, disturbing the plant as little as possible. Don't save forced bulbs for forcing again -- it just won't work.

For some more detailed information on this topic, please send a self addressed stamped envelope to:
Rutgers Cooperative Extension of Hunterdon County
4 Gauntt Place
PO Box 2900
Flemington, NJ 08822-2900
and ask for a copy of
"Forcing Hardy Bulbs Indoors"

The tender bulbs of paperwhite narcissus (Narcissus tazetta varieties) potted now, can provide spring blooms for Thanksgiving. Later plantings will bring spring to the December holidays and beyond. Paperwhite narcissus are easy but need cool (60°) growing temperatures to really succeed. They can be planted in pots of soil but are usually grown in decorative bowls with stones and water. "Plant" the bulbs so 1/3 to 1/2 shows and maintain water just to the base of the bulbs. Whether they are stared in the dark or placed immediately in the bright location where they will grow, keep them cool. A good technique for providing attractive support for leaves and flowers - plant the bulbs in a clear fish bowl.