Forcing Bulbs for Indoor Beauty This Winter

By Jan Cashman • Posted on November, 25th 2009

by Jan Cashman

By now, if you were going to plant spring-flowering bulbs in your garden, hopefully, you have completed that task.  But, many of us like to plant bulbs in pots and “force” them to bloom early for flowers and color indoors during the winter.    It is not hard to force bulbs, but a few steps must be followed for success.

What Bulbs to Force

Hardy tulips, narcissus, hyacinths, and crocus all force well.  Flowers with shorter stems work better; they won’t tip over as easily.  When you purchase them, look on the label to see if they are “good for forcing.”  Plant only one variety per container.  Tender paperwhites narcissus and amaryllis are for forcing indoors only, since they will not survive our winters in the ground outside.

Planting

Any pot can be used for forcing bulbs.  If your pot doesn’t have drainage holes, put gravel in the bottom to help with drainage.  Use any bagged potting soil.   The noses of the bulbs should be exposed; do not bury the bulbs.  You can plant bulbs closer together in a pot than you would in your garden.  A six inch pot can hold up to 6 tulip or daffodil bulbs or 15 crocuses.

Watering

Water your pots immediately after planting; then keep the soil uniformly moist during the cold treatment period and after, when they are brought in the house.

Cold Treatment

Bulbs need a cold temperature treatment of 35 to 48 degrees for 10 to 12 weeks or more.  A dark crawl space or garage that stays cool but doesn’t freeze works well for this.  During this time the bulbs grow roots.  After their roots are well formed and the shoot has started to emerge, bring them into a slightly warmer location for a couple of days, then into the house.  The bulbs will flower in 3 to 4 weeks.

Forcing in Water

Crocus, narcissus, and fragrant hyacinth can be forced in water in clear, glass vases made for this.   Place water in the bottom of the vase and the bulb in the top.  Water should come just to the base of the bulb; the roots will reach down into it.  Never submerge bulbs!  Hardy bulbs like hyacinths will still need a chilling period in a cool, dark room, for 8 to 12 weeks for the root system to develop. You will know it is OK to bring the bulb into the warmth of your home when the shoot is 2-3 inches high.   You can also use pebbles, gravel, or marbles in a decorative container; the pebbles will support the bulbs.

Paperwhites

The ‘force in water’ method also works well for non-hardy, wonderfully fragrant paperwhites.   A short, 2 to 3 week, chilling period is recommended for paperwhites, but they will do fine with no chilling.  You can also grow paperwhites in a flower pot with soil.

Amaryllis

The huge flowers of amaryllis are striking in any home.   Amaryllis need no chilling time.  Plant them in a pot in sterile soil so 1/3 to ½ of the bulb is exposed.  Keep in a warm spot in your house, water, and in 6 to 8 weeks, you will have flowers.  Once the flowers have developed, a cooler location will prolong flowering time.  Amaryllis can also be forced in just water.

For Christmas, force bright red amaryllis or clear white paperwhites;  pink amaryllis are pretty for Valentine’s Day;  yellow narcissus for Easter.  Whatever bulbs you force now will turn the inside of your home into a flower garden for the long winter months.