Which Bulbs Are Best for Forcing?

Grade Levels: 5 - 7

You've probably seen tulips, daffodils, crocuses, lilies, hyacinths, and other bulbs blooming outside in the spring and summer. The bulbs from which these flowers grow lie dormant all winter, then sprout in the spring or summer when it's time for them to grow.

By altering the biological clocks of such bulbs, however, you can force them to open in the winter, before they normally would. For this project you'll need several different types of flower bulbs, potting soil, trays, and same-size containers.

Plant several of each type of bulb in a pot, being sure to leave uncovered the part of the bulb from which the leaves appear. The broader part of a bulb is generally the bottom, and is the side from which the roots grow. That part should be placed in the dirt so that the roots can grow downward. Once you've planted five or six different types of bulbs, move the pots to a dark, cool place, such as a garage or unheated basement. The temperature should ideally be at about 38 degrees Fahrenheit.

This project requires a good amount of patience and advance planning, for it can take many weeks for bulbs to begin to grow. Once they have, however, and are actively growing, move the pot to an area that receives indirect sunlight and is about 55 degrees Fahrenheit. As the white tips of the plants turn green, increase the amount of sunlight and the temperature. When the buds appear to be ready to open, you can move them to an area that is warmer and sunny.

Rates of growth may vary tremendously between the different types of bulbs, and some may not respond to forcing at all. Just be sure that you use the exact same procedure for each type.

There are thousands of science fair projects that deal with botany, many of which you can probably think of on your own. Just identify a problem relating to plants, and use the scientific method to reach a conclusion.