A bulb vase can help you force a bulb to grow indoors. Also called forcing vases or forcing glasses, bulb vases suspend bulbs above water to stimulate root growth. This starts the growing process and eventually should lead to the bulb sprouting into a plant and blooming. A well-designed bulb vase has a narrow space that the bulb cannot fall through, which keeps it out of the water, and the vases can made from a variety of materials, such as glass or plastic, and should be watertight.
A specially designed bulb vase often is not necessary to force a bulb to grow. Any functional vase that allows the bulb to remain suspended above the level of water should work. Some people get good results growing spring bulbs such as paperwhites in large pots or flat centerpiece-style vases by placing several bulbs in one container. This may require more work and materials than using a bulb vase, however.
To force bulbs in larger containers or any vases in which the bulb could reach the bottom, pebbles or other materials will probably be necessary. About half the container should be filled with pebbles. Water should be poured into the container to a level below the top of the pebbles. The bulb is then placed on top, out of the water. A vase or container with any type of drain holes is not suitable for forcing bulbs.
Many types of bulbs can respond well to bulb forcing, such as hyacinth, crocus, or narcissus bulbs. For those that do well indoors, the best vase will be the right size to keep the bulb easily out of the water. Forcing vases usually have an hourglass shape or narrow section to prevent the bulb from falling, though some types of bulbs might be small enough to fit through the narrowest opening on some larger vases. The opposite problem, a bulb that is too large for the upper part of a small vase, could also keep the bulb from flourishing.
The right bulb vase can make growing bulbs a fun and educational experience, especially for kids. Clear forcing vases allow you to see the roots grow to fill the bottom of the container. Keep in mind that some bulbs must be kept in a very cool place for several weeks, so it is not necessary to keep the vase on display. You can also opt for colored and tinted designs so they will match your decor when you are ready to put them in a visible location.