Fragrant, colourful hyacinth produce beautiful flowers indoors when grown in water, which is especially easy with special vases called "hyacinth jars." Hyacinth bulbs can be tricked into blooming by regulating temperature in a process called forcing. All hyacinths are suited to forcing in water, although the hybrids developed for forcing are easiest to bloom.
Purchase a hyacinth jar, which is shaped like an hourglass, at a florist or garden supply store. Select a firm, heavy hyacinth bulb that fits into the top opening of the hyacinth jar without tipping. Set the bulb, large side down, in the hyacinth jar.
If you cannot find a hyacinth jar, use a small vase or glass bowl that accommodates the bulb without too much excess space around the sides. Fill the bottom of the vase or bowl with 3 inches of glass pebbles, set the bulb, large side down, on the pebbles and add more glass pebbles to weigh down the bulb.
Fill the hyacinth jar with water to just below the bottom of the bulb. If using a regular vase or bowl, add water to the bottom of the bulb. If the water touches the bulb, it can cause rot. Add a tablespoon of aquarium charcoal to the water. This will help keep the water fresh. If the water gets green or cloudy, pour it out gently and add fresh water, with more charcoal and a few drops of household bleach.
Place the "planted" hyacinth bulb in a dark location with a temperature of about 4.44 degrees C. This can be an unheated garage, basement or refrigerator. The roots will start to develop and the bulb will be ready for the next step in three to four weeks. The roots have developed enough to move the bulb into sunlight when they are about 6 inches long and full, filling up a good portion of the bottom of the jar.
Move the hyacinth bulb in the jar to a warm location with indirect sunlight. Green shoots will appear, followed by hyacinth blooms in about 6 weeks. Moving the hyacinth to a cool location at night will maintain the bloom for longer.
If you root the hyacinth in the refrigerator, remove ripening fruit from the fridge as gases from the fruit can harm the developing hyacinth bloom.
Hyacinth bulbs can cause skin irritation; wear gardening gloves when handling.