Hyacinths are extremely fragrant spring flowers and one of the easiest to grow indoors. They can be forced to bloom out of their season in either regular potting soil or in plain water in a specially shaped hyacinth glass. Because they’re so fragrant, don’t put them on the dinner table; you and your guests will smell and taste them instead of your food.
Decide which container to use. You can use a bulb pot, a clay pot or a hyacinth glass, which is a vase-shaped glass with a narrow neck and a wide base. The narrow neck holds the bulb above the water. The roots grow out of the bulb and into the water in the wide base.
Prepare the container. If you are using a hyacinth glass, wash it thoroughly. Add enough water so it comes about halfway up the narrow neck. For hyacinths that will be forced in soil, place a rock or pot shard over the drainage hole. Fill the pot up about halfway with potting soil.
Plant the hyacinth bulbs. To grow them in a special hyacinth glass, simply place the bulb into the top of the glass with the pointed end up. Check the level of water; it should come up just to the base of the bulb. Add or remove water as needed.
For forcing hyacinths in potting soil, set the bulbs on top of the half-filled pot with their pointed ends up. Depending on the size of your pot, plant three, five or seven bulbs. They should be fairly close together, but not touching. Add enough soil to cover the bottom 2/3 of the bulbs, leaving the top 1/3 exposed. Water thoroughly until it drains out of the bottom of the pot.
Put the hyacinth glass or pot into a cool, dark place for about 12 to 14 weeks. The temperature should be between 33 and 48 degrees Fahrenheit. Check the bulbs about every seven days. Add water as needed to the hyacinth glass to maintain the level of water at the bottom of the bulb. Water hyacinths in potting soil so the soil stays moist but not wet.
Bring into temperatures of 55 to 60 degrees Fahrenheit and place in a bright, north-facing window when the shoots are about 1 to 1 1/2 inches tall. Maintain the same watering criteria as in Step 5, and keep the bulbs out of direct sunlight. They should bloom in two to three weeks.