Forcing hyacinth bulbs is the practice of providing a suitable environmental setting so that the plant will bloom earlier than it would under natural conditions. By forcing hyacinth bulbs, you can enjoy their heady fragrance and lush blooms indoors in late winter, or early spring.
Step 1 – Buy Hyacinth Bulbs
The forcing process for hyacinth bulbs takes around 13 weeks. You can buy ‘prepared’ or pre-chilled bulbs for early flowering, because these bulbs need a shorter chilling time of 10 weeks. If you buy regular bulbs, they will need a chilling period of at least 13 weeks. Choose a hyacinth that is amenable to forcing. Some of the suitable varieties are Delft Blue, Lady Derby, Jan Bos, Carnegie, and Anna Liza. Place orders for the bulbs well in advance, preferably in spring, because bulbs are generally in short supply in most garden centers. Forcing can be done anytime from September to November, depending on when you want the plant to bloom.
Step 2 – Prepare the Planting Medium
You can use clean clay or plastic pots or containers to place the bulbs. The pots must have proper holes for drainage. Soak clay pots in water for about a day before use. The planting medium must be capable of good moisture retention, and also good drainage. Use a well-drained potting mix for this purpose. Once the bulbs arrive, store them at cool temperatures, between 7ºC and 10ºC. Ensure good air supply. Be careful about keeping fruits such as apple and pineapple away, because they produce ethylene, which can damage the flower producing capability of the bulb.
Step 3 – Plant the Bulbs
Put on your gardening gloves, as handling hyacinth bulbs can cause skin irritation. Fill the container loosely with the potting mix. Soaking bulbs briefly before planting is also a good idea. Place the hyacinth bulbs in the container, with the pointed top of the bulb slightly above soil level. You can place bulbs close together, but avoid touching. Water thoroughly. Next, the pots need to be stored in a cold, dark place, at a temperature between 2ºC and 7ºC, preferably in a cold garage. Water the pot regularly.
Step 4 – Move the Pot Indoors
Depending on the previous cold treatment before planting, the bulbs will grow shoots after about 10 or 13 weeks. When the shoots are about 1 or 2 inches in height, you can move the pot to a cool spot with direct sunlight, preferably a north-facing window, at around 13ºC. You will see the bulb flowering after a couple of weeks. After flowering, you can move the plant to a warmer location in the house. You can transplant the hyacinth plant in spring after it have finished flowering for the season. Most probably, it will bloom again after a year or two outdoors. However, the same bulbs cannot be used for forcing again, because they will have used up a lot of energy already.