Hyacinths: Force Bulbs to Bloom Inside
Hyacinths are available in the fall for growing indoors. As hyacinths are a late spring bloomer normally, they do need a period of cooling before they will bloom. There are special pre-cooled bulbs that may be purchased for growing either in pebbles and water, or in containers of soil. Also, pot-size bulbs are sold now for growing over water in special hyacinth glasses. These are fun to grow, and make good Christmas presents if you start early enough — about the middle of October for mid-December bloom. Any way they are grown, they require about eight weeks stored in the dark, between 50° and 60° F. The most likely spots would be in a corner of a cool basement or in the attic. Planted in pots or grown in pebbles, they need only to be checked periodically to make sure they have enough water.
Planting hyacinths in glasses takes a bit more care: first, clean off the base of the bulb, making sure that no remnants of roots remain. A piece of charcoal added to the bottom of the glass is not essential, but does help to keep the water sweet. Add water to the glass until it just touches the base of the bulb . Now put it in the dark, cool spot. Check it in a week or ten days to see if the roots have started to grow. If they have, pour out just enough water so that the water level does not touch the bottom of the bulb.
Hyacinths grown by any of these methods should remain in the dark until there is four or five inches of top growth. It will be a ghastly shade — like the inside of celery – but will become green as soon as the plant is brought into the light. This should be done gradually: first bring the hyacinth into dim light in a cool part of the house, like a north window, for a week or so; gradually move it to a warmer, brighter location. If the hyacinth is grown in soil, make sure the soil stays moist; if in pebbles, the water level should be just under the bulb; and in the hyacinth glass, add water as needed to keep it just under the base of the bulb. To make the hyacinth flower last as long as possible, move it out of direct sunlight once the flower is opened.
Excerpt from “Bulbs That Will Bloom Inside,” Yankee Magazine, October 1980