Manipulating the flowering time of hyacinths is quite easy. Instead of only enjoying hyacinths in spring, you can have them in flower from December to April. If you’re a keen gardener who longs for their plants all winter, you might want to try pre-treated bulbs or else force them on a small scale yourself. Here’s how:
Choose the right cultivars:
Here are a few examples but feel free to ask us about the forcing properties of your favorite varieties.
Blue Jacket: Good for forcing for blooms from February to April: use regular bulbs.
Pink Pearl: Use prepared bulbs for forcing for Dec flowering and regular bulbs for Jan to Apr.
Pink Surprise: February to April, regular bulbs.
Carnegie: Use prepared bulbs for January and February and regular bulbs for March and April.
Yellow queen: Regular bulbs for flowering from February to April.
What you’ll need to do:
Store your bulbs at a temperature of between 45F and 50F during the period prior to planting. This period contributes to the cold-treatment time, so it should be adjusted accordingly. Storage should be well-ventilated. Home gardeners can use open paper bags placed in a well-ventilated spot. Open containers such as crates or trays make the best storage containers.
You will plant your December flowering hyacinth bulbs in mid-September and bulbs for later flowering will be planted proportionately later.
Use a good potting mixture that has not been pre-enriched with fertilizer. Pots should be clean and have adequate drainage. One bulb is sufficient for a 4” (10cm) pot and three bulbs are needed for a 6” (15cm) pot. If you’re using a larger container, plant the bulbs as closely as possible together. When planting it is advisable to use gloves, since the bulbs contain organic compounds that can cause a skin rash.
Water the pots well so that the medium is thoroughly dampened and label the pots clearly with their planting dates. The bulbs now need to be kept at 35F – 45F for ten to thirteen weeks before being introduced to room temperatures. Less time may result in malformed blooms and leaving them out in the cold too long, means that the flower stems will ‘stretch’ and may become floppy. If you bought prepared bulbs, your treatment time will be shorter.
Once your hyacinths are growing indoors, they will flower in two to three weeks. If desired you can also lift the bulbs out of their potting material, wash off any dirt around the roots (just hold the end of the bulb under running water) and place carefully into a decorative glass container with some stones or hydro beads and a little water. Prolong the blooms by avoiding direct sunlight, but ensure that the plants get strong, indirect light. When the spring comes, plant them in the garden. Hyacinths can last for a number of years in garden conditions.