General

Hyacinths are generally used for container forcing, but make good cut flowers as well.

All varieties are suitable for spring production outside and greenhouse forcing during winter and spring. Please indicate to your supplier for which purpose you will be using your bulbs. This way they can give the appropriate pre-cooling when necessary.

Growing Area and Planting

For field production, Hyacinths need to be planted in the fall when the soil temperature has dropped below 55 Fahrenheit. For southern states (zones 8-9) hyacinths need to receive at least 6 weeks of pre-cooling prior to planting. Hyacinths should be planted on 4" centers for outside as well as greenhouse production. When Hyacinths are forced in containers, plant one bulb in a 4" pot, three in a 6" pot and 5 to an 8" bulb pan.

For greenhouse production Hyacinths should be forced as follows:

Plant Hyacinths in the fall in containers and move containers into a rooting room at 48 Fahrenheit (cooler). Keep the containers at this temperature until roots start growing out of the bottom of the container and the shoot reaches a length of 1" tall. If the roots are visible and the shoot has not developed yet, the temperature in the cooler should be lowered to 41 F until the shoots are 1" tall. This process, from planting the bulbs to moving them into the greenhouse, takes approximately 10 weeks.

If no cooler facility is available, the bulbs can be planted outside under a 6" sand or straw cover. This method is only recommended in the northern states where outside soil temperatures make it possible to do this. Once plants are moved to a low light level greenhouse, the plants can be finished. For cut flower production cover the plants the first 3 to 4 days with newspaper to increase the height of the stalk.

Timing

Hyacinths that have been planted in containers and are started in the rooting room will only take 3 to 4 weeks to finish once they are moved into the greenhouse. The containers have reached their pre-finished stage. Mid season (October) plantings take only 2-3 weeks to finished stage. Late season (November) plantings take as little as 1-2 weeks to finished stage. Containers that have reached their pre-finished stage can be held back for at least 3-4 weeks if held in a cooler at 33-34F.

Soil Requirements and Watering

Plant bulbs in a sterilized, well draining planting medium, with a pH of 6-7, approximately 3 inches deep. Dip the bulbs prior to planting in a fungicidal solution to prevent disease problems. You can use Captan, Cleary's, Domain or a combination of these fungicides. After Hyacinths are planted, it is recommended to top dress the growing medium with a layer of half an inch of heavy sand, especially when a light weight type of potting soil is used. After planting, water the containers or beds really well. Once growth appears, the soil needs to be kept slightly moist. Irrigate plants in the morning, so the crop can dry during the day.

Fertilizing

Fertilizing should start as soon as the plant is 2" tall. An application of Calcium Nitrate at a rate of 2 lbs. per 100 gallons on a weekly basis is recommended. Calcium Nitrate will help to prevent stem topple, which is a physiological disorder associated with greenhouse forced Hyacinths.

Greenhouse

Use a medium light greenhouse with proper ventilation. Keep night temperatures at 55 F and day temperatures of 65 F. You can use drip or overhead irrigation. Drip is preferred when bulbs are planted close together or grown in pots.