Question: I enjoyed your column on bulbs. I would love to plant bulbs in containers, both for indoor and outdoor flowering. Could you explain how to successfully grow bulbs in containers?
Answer: Fall bulbs like tulips, daffodils hyacinths and crocus as well as other minor bulbs can be grown in various size containers.
Large patio tubs or planter boxes are best for outdoor bloom although ordinary pots can also be used. All containers should have holes or seams for drainage. Containers should be filled with potting soil or an artificial soil mix with good drainage. Add some long lasting fertilizer such as osmocote or granular organic.
Cover bulbs with soil equal to the bulb diameter. If soil is soft, bulbs can be pushed into the soil without digging holes. Place bulbs close together in containers. They should be almost touching.
One or several different types of bulbs can be planted in one container. For large containers place the tallest growing bulbs in the back or center of the container with shorter ones toward the front or outside. Shorter tulip and daffodil varieties will stand up much better. Miniature daffodils and other small bulbs are best for smaller containers.
Containers can be placed outdoors wherever you want during the growing process. Bulbs will not freeze if they are kept moist. They should be placed where they receive at least a half day of sun when they start to emerge. Bulbs will bloom at about the same time as they would if planted in the ground.
Bulbs in containers for inside bloom should be planted so they are just barely covered. This will give them more room for roots to develop. Special glass containers are available for individual hyacinth bulbs.
After planting and watering, containers should be placed in the dark for approximately 12 weeks at a temperature of 40 to 45 degrees, At this temperature they develop a good root system. This is the temperature at which refrigerators are operated. Soil should be kept moist during this period. After 12 weeks roots will begin to show at bottom drain holes and tops will begin to sprout.
Containers should be placed where they can get direct sunlight or high intensity lighting. They will begin blooming a week or two after bringing inside.
Repeat planting will allow repeat blooming over a long period. Simply count backwards 14 weeks from the time you would like to have them in bloom.
Paperwhite Narcissus will bloom without cooling pre-treatment.