BULBS FOR INDOOR BEAUTY

The arrival of fall means it’s time to buy and plant spring-flowering bulbs. This year, why not purchase a few extras to force into bloom this winter? It’s an enjoyable project, and the rewards are great—a house filled with the glorious scents and colors of spring during the coldest months of the year.

The principle behind forcing is simple: Provide the bulbs with cool, autumn-like temperatures for rooting, give them a chilly period to mimic winter, then bring them into warmer temperatures to simulate spring. Just about any bulb can be forced. The time this takes varies with the bulb, but it is usually between twelve and sixteen weeks. Varieties that naturally flower early require less time than later-blooming varieties. Daffodils and crocus force well and are particularly good choices for beginners. Prepared hyacinth bulbs have already had some preconditioning and require a chilling time of only ten to twelve weeks, and paper-white narcissus will flower without any chilling at all.

Any container with good drainage will work for bulbs, though typically shallow containers are used because they are proportionate to the final height of the plants. Choose a container that is large enough to accommodate a mass of bulbs, planted so that they are close together, but not touching. It is best to plant only one variety per pot to be assured that all the bulbs will come into bloom at the same time. If the containers have been used before, clean them with a bleach solution or run them through the dishwasher to sterilize them.

Place gravel or pot shards in the bottom of the pots, then partially fill them with sterile potting soil. Place the bulbs so that their tips are near the rim of the pot, fill in with the remainder of the soil, and tamp down lightly. The pointed end of the bulbs should be almost even with the soil surface. For the best results, always plant tulip bulbs with their flat sides facing the outside of the pot.

Label containers with the variety and the date the bulbs were planted, then water them gently from above or place the pots in a tray of water to absorb moisture from the bottom. After watering, allow the pots to drain for at least one day.

Bulbs must then be chilled for twelve to sixteen weeks in a dark spot. Ideally, they should be chilled at 45 degrees for about five weeks, then at 35 degrees for the remaining six to eight weeks of cold treatment. A refrigerator works well for this treatment. Do not store the bulbs near fruit, though, as some fruits release a gas that causes the flower buds to die. An unheated garage, porch or window well can also function as a chilling space. Be sure to place the bulbs in boxes or cover them with burlap to keep out the light. Check the pots every couple of weeks for water, but they are not likely to need much—the soil needs only to be slightly damp.

A coldframe is an ideal place to chill the bulbs. Leave the bulbs uncovered until the ground has begun to freeze, then mulch them with a layer of leaves, straw or bark.

Another alternative is to heel the pots into a trench or raised bed in a protected area of the garden. Fill the trench with sand, gravel or peat moss mixed with perlite or polystyrene. This provides drainage underneath the bulbs and makes the pots easier to dig out. Protect the bulbs from rodents by laying chicken wire on top of them. Cover the pots with mulch when the ground begins to freeze.

After about ten to twelve weeks, check to see if the bulbs have developed good roots and visible shoots. Once these have formed, move the pots to a cool area out of direct sun, perhaps a basement or unused room. Keep them in these conditions for several days, and then move them to a spot where they will get direct light. Begin to water in the same manner as for a houseplant, and turn the pots frequently to assure the stems grow straight. Plants should flower within about two to three weeks. The time required for blooming decreases as spring approaches and the days grow longer. Flowers will last longer if the plants are moved to a bright spot out of direct sunlight as they begin to bloom.

If the bulbs are to be planted outside, fertilize them with a liquid fertilizer as they start to flower, and continue to do this until the tips ofthe foliage turn yellow. After the last frost, plant the bulbs outside in the garden, or allow them to go dormant in the pots, store them for the summer, and plant them in the fall.

Selected Bulbs and Estimated Forcing Times

• Crocus 14-15 weeks
• Hyacinths (not prepared) 11-13 weeks
• Hyacinths (prepared) 10-12 weeks
• Iris reticulata 13-15 weeks
• Muscari (Grape Hyacinth) 14-15 weeks
• Narcissus ‘Dutch Master’ 13-16 weeks
• Narcissus ‘Ice Follies’ 14-16 weeks

Date: September 30. 1999
Author: Maureen Safarik
Maureen Safarik is a Horticulturist at The Planter’s Palette