Art in the garden: The secret of forcing bulbs to bloom indoors
Yes it’s time to plant spring flowering bulbs, but this year, why not purchase a few extra of your favorites to force into bloom indoors this winter? The rewards are great — a home filled with the sweet fragrances and brilliant colors of spring during the coldest, dreariest months of the year.
The principle behind forcing is simple. Give bulbs cool, fall-like temperatures for rooting; replicate a colder period to mimic winter; and then warm them to simulate the onset of spring.
Just about any bulb can be forced. The time it takes varies depending on the bulb, but forcing typically takes somewhere between 12 and 16 weeks.
Varieties that naturally flower early require less time than late-blooming types. Daffodils and crocus are easy to force and good choices for beginners. Paperwhite narcissus will bloom without any chilling.
Choose any containers with good drainage. Make sure they are wide enough to accommodate the desired number of bulbs so they are close together but not touching. Place gravel in the bottom of pots and partially fill with potting soil. Nestle the bulbs into the soil and cover them with more soil so that their tips are just above the soil surface. When planting tulips, position bulbs with their flat sides toward the outside of the pot.
Label the container with the variety and the date the bulbs were planted. After watering, give the pots plenty of time to drain before chilling.
Bulbs must be chilled in a dark spot. Ideally, they should be chilled at 45 degrees for about 5 weeks, then at 35 degrees the remainder of their cold treatment. A refrigerator works well, but don’t store bulbs near fruit. Some fruits release a gas that causes flower buds to die. An unheated garage can also serve as a chilling space.
Wherever bulbs are chilled, they must be covered with burlap or placed in boxes to keep out light. Check the pots every couple of weeks and water if necessary. Be careful not to overwater — the soil needs only to be slightly moist.
Another option is to put your bulb-filled pots in a trench in a protected area in the garden. Fill the bottom of the trench with coarse sand, gravel or peat moss for drainage underneath the bulbs. Set the pots in the trench and cover them with chicken wire to protect bulbs from rodents. Cover the pots with mulch when the ground begins to freeze.
After 10 to 12 weeks, if bulbs have developed roots and visible shoots, move pots to a cool area out of direct sun. Leave them there for several days before moving them to a spot in direct light. Begin to water them as you would most houseplants and turn pots often to assure straight stems.
Bulbs should send up flowers within two or three weeks. Flowers will last longer if you move them out of direct sun to a space in bright, indirect light.
Estimated forcing timeŸCrocus: 14 to 15 weeksŸHyacinths, not cold-prepared: 11 to 13 weeksŸ Hyacinths, cold-prepared: 10 to 12 weeksŸ Muscari (grape hyacinths): 14 to 15 weeksŸ Daffodils: 13 to 16 weeksŸ Tulips: 12 to 16 weeksŸ Diana Stoll is a horticulturist and the garden center manager at The Planter#146;s Palette, 28W571 Roosevelt Road, Winfield. Call (630) 293-1040, ext. 2, or visit planterspalette.com. 18372130Botanical tulips are the perfect size for small containers.