GARDENING: Planting and forcing flowering bulbs for early blooms in spring

GARDENING: Planting and forcing flowering bulbs for early blooms in spring

Fall is the time for finishing up in the garden after a season of growing and harvesting. But the next spring can seem just around the corner with the planting of bulbs. Bulbs can be planted both in the ground and in pots for forcing inside during the late winter and early spring when colorful flowers are needed most.

In the Northeast, tulips, daffodils, crocus, scilla, snowdrops, grape hyacinths and hyacinths do well when planted outside in the fall. Buy from a reputable plant seller as they know how to transport and handle the bulbs to keep them healthy. A few days in a hot tractor trailer at temperatures over 100 degrees can kill or distort the flower inside each bulb, and in that case, “You get what you pay fo.”

True bulbs have a basal plate at the bottom where the roots originate. Above the basal plate are concentrically arranged leaf scales, wider at the bottom, that come to a point, creating a tear-drop shape. Always plant bulbs with the pointed end up.

Inside those leafy scales is stem tissue that protects the developed flower bud in the center. Tulip, daffodil, hyacinth, scilla, oriental lilies, netted iris and snowdrops belong to the true bulb group. All of these bulbs are hardy in Connecticut and should be planted early to mid-fall to allow the roots to establish before the ground freezes.

Locate bulb beds in well-drained soil in a place with part to full sun. Have a test done to determine soil pH and nutrient levels. Bulbs need phosphorous for good root development. If phosphorus is needed, work bone meal or superphosphate it into the top 6 to 8 inches of soil.

Without a soil test, four cups of 10-10-10 or a similar fertilizer per 100 square feet can be worked into bulb beds before planting. Place the bottom of the bulb two to three times the height of the bulb. Larger bulbs of daffodils, hyacinths and tulips should be put in a hole 8 inches deep, smaller bulbs 3 to 4 inches deep. The pointed end of some bulbs is not obvious; these can be planted sideways. Water the bulb bed after planting to settle the soil and encourage root growth. The bed should receive an inch of water per week via rain or watering. Lightly mulching the bed will help to protect the plantings.

After bulbs bloom next spring, cut back the flower stalk, leave only the green foliage. The leaves are the food factory making carbohydrates to store in the bulb for the following year’s flowers. If you cut them back too early, the plant will not bloom the next year.

If you have animal pests, take some precautions. Hot pepper flakes sprinkled over the bed might deter squirrels from digging up the bulbs. So will commercial animal repellents sprayed on the soil. Soak bulbs in a commercial liquid animal repellent that adds a layer of bitter-tasting chemical to the bulb. One bite and that little rodent learns to stay away. Treat tulips and crocus with these repellents. Daffodils, scilla, snowdrops, grape hyacinth, hyacinth and alliums are naturally deer-resistant.

Forcing bulbs

Forcing potted bulbs to flower is done by mimicking nature to provide the required amount of time the bulbs will need to be exposed to cold temperatures. Giving them some warmth from our homes or a greenhouse will then trigger their internal clock to come out of dormancy. Tulips, daffodils, hyacinths and grape hyacinths, and scilla and crocus all respond well to forcing.

For forcing, you will need top-quality bulbs, containers, planting medium and a calendar. Timing is important, because forgotten pots will not produce well. Use heavy containers so top-heavy plants will not topple over, and be sure there are drainage holes in the bottom. Place at least 2 inches of moistened container mix in the pot before positioning your bulbs. Fill the container to within a half inch of the top of the pot. Larger bulbs can poke out of the soil a bit. Smaller varieties should be completely covered. Water thoroughly, letting excess water drain out. Do not let pots sit in water.

The bulbs need to chill for 12 to 16 weeks. Keep the potted bulbs at 35 to 50 degrees. You can put them in a refrigerator as long as it contains no fruit — ethylene gas given off by fruit can retard bulb growth. Pots can also be placed outside in a spot where they are accessible, such as a cold frame or in a rodentproof container in a shed. Cover the pots with leaves or straw for extra protection.

The goal is to give the bulbs the required cold period, and to retrieve the pots when the ground is frozen. Mark your calendar to bring the pots inside after 12 to 16 weeks. For the first week indoors, set the pots in a cool spot of 50 to 60 degrees. Begin watering when you see the start of growth. After one week, move the pot to a warmer room and place it in a bright spot near a window, rotating the pot to keep the stems straight. Provide sticks and twine for support if needed. In about four weeks, the blossoms should open.

Carol Quish is a horticulturist. For more information on planting bulbs, or other horticultural topics, contact the  UConn Home & Garden Education Center, 877-486-6271;, or contact your local Cooperative Extension center.      




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