I overestimated the number of spring-blooming bulbs I could plant this year. (Well, to be totally honest how many bulbs my husband could plant for me.) We planted what we could, gave away some and put the rest in a box to “deal with later.” Stumbling across them yesterday, I decided that this was the perfect opportunity to learn how to successfully force bulbs into bloom so that I can enjoy bursts of color and fragrance in the dead of winter.
The last time I tried forcing bulbs indoors it did not end well. I naively thought I could simply put some bulbs in a paper bag, shove them to the back of the refrigerator and then pull them out and plant them shortly before I 
wanted flowers. After about six weeks in the back of the fridge I started smelling something off, but couldn’t for the life of me figure out what it was. Then I saw a leaking paper bag and knew exactly what the awful smell was – rotting daffodil bulbs.
After consulting several reliable sources, I have learned that even though there is a bit more to forcing bulbs indoors than I realized, it isn’t a terribly difficult task. With proper planning and preparation, you can have beautiful blooms throughout the winter months.
For the novice, choosing the right bulbs is the key to success. Look for high quality bulbs; those that are large, firm and unblemished are good choices. Daffodils, hyacinths, crocus, grape hyacinths and tulips are typically the easiest bulbs to force for indoor blooming.
Regardless of the type of bulb you choose, a 12 to 16 week chilling period and a 2 to 4 week growing period will be required for the plant to produce flowers. Bulbs planted this week, for example, could be ready to bloom as early as mid-February or as late as mid-March.
The preferred method for forcing bulbs is to pot them first and then place them in a dark, protected location where temperatures consistently hover between 35 and 48 degrees F. An unheated basement or garage, a cold frame, a trench or a refrigerator are some of the best places to store bulbs during the cooling period. Bulbs in pots should not freeze. Under ideal conditions, the pots of bulbs should only need occasional moisture.
Although a refrigerator can be an excellent choice for a chilling location. It can also be a death trap for your bulbs. If you are also storing ethylene gas producing fruits and vegetables in it. Ethylene gas is a natural, clear, odorless, tasteless hydrocarbon gas produced and emitted by a variety of fruits and vegetables. Over time, the gas makes the texture of produce softer, the taste sweeter and the color deeper. Over too much time, or for any sensitive fruit or vegetable, the gas hastens rot. Unfortunately bulbs are extremely sensitive to the gas. (I can certainly attest to that!) One source suggested removing your ethylene producing fruits and vegetables while the bulbs are chilling, but that seems an unreasonable suggestion for most households. Another advised keeping bulbs in a sealed plastic bag, but opening the bag once a month for 2 hours to allow fresh air to circulate in the bag, then resealing it again.
After 12 weeks have passed, begin checking pots for signs of root growth and emerging yellow shoots. When you see evidence of growth, move the pots to a somewhat warmer location that receives medium to low light. Placing them in a warm, sunny room can force rapid growth that will produce only short-lived, weak blooms. After an adjustment period of 4 or 5 days, move the pots to a brightly lit, warmer location. Keeping them away from full sun and warm drafts will help the plants stay in flower longer. Once a forced bulb finishes blooming, it is usually best to just throw it away. It can be planted in the ground, but if it survives it usually takes at least six years to rebuild enough energy to bloom again.
The actual potting process is relatively easy. Choose pots that are 4 to 8 or 10 inches in diameter. Azalea pots work well. Use a light-weight potting medium that has excellent drainage ability. Surprisingly, high fertility is not particularly important because the bulb supplies its own energy. Don’t fertilize at planting.
Fill the pot with an initial layer of soil, using enough so that when placed, the neck of the bulb will be above the soil line. Fill in the potting medium around the bulbs, being careful not to pack the soil too tightly. For a striking
display, fill the pot with as many bulbs as possible, without having the bulbs touching each other. For flat sided bulbs like tulips, place the bulbs so that the flat side is towards the outside of the pot. This encourages the leaves to form around the rim of the pot, creating a natural vase for the blooms.
You can plant pots with single varieties or you can mix in smaller bulbs like grape hyacinth or crocus. Plant the smaller bulbs lasagna style (in layers) so that the smaller bulbs sit an inch below the surface, but not physically resting on top of the bottom layer. While the bulbs may not all bloom at the same time, using a mixture of bulbs can bring the sense of a flower garden inside.
Once the pots are planted, water them thoroughly, making sure that water drips out the drain hole. If the pot has a sauce, make sure that any remaining water is dumped out before the pot goes to the chilling location.
Some bulbs, especially hyacinths and paperwhites can be forced in a vase of water. A hyacinth vase is an hourglass shaped vase that is used to force a single bloom. The bottom portion of the vase is filled with water and a pre-chilled bulb sits in the upper half. The bottom of the bulb needs to be directly above the water, but must not touch the water. If the bulb sits in the water, it will rot. Check the water level frequently and change it when it becomes cloudy. Pre-chilled bulbs can be ordered online or purchased from some garden centers, or you can chill hyacinths yourself using the same locations as described above.
Having done my research, I’m ready to try again. Maybe this time I’ll be able to sit back and enjoy some flowers instead of spending an afternoon cleaning out a smelly refrigerator.
