How to force bulbs indoors
Ready for a little indoor color this winter? Forcing flower bulbs indoors is a great way to enjoy flowers during the cold months. It all starts with choosing the right type of bulb. Early-flowering spring types are easier to force, or make to bloom indoors sooner than they would outdoors.
Flower bulbs that are easy to force
- Grape hyacinths
Bulb sellers will often note in their catalogs which species and cultivars are best for forcing, along with number of weeks from planting to bloom. Keep reading to see two easy ways to grow them indoors.
Prechilling flower bulbs
Some bulbs require chilling before they can be forced, this mimics the natural process they would experience being in the cold ground throughout winter before blooming in spring. Without this cold period your bulbs may not bloom properly. You can buy prechilled bulbs from mail order nurseries or chill the ones you find at the garden center at home.
How to prechill bulbs
To prechill bulbs, such as hyacinths and daffodils, place them in a paper bag and put it in a refrigerator that's kept at 35 to 48 degrees F for 8-15 weeks. Paperwhites and amaryllis bulbs do not require a chilling period.
Forcing bulbs in water
One of the easiest ways to force bulbs inside is simply in water. You can use a special bulb-forcing jar, a common floral vase or even set a bulb on a grid of wire or clear tape at the water line of any glass or jar.
How to force bulbs in water
- Fill the vase with water to just touching the basal plate of the bulb. That bit of moisture will start roots forming. Once you see them, keep the water line below the bulb to prevent it from rotting or molding.
- Place the vase in a cool, dark spot for a few days until roots are forming and there is an inch or two of leaf growth.
- Move it into a bright spot with temperatures between 60 and 70 degrees F.
- A little sun in the morning or evening is beneficial, but avoid direct sunlight from a south window, or water in the vase will get too hot and your buds may shrivel and dry up before they bloom.
- Rotate the vase a quarter turn every day to keep the plant growing straight.
- You may need to top off the water in the vase if it evaporates over time, still keeping the water level just below the bottom of the bulb.
Forcing bulbs on stones
Don’t have the right size vase to start a single bulb? You can still force spring bulbs in water — you just need a base to hold the bulbs in place above the water level. There are several materials that make good “beds” to anchor your bulbs. Combining layers of different sizes or materials make it look interesting before the plants bloom.
Materials you can use to force bulbs
How to force bulbs on stones
- Set bulbs into the rock with a little push, then add a few stones around each to keep them from tipping. You don’t have to cover them — their roots will work into the base material and hold them steady.
- Bulbs can be close, but not touching to improve air movement and prevent mold from forming.
- Plants may heave out of place a bit if they have vigorous root systems; just tuck a couple stones around the bulb to keep them stable.
- You may need to top off the water if it evaporates over time, still keeping the water level just below the bottom of the bulbs.
Tip for keeping paperwhites from flopping over
Tired of paperwhite daffodils flopping over like those on the left? Try this: When leaves are 1 to 2 in. tall, replace plain water in the vase with a 1:8 alcohol-to-water solution.
The addition of alcohol will stunt the daffodil’s growth just enough to keep the plants compact and sturdy, like those on the right. Use the same solution if you need to add water to the vase until the plant is done flowering.
Types of alcohol you can use to keep paperwhites from flopping over
Don’t overindulge! Too much alcohol in the mixture can kill the plants. Before you add the alcohol mixture, pour out any plain water in the vase so you don’t dilute the alcohol and water mixture.