Forcing bulbs is providing bulbs the conditions necessary to bloom at an earlier time than they normally would. Gardeners in warm climates will force bulbs if they don’t have naturally cold enough winter temperatures to produce a bloom outside.
Order your bulbs for pre-order starting in late spring through late summer. Bulbs for forcing begin shipping in late September. Bulbs for forcing can be ordered and delivered as late as early December. Any climate can force fall-planted bulbs for indoor blooms. Fall planted bulbs for forcing need 12-16 weeks of cold temperatures to produce flowers.
Storing Bulbs for Forcing
Determine where you are going to store your bulbs to give the cold period that is required. Bulbs can be stored in a sheltered outdoor location if your winter temperatures are consistently below 50 degrees during the day. If you are in a warmer climate that does not have the cold temperatures outside you will need to refrigerate the bulbs.
Refrigerating Bulbs for Forcing
If your refrigerator also has fruits and vegetables that emit ethylene gases, remove these fruits and vegetables from the refrigerator. Ethylene gases can cause the bulbs to rot.
If you have a refrigerator that does not store fruits and vegetables that is the best place to store your bulbs for forcing. Do not place your bulbs in the freezer. Freezing bulbs will result in mushy bulbs once they thaw.
How to Force Bulbs Indoors
For best results plant your bulbs in pots prior to placing in their cool location. When potting your bulbs use a container that has drain holes. If the container does not have drain holes place pebbles or rocks at the bottom to increase the drainage.
Planting your bulbs in pots before starting the chilling process allows the bulbs to grow roots during the chilling process. Healthy roots on the bulbs results in reliable and sturdy blooms.
Forcing Bulbs How-To
- When potting your bulbs use a lightweight soil mix.
- The tips of the bulbs should be showing above the soil level. The “neck” of the bulb will be at about soil level.
- Plant the bulbs fairly close together as long as they are not touching.
- For a 6” diameter pot plant 4-6 tulips, daffodils or hyacinths depending on the size of the bulbs.
- After the bulbs have been planted add water so it drains through the bottom of the pot
- During the chilling time, regular watering is not necessary. Keep the soil slightly damp. To dampen the soil, spray the soil with a spray bottle.
- Check the bulbs weekly to see if the water is needed, or if any mold is forming. If mold or rot is present hold off on watering until the soil dries out.
- After 12 weeks of chilling the bulbs may be showing green growth sprouting from the tips. Remove the pots from the location they were chilling in.
- It is important that the bulbs are acclimated to warmer temperatures. Moving the bulbs from very cold temperatures to very warm temperatures can shock them into blooming. Sudden temperature changes can cause stunted blooms.
- Store the pots in a location that is between 55 and 65 degrees for about 2-3 weeks. A basement is a great location to store the pots during this transition time. An unheated room in your house would also work.
- After the 2-3-week storage time in the semi-cool location, the bulbs will have some short green growth. The bulbs are now preparing to grow and bloom. Move the pots to a sunny window in your home.
- Now that the bulbs are ready to start growing and blooming provide regular water. When the soil is dry add water until the soil is moist. Only water when the soil feels dry.
- Blooms appear approximately 2-4 weeks after they have been placed in a sunny location.
- After the flowers have finished blooming, they will not have much energy for the next season’s blooms. Therefore, you can discard the bulbs. The bulbs can be planted in the garden; however, it may take 5 years or more until they bloom again.
Chilling Bulbs Before Planting
- If you are unable to plant your bulbs prior to chilling they will still need to be refrigerated. Store bulbs in brown paper bags, they provide good ventilation and darkness.
- After the 12-16-week cold period, it is time to pot up the bulbs. The tips of the bulbs should be visible above the soil.
- Water the potted bulbs after planting.
- Store the potted bulbs in a cool location, like a basement or unheated room. Any location that is between 50 and 65 degrees.
- Keep the pots in this cool area for at least 4 weeks so that they can produce roots prior to sprouting.
- Once you see green sprouts forming move the pots indoors to a sunny location.