Here is how to force bulbs indoors: plant spring bulbs in pots or place them in vases in fall, chill them for 12 to 15 weeks at about 35 to 45°F (2 to 7°C), then bring them into a cool, bright room to bloom in winter. A few bulbs, such as paperwhites and amaryllis, skip the chilling.
Forcing tricks bulbs into thinking winter has passed. It is an easy way to get scented flowers in the middle of winter, and it works on a windowsill, in a spare fridge or in an unheated garage. Here are the bulbs to pick, the timeline and how to fix problems.
Quick Answer: Forcing Bulbs at a Glance
- Start: October to November for flowers in January to March.
- Chilling: 12 to 15 weeks at 35 to 45°F (2 to 7°C) for tulips, daffodils, crocus and hyacinths.
- No chilling needed: paperwhites, amaryllis (see below).
- Bring out: when shoots are 2 to 3 inches (5 to 8 cm) tall.
- Bloom: about 2 to 4 weeks after moving into light.
Best Bulbs for Forcing Indoors
| Bulb | Chilling needed | Time to bloom after chilling | Notes |
|---|---|---|---|
| Hyacinth | 10 to 13 weeks | 2 to 3 weeks | Can grow in water vases |
| Tulip | 12 to 16 weeks | 3 to 4 weeks | Choose early, short varieties |
| Daffodil | 12 to 15 weeks | 2 to 3 weeks | Easy and reliable |
| Crocus and muscari | 8 to 15 weeks | 2 to 3 weeks | Small, good for shallow bowls |
| Paperwhite narcissus | None | 3 to 6 weeks from planting | Strong scent, easy in pebbles |
| Amaryllis | None | 6 to 8 weeks from planting | See our amaryllis guide |
How to Force Bulbs Indoors in Soil
- Buy large, firm bulbs in early fall. Ask for pre-chilled bulbs if you want to skip the chilling stage.
- Choose a pot with drainage holes, about 6 inches deep or more, and fill it halfway with potting mix.
- Place bulbs pointed end up, close together but not touching. Tulips can be placed with the flat side toward the rim for tidier leaves.
- Add mix until just the tips show. Water thoroughly.
- Move the pot to a cold, dark place: an unheated garage, basement, cold frame, or a refrigerator with no ripening fruit.
- Keep the soil barely moist. After the chilling period, look for roots at the drain holes and yellow-white shoots 2 to 3 inches tall.
- Move to a cool (60 to 65°F / 15 to 18°C), dim room for a few days, then to bright, indirect light. Turn the pot regularly.
Forcing Bulbs in Water or Pebbles
Hyacinths do well in special forcing glasses. Fill the glass so the water sits just below the base of the bulb, and chill in a cool dark place until roots fill the glass, usually 8 to 10 weeks. Paperwhites can go straight into a bowl of pebbles with water just below the bulbs, and grow in a warm, bright room. Never let the bulb base sit in water, or it will rot. A shot of rubbing alcohol diluted in the water is sometimes used to keep paperwhites shorter, which also helps stop them flopping over.
For more on specific bulbs, see our guides to hyacinths, amaryllis bulbs, daffodil bulbs and how to plant bulbs in pots for outdoor containers.
Common Problems When Forcing Bulbs
- Tall, floppy stems: too warm or too little light. Move somewhere cooler and brighter.
- Bulbs rotting: soil too wet or bulbs sitting in water. Water sparingly and use drainage.
- Short stems, flowers in the foliage: chilling was too short. Allow the full period.
- No flowers: small or old bulbs, or chilling temperature wrong. Use large, healthy bulbs.
- Mice or rodents: chill in a sealed container or cold frame with mesh.
After the Flowers Fade
Forced bulbs use up most of their energy, so they rarely flower well indoors again. Daffodils, crocus and hyacinths can be planted outside after the flowers fade and the foliage has died back; they may recover over a couple of seasons. Check your zone on the USDA Plant Hardiness Zone Map before planting out. Forced tulips and paperwhites are usually composted. Keep pets away from bulbs and flowers; many, including daffodils, tulips and hyacinths, are toxic according to the ASPCA toxic plants list.
Conclusion
Forcing bulbs is mostly a waiting game: start in fall, chill for the full period, then warm them gradually. Choose easy bulbs like hyacinths, daffodils and paperwhites for the best results, and you will have fragrant spring color while the garden is still asleep.
FAQ
How long does it take to force bulbs?
Usually 14 to 20 weeks from potting to bloom: 10 to 15 weeks of chilling plus 2 to 4 weeks in the light.
Can I chill bulbs in the refrigerator?
Yes, in a paper bag in the crisper drawer, away from ripening fruit that gives off ethylene gas, which can damage flower buds.
Which bulbs are easiest to force?
Paperwhites, amaryllis, hyacinths and daffodils are the most reliable for beginners.
Do forced bulbs bloom again?
Sometimes outdoors, after a season or two of recovery. Indoors, they seldom repeat.
Do I need light while bulbs are chilling?
No. Chill them in the dark so roots grow before the shoots, then move to light once shoots are a few inches tall.
