Forcing Spring Bulbs Indoors: A Step-by-Step Guide to Early Blooms

Tulips, hyacinths, grape hyacinths, and Iris reticulata can bring spring indoors weeks ahead of schedule. During the dreary winter months, you’ll enjoy the powerful fragrance of hyacinths, the sweet scent of paperwhite narcissus, and the cheerful colors of tulips and other spring bulbs—if you plan ahead.

While fooling Mother Nature isn’t difficult, you can’t rush the process. Most spring bulbs require 8–15 weeks of chilling, though a few varieties are ready in just 2–3 weeks.

Learn more about gardening with beautiful bulbs such as fritillaria.

Chill Out!

When chilling bulbs in the refrigerator, store them away from fresh fruits and vegetables that emit ethylene gas, which can damage developing flowers. Keep potted and loose bulbs in closed paper bags.

Unless labeled “prechilled,” most flowering bulbs need a period at 35–45°F to root and flower. (Amaryllis and paperwhites are exceptions—they can be potted, watered, and placed in a bright spot.) Chilling duration varies by type; see the chart at the end of this article.

In general, smaller bulbs—crocus, grape hyacinths, miniature daffodils, iris, and tulips—are easy to force. Large, fragrant hyacinths are also reliable. Always buy the largest, firmest bulbs you can find, free of nicks, bruises, or sprouted roots.

If the weather is still warm when you want to start, store bulbs in a mesh bag in the refrigerator’s vegetable bin (away from apples and other ripening fruit) for 2–3 weeks. Even with this pre-chill, bulbs still need time in a pot to develop roots.

Potting Up

Most bulbs thrive in a soilless potting mix. Start with clean pots and fresh mix.

1. Plan ahead. In autumn, purchase bulbs from a garden center, nursery, or mail-order source. Choose a pot at least twice as deep as the bulbs to allow for root growth. Fill half full with potting mix.
2. Place bulbs close together without touching. A 6-inch pot holds up to six tulips, three narcissus, or 15 minor bulbs like crocuses or grape hyacinths. For a dense display, layer different bulbs in the same pot—larger ones on the bottom, smaller on top. If their chilling and bloom schedules differ, plant them in separate small containers and combine when in bloom.

3. Cover bulbs with mix, leaving tips exposed. Water thoroughly. Label with name and date; loosely cover the pot with a paper bag. Place in cool (35–45°F), dark storage for chilling. See the timetable below for duration.
4. Check moisture periodically—keep soil damp but not soggy. When roots appear at the bottom and green shoots emerge at the tips, chilling is complete. Move pots to a warm room.

5. When flower buds form, move pots to a sunny spot. Keep soil moist. Once flowers open, move out of direct sun to prolong blooms. After flowers fade, discard bulbs (most forced bulbs won’t rebloom).

Growing in Water

Paperwhites and ‘Soleil d’Or’ can be grown without soil. Place bulbs in pebble-filled containers with the base touching water. They don’t require chilling but benefit from a cool temperature (50°F) until the top shoot is a couple of inches long, then move to a warm, bright area.

The needed chilling period is usually given as a range. Begin checking pots at the short end; move to warmth once shoots are 2–3 inches above the bulb.

As a general rule, start chilling in September for January bloom, October for February, November for March, and December for April. For precise timing, see the list below.

Chilling and Blooming Times

• Daffodils: 12–15 weeks chilling; 2–3 weeks to bloom after chilling.
• Tulips: 10–16 weeks chilling; 2–3 weeks to bloom.
• Crocus: 8–15 weeks chilling; 2–3 weeks to bloom.
• Grape hyacinth (Muscari): 8–15 weeks chilling; 2–3 weeks to bloom.
• Iris reticulata: 13–15 weeks chilling; 2–3 weeks to bloom.
• Snowdrop (Galanthus): 15 weeks chilling; 2 weeks to bloom.
• Hyacinth: 12–15 weeks chilling; 2–3 weeks to bloom.