Forcing Bulbs Indoors
So, you know about Fall Bulbs: bright Daffodils, fragrant Hyacinths, adorable Crocus, and of course the rainbow of colours in the Tulip family! All of these stunning spring bloomers need 12 to 16 weeks of cold temperatures (aka fall and winter) which is why they’re available in September to be planted before the ground freezes. But that’s a long time to wait and the winter months can be so dreary, if only there was an earlier way to enjoy these beautiful flowers…oh wait, there is!
What is “Forcing” Bulbs?
The term “forcing” is used to describe the process of stimulating a plant to flower outside of its natural blooming season, sometimes weeks or even months ahead of schedule. For Fall Bulbs, this process is achieved by inducing a cold period — essentially, you’re tricking your bulbs into thinking that it’s April when it’s really December or January!
Why Should I “Force” Fall Bulbs?
Well, because they’re pretty! They’re a great way to brighten up a chilly winter day, and they make great holiday or mid-winter gifts for anyone who needs a little pick-me-up.
Note: Forcing bulbs is purely by choice. Plant your bulbs in the garden as usual and you’ll still be able to enjoy them come spring!
Do I Need Special or Expensive Equipment?
No! All you need for this process are bulbs (obviously), pots that are at least 6 inches deep and ideally with drainage holes, and a spot to keep them cold like a spare refrigerator or unheated garage. You can use pot covers or other clean containers that do not have any outlets for drainage, but you’ll have to add a layer of stones to the bottom and be very careful when watering most of your bulbs.
Do I Need a Separate Pot for Each Bulb?
No! Depending on the size of your pot and the type of bulb, you can place several together for a more lush display. You can even try layering different varieties in the same pot: tiny Crocus bulbs fit nicely overtop larger Tulips and Daffodils!
When Should I Start?
Each bulb species has its own timeframe when it comes to minimum cooling periods, plus an additional 2 to 4 weeks before flowers start to appear. Use the chart below to check your varieties’ individual cooling times:
Bulb Type Cooling Time (add 2 to 4 weeks for flowering)
Hyacinth 11 to 13 weeks
Narcissus (Daffodil) 12 to 15 weeks
Tulip 13 to 17 weeks
Crocus 14 to 15 weeks
Muscari (Grape Hyacinth) 14 to 15 weeks
So if you’re hoping to have Hyacinths blooming in time to give them as a Christmas gift, you’ll need to start the cooling process around mid-September. Fall bulbs can also “chill out” beyond their minimum cooling times, so you could have a running rainbow of blooms to enjoy through the winter!
How Do I Start?
1) Fill your pots with moist potting soil and plant your bulbs to their appropriate depth – check your packages for individual needs. Pre-moistening your soil means you don’t need to water your pots right after planting.
Note: Some bulbs can grow beautifully in just water! Use special Hyacinth vases to grow their fragrant blooms, or place Paper Whites in decorative stones to hold them upright. Be sure to keep the water level just below the bulb so that the bulb doesn’t rot and the roots can search for water.
2) Place your pots in a cool, dark environment that does not freeze, like a spare refrigerator or unheated garage. Your bulbs will need to stay chilled at around 9°C (50°F) for anywhere from 11 to 17 weeks (see that handy chart for help on timing).
3) Your pots will need to be watered periodically during their cooling times, but not to the point of being soggy. Check your pots at least once a week and water as needed.
4) Once you see pale shoots start to emerge it’s time to (slowly) introduce your bulbs to light and warmth. Place them in a cool but bright area, away from any heat sources, for 2 or 3 weeks and then slowly increase their exposure to sunlight and warm temperatures.
5) Your bulbs should start blooming a few weeks after coming out of their chill zones – enjoy!
6) After flowering, cut the flower stems and place your pots in direct sunlight; allow the foliage to keep growing until it naturally begins to yellow and die back. Do not pull the leaves off! As the plant withers (totally natural, trust the process) store your potted bulbs in a cool, dry area until late summer or early fall when you can plant them in the garden.