How to force bulbs indoors during the winter
Forcing bulbs is essentially tricking them into thinking spring has arrived. Here’s what to know about forcing bulbs.
How to force bulbs indoors
Essentially the process is similar to the one outdoors, except you are planting the bulbs in pots, and simulating the old, dark winter conditions they need to grow. Here are the basics:
- Start by planting the bulbs in a shallow pot or bowl, using loamy compost with some added grit to allow for drainage.
- Be sure to place the bulb with the pointy tip facing up – slightly below the surface of the soil – then fill in the soil around it.
- Once the bulbs are potted, put the pots in storage in a cool, dark place. One option is to line a box or drawer with a heavy duty black garbage bag, place the pots in there, and then store in a garage, basement, cellar or shed. The key is to make sure it’s somewhere where the temperature doesn’t get above 50 degrees.
- Do a welfare check on your bulbs every few weeks, and water them lightly if they seem to be dry.
What is the timeline for forcing bulbs
Bulbs mostly need 12 to 15 weeks of pretend winter in cold storage in order to become sufficiently rooted and are ready to bloom. Some flowers need more cold treatment than others.
Examples of time length for different bulbs
- Crocus, iris reticulata, snowdrops: 15 weeks of cold
- Daffodils: 15 to 17 weeks
- Hyacinths: 11 to 14 weeks
- Muscari: 13 to 15 weeks
- Scilla: 12 to 15 weeks
- Tulips: 14 to 20 weeks
You will know that the bulbs are ready to come out from the cold when you can see roots at the bottom of the pot. Even if you see the plant start to sprout on top, if it doesn’t have visible roots, it’s not ready yet.
When the roots are there, give the plants some time to get used to the warmer climate, by placing them somewhere in your home that is cool and bright (and away from a heat source) for two or three weeks. In most cases, the bulbs will begin to bloom in two to five weeks.