For those who can never get enough of tulips, daffodils, and spring bulbs, try potting them up to force into cheerful bloom this winter in the house. See our tips on how to force bulbs and a timetable for when to pot up different types of bulbs.
It is easy enough to do and you will be glad you did it when they start blossoming while there is still snow on the ground.
Temperature, moisture, sufficient cold period, and protection from rodents are the most important considerations. Some bulb varieties, like early single tulips, are easy to force. Many bulbs are now being marketed specifically for forcing and will say so on the label.
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Potting the Bulbs
Potting is the easiest part of this process and the messiest. I use shallow wide containers called bulb pans that are 5 inches deep and 8 inches across. Fill your pots half to three-quarters full of fast draining potting soil or a soilless mix. No fertilizer is necessary because your bulbs come packed with all the nutrition they need to produce this season’s flowers. Place them in the pot, pointy end up, as close together as you like. Don’t let them touch just in case one rots it won’t spoil the rest. A full pot gives a better display and you can mix varieties in the same container if you wish.
When planting tulips be sure the flat side of the bulb faces the pot rim because this is the side that will have the first leaf and it looks nicer draped over the edge of the pot instead of bunched up in the center. Cover the bulbs with soil to within an inch of the rim to allow room for watering. It is okay if large bulbs such as daffodils, tulips, and hyacinths have their noses sticking up out of the soil. Water the pots well and put them in a cold, dark, place to develop roots. Check the pots once a week and water when dry.
To get our flowering bulbs to bloom indoors we have to trick them into thinking winter has come and gone and it is safe to blossom.
Storing the Pots
The key to success is finding a place to store them that is accessible, cold enough, and protected from marauding rodents. Many books recommend digging a trench, putting the pots in there, and covering them with dirt or leaves. This will work in warmer climates. In the frozen north, however, you need to use a cold basement or unheated room that stays between 32 to 40 degrees. Most bulbs need 12 to 15 weeks of cold treatment before they are sufficiently rooted and ready to bloom. Check the bottom of the pots for roots. Even if they show some top growth but aren’t well-rooted, give them more time in storage.
Forcing the Bulbs
When they have rooted and their time is up, you can start bringing pots out of cold storage. To prevent “blasting” or shriveling of the flower buds, introduce them to the warmth of the house gradually by placing them in a cool bright spot away from any heat source for 2-3 weeks. Most bulbs will begin to bloom in 2-5 weeks.
Timetable for Popular Forced Bulbs
Here’s a timetable for some popular forced bulbs:
- Crocus, iris reticulata, and snowdrops need 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.
Did you know that you can also force branches of flowering trees and shrubs into bloom? See our article on forcing branches.
Robin Sweetser
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What do I do with bulbs once flowers have passed by when they were forced to bloom in winter
Hi Shirley, Water regularly until the foliage begins to yellow. At this point, gradually cut back on watering until the foliage withers and dies. Carefully remove the bulbs from the potting soil, allow them to dry for 1 or 2 weeks, then store the bulbs in a cool, dry location. Plant the bulbs in fall.
Why did my hyacinth bulbs all dry out while being chilled? This is first time I’ve tried to restart bulbs.
How were they stored? It sounds like they were stored in an area that was a little too dry.
my some gardening with a woman who did landscaping and got some seeds from her and they are labeled hyacinth, they are not in bulb form . do you know if they are worth trying to plant?
I knocked the plant over and it fell on the rug. This broke some stems and also one whole bulb came out of the planter without the roots. If I put it in a glass jar, will it grow roots. It said to pull off the dying bulbs so I pulled them all off. Did I kill the plant?
I bought a bulb in a jar that had already bloomed , should I go ahead and put into a pot, then transfer to the ground in spring. ? Also is it to late to get other bulbs going?
Thanks for your article. I have 4 bulbs in a glass far, and I am wondering when to put them outside. They already have roots and are in glass jars with water trying to bloom already.
