How To Force Bulbs To Bloom In Winter
Enjoy an early spring by forcing plants to flower indoors during winter.
Grown in pots and put outside, bulbs will flower at the same time as they would if they were growing in a garden bed or border. But you can make them bloom earlier and cheer the midwinter gloom.
GROW TIP When planting several bulbs in one pot, position them close together but make sure they’re not touching.
Plants you can force to bloom out of season
Tulips, hyacinths, crocuses, freesias, snowdrops, jonquils and daffodils can all be forced to bloom out of season.
Tulips. Image: Thinkstock
Create a display
Choose early flowering varieties and plant them in autumn.
The bulbs should start flowering 12-15 weeks after planting, depending on the type. Hyacinths and narcissi take about 12 weeks, and others a little longer.
For a continuous show of blooms throughout winter, plant up pots at 2-3 week intervals.
Plant in pots
Use a specialised bulb potting mix to grow them in pots indoors.
SPREAD a generous layer of damp potting mix in a pot. Add the bulbs, fill around with mix so the tips just show, then firmly press down the mix.
COVER the pot with a black plastic bag and position it where the temperature will stay cool such as a shed, cold frame or garage.
CHECK how the shoots are developing and that the mix doesn’t dry out.
BRING them inside when the shoots reach 25-50mm and keep in a cool place out of direct sunlight until the shoots turn green, then move to a lighter spot.
MOVE to the flowering position when the buds show, preferably a bright area where the temperature doesn’t exceed 20°C.
WATER as needed and feed weekly with a high-potash indoor plant fertiliser.
GROW TIP To support the flowers as they open, insert thin canes around the edge of the pot.
Use a specialised bulb potting mix to grow them in pots indoors
What to do when plants finish flowering
Deadhead when the blooms start to fade but leave the stalks intact. Move to a cold frame, continuing to water and feed with a high-potash fertiliser until the leaves yellow.
Forced bulbs shouldn’t be used a second year as house plants. Store them in a cool, dark place over summer and plant them in the garden in autumn.
While most bulbs will flower outside in the first spring after they have been replanted, don’t expect a spectacular display.
Deadhead when the blooms start to fade but leave the stalks intact
How to choose bulbs
When choosing bulbs, select only those that are heavy and firm. If the bulb feels light, then it could be dead inside. If it’s soft, it may have a fungal disease.
Tulip bulbs, in particular, need an intact outer skin to prevent dehydration and damage.
Grape hyacinth bulb
How to raise bulbs in water
Grow a single bulb in a vase of water to create a long-lasting fragrant floral display for any room in your home.