Forcing bulbs for a whenever bloom

Credit: International Bloembollen Centrum Hillegom, Holland

For those who just can’t wait for spring-flowering bulbs to show their colours, here’s how to force bulbs to bloom earlier

It was the domestically inclined Victorians who brought the gentle art of forcing bulbs to the masses. In 1832 a nursery run by the Landreth family in London offered 50 different varieties of bulbs for sale—almost all of them destined for indoor decoration.

Today, forcing—inducing spring bulbs to flower before their natural flowering time—is a three-step process. You can do this anytime—you simply need to plant the bulbs, then simulate deep winter and early spring, says the Netherlands Flower Bulb Association.

Planting bulbs:

Fill a pot with about 8 cm (3-1⁄4 in.) of soil, then nestle into the soil as many bulbs as will fit in the pot without touching each other. Cover with about 2 to 3 cm (3⁄4 to 1-1⁄4 in.) of soil to about 3 cm (1-1⁄4 in.) from the top of the pot. (The exceptions are tulips and narcissus, which like the tops of their bulbs poking out of the soil.) Water generously.

To simulate winter:

Your pots of bulbs now need several weeks of cold and dark (see chart above). Most underground garages are ideal for this chilling period, however, make sure the pots do not freeze. Check the temperature of your garage and place the pots in a cardboard box to keep the light out. Inspect the pots weekly to see if they need watering. The soil should be moist but not soggy. If soggy, the bulbs will rot.

To simulate spring:

After the bulbs have cooled for the appropriate time period, or when shoots are 2.5 to 5 cm (1 to 2 in.) tall, move the pots to a cool 10° to 13°C (50° to 55°F) location inside the house where they are not exposed to direct sunlight (a north-facing windowsill is ideal). Keep them in this location until the shoots have greened up, leaves are showing and buds begin to appear.

Once buds are visible, you can place the pots wherever you like without worrying about providing light.

Tip:

If you’ve planted your bulbs in simple plastic pots, place them inside pretty containers to show them off to best advantage.

Crocus

Planting depth from top of soil: 2.5 cm (1 in.)
Cold, dark period 2–9°C (35–48°F): 12–15 weeks
Cool, light period 10–13°C (50–55°F): 2–3 weeks
        

Hyacinth   

Planting depth from top of soil: tops of bulbs out
Cold, dark period 2–9°C (35–48°F): 11–15 weeks
Cool, light period 10–13°C (50–55°F): 2–3 weeks

Hyacinth (pre-cooled)

Planting depth from top of soil: tops of bulbs out
Cold, dark period 2–9°C (35–48°F): 10–12 weeks
Cool, light period 10–13°C (50–55°F): 2–3 weeks

Narcissus

Planting depth from top of soil: 2.5 cm (1 in.)
Cold, dark period 2–9°C (35–48°F): 12–15 weeks
Cool, light period 10–13°C (50–55°F): 2–4 weeks

Tulips

Planting depth from top of soil: tops of bulbs out
Cold, dark period 2–9°C (35–48°F): 14–17 weeks
Cool, light period 10–13°C (50–55°F): 2–4 weeks

Scilla

Planting depth from top of soil: 2.5 cm (1 in.)
Cold, dark period 2–9°C (35–48°F): 10–12 weeks
Cool, light period 10–13°C (50–55°F): 2–4 weeks