Forcing Bulbs Indoors: Flowers in January if You Start Now

Forcing means persuading a bulb to flower out of season indoors. It is the easiest gardening project there is, it costs very little, and the payoff arrives in January when there is nothing else to look at.

The only difficulty is timing, and that is arithmetic rather than skill.

The two groups

Bulbs that need chilling. Hyacinth, tulip, daffodil, crocus, muscari. These come from climates with cold winters and will not flower without a cold period that mimics one. Skip it and you get leaves and no flower.

Bulbs that do not. Paperwhite narcissus and amaryllis. Both are from warm climates and flower without any chilling. Plant, water, wait.

If this is your first time, start with paperwhites. Six weeks from planting to flower, no refrigerator involved.

The timetable

1. Paperwhites. No chilling. 4 to 6 weeks from planting to bloom. Plant in mid-December for Christmas, or stagger every two weeks from October for continuous flowers.Easiest
2. Amaryllis. No chilling. 6 to 10 weeks. Plant in October for Christmas, allowing the longer end.Easy, dramatic
3. Hyacinth. 10 to 13 weeks chilling, then 2 to 3 weeks warm. Start chilling in early October for January flowers.Strongly scented
4. Crocus and muscari. 8 to 15 weeks chilling, then 2 to 3 weeks warm.Small and cheerful
5. Daffodil. 12 to 15 weeks chilling, then 2 to 3 weeks warm.Reliable
6. Tulip. 14 to 20 weeks chilling, then 2 to 3 weeks warm. The longest and the fussiest.Hardest

Work backwards from when you want flowers. For hyacinths in mid-January, chilling needs to start in the first week of October.

How to do the chilling

Plant the bulbs in pots first, in ordinary compost, with the tips just showing above the surface. Water lightly.

Then put them somewhere dark at 2 to 9°C, or 35 to 48°F. An unheated garage, a cold shed, a cellar, or the refrigerator. Check every couple of weeks and water just enough to stop the compost drying out completely.

Keep them away from apples and other ripening fruit. Fruit releases ethylene gas, which kills the developing flower inside the bulb. A bag of apples in the same fridge will give you a pot of leaves. This is the single most common way home forcing fails.

When shoots reach about 5cm and you can feel roots at the drainage holes, bring them into a cool dim room for a week, then into full light and normal warmth.

Paperwhites, the shortcut

These do not need soil either. Put a layer of pebbles or glass beads in a bowl, sit the bulbs on top, and add water until it just touches the base of the bulbs and no higher. Roots find the water, the bulb stays dry, and it does not rot.

Bright light and cool temperatures once growing. They flower in four to six weeks.

The known problem with paperwhites is that they grow tall and flop. There is a genuinely well-established trick for this: once shoots are about 5cm, replace the water with a solution of roughly one part clear spirit such as gin or vodka to seven parts water. The mild alcohol stress stunts stem growth by about a third without affecting the flowers. It sounds like a joke and it works, and it was tested properly at Cornell.

Amaryllis

Plant with the top third of the bulb above the compost, in a pot only slightly wider than the bulb. Water sparingly until growth starts, then normally.

Turn the pot every few days or the flower stalk leans hard towards the light and topples. Cooler rooms make the flowers last considerably longer.

Amaryllis is toxic to cats and dogs, and the bulb is the most concentrated part, so keep it off floor level if you have a dog that digs.

Afterwards

Forced bulbs have spent everything. Tulips and hyacinths that have been forced rarely flower well again and are usually composted.

Daffodils and crocus can be planted out in the garden after the leaves die back naturally, and will often recover over a year or two.

Amaryllis is the exception and is worth keeping. Cut the spent flower stalk, keep the leaves growing and feed through summer, then give it a dry rest in a dark place for eight to ten weeks in autumn before starting again.

If you have inherited bulbs with no label, the difference between a daffodil and a tulip bulb matters a great deal here, since one needs fourteen weeks of chilling and the other twelve. Photograph them and Identium will tell you what you are holding before you commit to a timetable.