Grow guides › Forcing Rhubarb
Forcing rhubarb: fresh stalks from January
Forcing means growing rhubarb in the dark and a little warmth so it sends up tender, sweet, bright pink stalks weeks before rhubarb in the garden. With a forcing crown bought from September onwards you can be eating your own rhubarb in the middle of winter.
- Buy & pot upSeptember onwards
- Bring into warmthAfter some frosts (Dec)
- Ideal temperature7–15°C
- LightNone at all
- First stalksFrom January
Forcing uses up the energy stored in the crown, so you need a big, strong crown – like our forcing crowns. A young rhubarb plant in a 9cm pot isn't ready yet: plant it in the garden and see our rhubarb guide.
Month by month
| September – November | Pot up your crown and leave it outside to get cold. |
|---|---|
| December | After a few frosts, move it into an unheated greenhouse, conservatory, shed or garage, and cover it. |
| January – March | Pick your forced stalks. |
| Spring | Plant the crown in the garden to recover. |
1. Pot up your crown
- Use a large pot or tub at least 30cm (12in) deep and wide – around 15–20 litres – with drainage holes. A sturdy bucket with holes drilled in the base works well.
- Fill with multi-purpose compost, ideally mixed with some well-rotted manure or garden compost.
- Sit the crown in so its buds are just at the surface of the compost. Don't bury them.
- Water well, then keep the compost just moist, never soggy.
2. Let it get cold first
This is the step most people miss. Rhubarb needs a spell of cold weather before it will wake up and grow strongly – it's how the plant knows winter has happened.
- Leave the potted crown outside from when you get it until it has had several frosts, usually by early to mid December.
- Don't worry about frost on the pot. The crown is completely hardy and the cold is doing it good.
A crown brought into the warm before it has had enough cold may sulk, grow weakly, or not grow at all. If you're unsure, leave it out a little longer – you won't lose anything.
3. Bring it in and cover it
- Move the pot somewhere sheltered and a little warmer: an unheated greenhouse, porch, conservatory, shed or garage. Around 7–15°C is ideal. Warmer is faster, but too hot gives thin, weak stalks.
- Cover the whole pot so no light at all gets in. An upturned bucket, a dustbin, a large cardboard box, or a black bin bag over a frame of canes all work. Block any holes in the cover.
- If the cover is light-coloured or you're in a bright conservatory, add an extra layer, such as an old blanket, to keep it truly dark.
- Check every week or so. Water only if the compost has started to dry out.
In the dark the stalks stretch up looking for light. They grow pale, tender and sweet, with small yellow leaves – exactly what makes forced rhubarb so special.
4. Pick your rhubarb
- The first stalks are usually ready about 4–8 weeks after covering, depending on how warm it is – so from January onwards.
- Pick when stalks are about 20–30cm (8–12in) long, or reach the top of the cover.
- Hold each stalk low down, twist and pull it away from the crown. Don't cut.
- Keep picking as new stalks come, for around 4–6 weeks, until they get thin.
- Cut off the small leaves and put them on the compost heap – the leaves are poisonous, only eat the stalks.
Forced rhubarb is so tender it needs only a few minutes' gentle cooking. Lovely stewed, in crumbles, or roasted with a little sugar and orange.
5. After forcing
Forcing takes a lot out of the crown, so give it a rest:
- Uncover it once you've finished picking and let it grow leaves in the light.
- In spring, plant it in the garden in rich soil (see our rhubarb guide), feed it, and water in dry spells.
- Don't pick from it for the next year or two, and don't force it again for at least two years. After that it will crop for years.
Problems
- Nothing happening after a few weeks: the crown may not have had enough cold, or it's too cold where it is. Be patient; it will often start once it warms a little.
- Thin, spindly stalks: too warm, or the crown is running out of energy. Move it somewhere cooler, or stop picking and let it rest.
- Green stalks and big leaves: light is getting in. Check the cover.
- Crown going soft or mouldy: the compost is too wet. Let it dry out a little and make sure the pot drains.