Forcing the early shoots of Spring

Forcing Chicory

It is understandable that in the depths of winter, with a global market now on our doorstep, we turn to warmer climes for our fresh produce.  Even many home gardeners don’t bother much with winter produce.   Yet home produce at this time of year does not have to be all swedes and cabbages.

The close of the Victorian era marked the zenith of the kitchen garden in the UK.   Following the abolition of glass tax in 1845 and the development of plate glass just three years later, greenhouses were built against the south facing walls of the garden, heated by coal, which was still plentiful.  By this means wealthy Victorians, and even those of comparatively modest means, were able to enjoy many of the exotic fruit and vegetables that they had discovered whilst travelling the Empire.

The First World War put an end to this forever.  Whilst we will never return to the labour intensive gardens and heated greenhouses of Victorian times, there are nonetheless some aspects from that period worth reintroducing.  In this article I look at forcing, which not only protects plants from the cold but also excludes light, a combination of factors that encourages plants to produce early tender shoots.

The history of forcing

Forcing was not a Victorian invention but they certainly popularised the practice. Who knows exactly when it was first discovered that where the tide and wind cause shingle to pile up around our native seakale tender shoots would eventually force their way through?  Certainly the Italians were growing seakale under cover in the Middle Ages and its delicate flavour was known to John Evelyn in Britain when he wrote Aceteria in 1699.  By the early decades of the 18th century it was being widely grown in English gardens, transferred there from its natural habitat.  For quite some time after it had been domesticated, people living close to the sea, particularly in Sussex and Hampshire, also continued to help nature along by piling sand and stones around the plants on the sea shore so that they could harvest it for market.  So popular was this, that it became illegal to harvest the plant in the wild in order to preserve depleted stocks.  There is scarcely a single gardening book from the Victorian era that does not devote considerable space to the art of forcing seakale.  A pre-Christmas crop could be obtained by forcing them close to the pipes of a heated greenhouse.  Unheated outhouses provided the next crop and the final early spring crop came from outdoor plants, covered by terracotta pots, which were surrounded by horse manure or straw to increase their temperature.

Discovering to which other plants forcing would be beneficial seems largely to have been an accidental process.  Rhubarb, brought to Britain from Siberia and grown at the Chelsea Physic Gardens for its medicinal benefits, is thought to have been accidentally forced when a crown was covered with leaves by a gardener in the early 1800s.  Belgian Witloof Chicory is the result of a remarkably similar story.  The wild Chicory plant was grown at the Brussels Botanical Garden when, in 1850 and, again probably by accident, some stored roots were covered and sprouted what we now call chicons – tight heads of white leaves.   The technique has however subsequently been deliberately employed in Italy with several of their red leaf chicories.  The great benefit for chicories being that the exclusion of light prevents the formation of chlorophyll, which causes the leaves to become overly bitter.

Forcing Commercially

On a commercial scale, the principle stumbling block today is the heat required to bring about an early crop.   Rhubarb, an important food source to Britain in the winter months, was grown commercially from around 1830, in the “Rhubarb Triangle” formed between Bradford, Leeds and Wakefield.  The heavy clay soil here suited this Siberian plant, and there was plenty of fuel in the area, both as a bi-product from the wool trade and also from coal mining.  The area also benefitted from excellent transport links to get the rhubarb to markets, particularly in London and Scotland.  Initially these transport links were provided by canals, then came the railways and today with motorways.  This area continues to produce most of the rhubarb sold in Britain, but the number of growers is down to only a dozen and when the current huge heated sheds need replacement the number is likely to dwindle further.  However, there is hope that heating from wind-turbines might provide a way forward.

Seakale production has all but died out on a commercial scale.  Just one grower remains – Sandy Pattullo in Argyll.  The previous main grower, Paske’s of Lincolnshire, found it uneconomic to continue. The decline of seakale is especially sad because it is a real delicacy. Seakale is sometimes called Winter Asparagus, presumably because it is cooked and eaten in a similar way, usually with nothing more than melted butter.  The taste is, however, far more delicate than asparagus and perhaps more akin to Globe artichokes.

There is one large scale UK grower of chicory – based in Lincolnshire.  Several of the Italian Radicchio’s are however registered under the Protected Food Names scheme, so that, although they would grow well here, what you see for sale has usually been imported.

Forcing Domestically

Whilst commercial forcing has its difficulties, all of the above forced plants would be a valuable addition to the domestic garden in winter.    You don’t even need a greenhouse.   The first principle to understand is the difference between forcing in situ and uprooting the plants for forcing in a warmer environment.  Forcing is draining on a plant even when not uprooted, but when this is added to the equation, the plant is spent following forcing. For example, with commercially forced rhubarb, the crowns grow outdoors for a couple of years until they are strong enough for forcing and  are then dug up and replanted indoors where they crop for just one season.  For domestic growers, although still needing to allow the plant to establish before forcing, because this is usually done in situ, the plant will recover and can then be forced in alternate years.  In this way, the crown will last for around 10 years.  Exactly the same is true for seakale forced in situ.

Forcing pots, although expensive, are ideal for rhubarb and seakale.  Old chimney pots covered with a tile make a good substitute, although nowadays these are likely to be just as expensive.  An upturned bucket or dustbin will do the job, albeit less aesthetically, and you will also need to weight them down to prevent them blowing away.

The Chicory family (including radicchio) are most often transplanted even in a domestic situation.  The Italian red chicories, e.g. Trevise, will however withstand temperatures several degrees below freezing, so forcing in situ is an option.  Belgian Endive (Witloof) ideally needs a temperature of around 10˚C for forcing, but until that time the roots, which are dug up at the end of the summer, can be stored flat in a box covered with sand.  I then plant them in 8″ pots (as close together as will fit) and bring them inside to utilise the heat already there.  A cupboard is ideal, as it will also be dark, but the pots should also be covered, either with an upturned pot of the same size (drainage holes blocked) or within a black refuse bag.  They take about 4 weeks to grow large enough for cutting, so a succession of four pots will give you a weekly supply.

Recipe Suggestions

See here for suggestions for serving Seakale, Chicory and Rhubarb.

Useful Contacts

Chicory & Radicchio

Radicchio seeds:

Witloof: more widely available including Garden Organic


Thongs (Crowns): Garden Organic (0845 1301304 Jekka’s Herb Farm

Otter Farm

Forced shoots: Sandy Pattullo of Eassie Farm, Glamis, Argyll sells only on a wholesale basis but you may obtain from


Timperley Early is a widely available variety dating from the 1920s, which has an excellent flavour and is particularly well suited to forcing.  If you are looking for an older or more unusual variety Brandy Carr Nurseries ( 01924 291511) near Wakefield have over 100 varieties.

2 thoughts on “Forcing the early shoots of Spring

  1. I have a qtiuaty of old plastic pots and trays. I am happy to clean and package them into plastic bags and deliver them to a local collecting point. Do you know of a suitable collecting point around the Selby-York area? Selby District do not support plant pot recycling and such material is dumped into land fill which I do not agree with. Interesting to hear your your comments. Thank you, Regards, G.Neal

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