What to Eat: Food that’s good for your health, pocket and plate. Joanna Blythman

less perfect-looking roots at a cheaper price, but mainly they insist that growers supply only Grade One roots.

      Where and when should I buy root vegetables?

      Root vegetables are on offer year-round so it might not be obvious from looking at supermarket shelves but, in the natural run of things, they are more seasonal than you might think. There are winter and summer crops of both carrots and beetroot. Tender violet-white turnips are a spring pleasure. But other roots mature in autumn and although they do store well, they are best for winter eating. So if you are still eating parsnips in May – not a great idea – then you can be sure they won’t be home-grown.

      Will root vegetables break the bank?

      As a general rule, root vegetables are wonderfully cheap, but watch out for those – usually carrots – that have been processed or prettified to lend them ‘added value’. Expect to pay a premium for having your carrots washed or chopped, while baby carrots or slender new carrots are almost always an expensive disappointment. Supposedly superior carrots from named varieties cost many times more than the basic mature root and generally taste worse.

      You will also pay over the odds for small beetroots that are sold in bunches with their leaves still attached. Harder, larger, more mature beetroot are cheaper and will keep much better.

      As Jerusalem artichokes and celeriac have become trendy, supermarkets often sell them pre-packed or shrink-wrapped as boutique, speciality vegetables and charge accordingly. Look out for them sold loose, and for much less, in alternative outlets.

      There’s no rush to use up root vegetables: they keep well for ages, irrespective of the limited longevity suggested by their use-by date. If they have softened, pare off any yielding bits until you get to a firm core, then use it chopped in recipes such as soup, gratins, stews and purées, where the vegetable is well cooked, not served raw.

      Celery

      Celery packs more punchy flavour than any other vegetable, although, served raw, it isn’t to everyone’s taste. Its ubiquity on our shelves is explained by the fact that it is cheap, keeps well in the fridge and can be relied on to lend a welcome juicy crunch to salads. What is often overlooked is that celery can be a wonderful vegetable once cooked, when its potential brashness gives way to more interesting flavours reminiscent of those we associate with highly desirable vegetables, such as asparagus or artichokes. It merits a bigger role in cooking than being used just a stalk at a time as a minor aromatic.

      There are two ways to present celery successfully. Either serve it raw, preferably chopped very, very small, or so well cooked that you can cut it with a fork. Anything in the middle can put people off this vegetable for life.

      Celery comes in two types: the more common, stronger-flavoured green one and the less available white one. Snap up the paler white celery when you see it. It has a superior, subtler taste than the green sort: sweeter, nuttier and with aniseed notes. Many people find the fibrous threads that run down the outside of celery stalks unpleasant and spoil their enjoyment of the vegetable, but these are easily and quickly removed using a potato peeler. The inner stalks and heart of celery are less fibrous.

      Things to do with celery

      • Make a classic Waldorf salad of finely chopped celery, sweet apple and walnuts, bound with equal amounts of mayonnaise and soured cream or natural yogurt. Add leftover chicken to make it into a substantial, portable lunch.

      • Celery makes a subtle, elegant, eau-de-nil-coloured soup. Just let it sweat with onions for a long time, then add chicken stock or vegetable bouillon. Liquidize, sieve and finish off with cream and parsley.

      • Along with carrots and onions, celery is an essential component in the classic French mirepoix and Italian soffrito, those gently sweated mixes of finely chopped vegetables and aromatics that are used as a flavour base for many dishes. Use this to start off a Bolognese-style ragù, stew or soup that will be liquidized, and taste the difference.

      • Slice it razor-thin over a bed of watercress or rocket, dress with olive oil, lemon juice and lots of black pepper, then crumble over a salty, mature, cheese such as Parmesan.

      • Braise it long and slow with chicken stock and cream. This goes brilliantly with roast chicken and provides a creamy gravy.

      • For a cheaper – and much more interestingly textured and flavoured – tuna or egg mayonnaise, add very finely chopped celery.

      • Cut into batons, you can eat it with Middle Eastern-style dips as a healthier alternative to pitta bread.

      Is celery good for me?

      Celery is an excellent source of vitamin C, which boosts the immune system and may be protective against heart disease and cancer. Celery also has useful amounts of soluble fibre, which slows down the rate at which sugar is released into the blood; vitamin B6, which is necessary for metabolizing the amino acids in protein and the formation of red blood cells; potassium, which helps regulate blood pressure; and folate, which helps prevent birth defects. Green celery contains more vitamin C and folate than white.

      In many types of traditional medicine, celery is recognized as lowering blood pressure. This may be due to its richness in minerals such as potassium, but also to the presence of plant compounds called phthalides, which may help relax the muscles around arteries and allow them to open up. Celery has a history of usage as a treatment for nervous conditions as it is thought to have a calming effect.

      Celery is generally accepted to have a diuretic effect; that is, increase the production of urine. Some research suggests that this property may encourage the elimination of excess fluid in the body and possibly help reduce the severity of inflammatory joint problems, such as gout and rheumatoid arthritis. In many countries, celery is regarded as a cleansing vegetable with tonic properties.

      Some research has identified certain natural plant compounds in celery – acetylenics, phenolic acids and coumarins – which may help prevent cell damage and inhibit the development of cancer.

      UK government tests conducted in recent years identified a problem with residues of an insecticide in celery that is known to be toxic to wildlife and can have adverse health effects for people heavily exposed to it. The maximum residue limit for the insecticide in question has been tightened. The latest results of testing, however, still show that almost half of all celery samples contained residues. So it is a good idea to buy organic celery whenever possible. Pesticides are not used in organic celery production.

      A BRITISH TRADITION RIPE FOR REVIVAL

      White blanched celery, grown as an autumn and winter vegetable, is a great British speciality. Its production is mainly centred in the Lincolnshire Fens, Lancashire and Bedfordshire. Less is grown now than in the past, as the earthing-up of soil is quite labour-intensive, which adds to the grower’s costs. It is also a crop that is susceptible to frost. Many consumers find the appearance of green celery more attractive and assume that it is fresher and healthier, which isn’t necessarily true. For all these reasons, this once distinctive British-grown vegetable has been pushed off the shelf by a steady, year-round supply of green celery grown in warmer countries, mainly Spain. But seasonal white celery, with its less one-dimensional flavour, is ripe for a revival.

      How is celery grown?

      The traditional way to grow celery is to cultivate plants from seed in a greenhouse, then transplant them into deep trenches where they are earthed up to blanch them. Keeping the heads out of the light reduces the amount of chlorophyll in the stalks and leaves, and produces white celery that is pale and tender with a more nuanced flavour than green. More commonly these days, however, celery is grown above the ground like other crops and sold green. White or green, it is cut by hand.

      Where and when should I buy celery?

      Green celery, usually imported, is always on sale. White and green British-grown celery is a seasonal treat to snap up from the end of September until the end of December.

      Will celery break the bank?

      Celery is extremely affordable. Organic celery is consistently one of the lowest-priced organic vegetables you can buy.