Apium graveolens var dulce, commonly known as celery, first became popular as a vegetable in Italy in the 17th Century, although wild celery was used as a herb and medicinal plant in Ancient Egypt, China, Greece and Rome. It has a distinctive crunchy texture and strong taste, but is perhaps most well-known from the legend that says it takes more calories to eat celery than it contains.

Celery has about 15 calories per 100 grams and, even though it is relatively difficult to eat, chewing does not use many calories per hour so the statement is unlikely to be true.

Nevertheless, celery is nutritious, containing a variety of vitamins and minerals¹, so is worth eating. In particular it contains phthalides, which are compounds that reduce stress hormones and relax arteries in the body, so was used traditionally as a medicine to treat high blood pressure. Celery is also a diuretic and laxative. Ancient Romans ate it as an aphrodisiac, and if they had a hangover they might wear a stick of celery round the neck as a cure. Eating the celery rather than wearing it, or drinking celery juice, could be other ways to combat a hangover.

The phthalides also make celery good as a flavour enhancer when used in small amounts in recipes such as spaghetti bolognese, chicken soup and many more. Some people are allergic to celery, experiencing symptoms ranging from mild (blisters in the mouth) to severe (anaphylactic shock) when they consume this vegetable. Since 2005, labels on prepared food have had to indicate whether celery has been used as an ingredient.

There are three main types².

• Leaf, Cutting or Soup Celery - the easiest type to grow, being very hardy with many thin stems and plenty of leaves that are ideal for using in soups³.

• Trench Celery - the hardest to grow, although the most popular eating varieties are of this type as they are the most flavoursome (provided they are grown well). Ideal for gardeners who like a challenge.

• Self-Blanching Celery - less hardy than the other types, with less flavour, but easier to grow than Trench varieties.

For most vegetables, such as asparagus, blanching just means depriving the plants of light in order to make them grow white. Celery is blanched by keeping the stems cool and moist as well as in the dark so that they grow more succulent and tasty without being stringy. Celery varieties can be red or green as well as white.

Growing Celery

Celery is biennial⁴ so all types are grown from seed. Best results are achieved by sowing seeds in mid to late spring and keeping them at 13-16°C in a greenhouse.

Once two cotyledons⁵ and two leaves have developed, the seedlings can be potted up into larger cells or individual pots and hardened off⁶ before planting outside when they have about six leaves. If the plants are larger than this, they can still be planted out, but the top leaves should be removed first, to reduce transplanting shock.

All the types require rich soil which is kept constantly moist. Covering the soil with a layer of straw or garden compost once the plants are established helps with water conservation as well as weed suppression, so you can avoid disturbing the roots and stems. A general-purpose fertiliser should be applied around four to six weeks after planting out.

Leaf Celery

Several leaf celery seeds can be sown into one cell of a planting tray and, when they are ready to be planted out, the cells should be spaced 20cm (8in) apart. Stems can be harvested regularly from about five weeks after planting outside.

Self-blanching Celery

A little bit more of a challenge to grow. In Spring, prepare the ground where the celery is to be planted by digging in plenty of well-rotted manure or garden compost. Seeds should be sown individually into cells of a planting tray, so that the roots are not disturbed too much when the seedlings are planted out.

Spacing the cells at 27cm (11in) intervals produces the longest stems, but closer planting results in a larger number of shorter, thinner stems. The base of the plant should be at soil level, and not buried with the roots. Surrounding the outer stems of the established plants with straw protects them and improves the flavour and texture of the stems. The whole plants can be lifted from the ground from around 20 weeks after planting out.

Trench Celery

So you've had enough of soup and want more flavour than self-blanching celery can offer, but are you ready for the challenge of growing trench celery?

The work begins the year before - the trench should be dug in late Autumn. It should be 30cm (12in) deep and 38-50cm (15-20in) from front to back. The plants will be spaced 30-45cm (12-18in) apart, so the trench should be as long as necessary to accommodate all the plants you plan to grow.

Use a garden fork to break up the soil at the bottom of the trench and ensure good drainage, then add a generous layer (7-10cm (3-4in) deep) of well-rotted manure. Top up with soil until the trench is just 7-10cm (3-4in) deep and then leave it to settle until Spring.

Grow your seedlings as for self-blanching celery. A week before they are ready to be planted outside, dig some general-purpose fertiliser into the soil in the trench. As with self-blanching celery, the crown (at the base of the stems) should not be buried. The trench should still be 7-10cm (3-4in) deep when all the plants are in. Let the plants grow on until they are 30cm (12in) high.

Now the blanching process commences.

Step one is to loosely tie the stems together, just below the leaves, with string or raffia, water the soil around the plants thoroughly and then fill the trench to ground level with more soil.

Step two takes place three weeks later. Water the soil, then mound the moist soil around the plants to a height of 7-10cm (3-4in) above the previous soil level. Make sure no soil falls into the heart of the plant, otherwise it will rot.

Repeat step two every three weeks until the stems are completely covered, with only the leaves showing above ground.

Alternatively, cover the stems with loose collars made from drainpipes, plastic bags (lined with paper to prevent sweating), newspaper or corrugated cardboard. Every three weeks, replace the collar with a longer one and check for slugs and other pests each time.

Depending on the varieties chosen, the plants can be harvested from October through to February (the leaves should be protected with fleece or straw during Winter if frost is expected).

Troubleshooting

Slugs are a pest for many plants, celery included, and carrot fly larvae are partial to it as well as their usual carrots⁷, but there are three main things to look out for that are specific to this plant.

• Celery fly - the celery fly maggots tunnel through the leaves of young plants, creating blisters. Seedlings showing signs of this should be discarded. In more established plants, affected leaves should be pinched out and destroyed.

• Celery Leaf Spot - a fungal disease causing yellow or brown spots to form on the leaves. Buying seeds that have been treated will prevent this, but if a plant becomes affected, the discoloured leaves should be removed and destroyed.

• Bolting - the plant produces a flower stalk rather than a crop of edible stems. This can result if the seeds are exposed to cold temperatures, or if the seedlings get transplanting shock, or if the established plants do not receive enough water. Controlling the temperature of the environment where the seeds are sown helps, as does planting seeds in individual cells of propagating trays and trimming the leaves if they have grown too large before being planted out. The plants should also be kept well watered, particularly when no rain is forecast.

Careful cultivation and keeping an eye on the leaves will reduce the risk of problems and result in a decent crop at the end of the year.

Storage

Cutting celery can be harvested when required, but for Trench and Self-Blanching celery the whole plants are lifted from the ground when they are ready. The plants can be stored for several weeks in a frost-proof shed or other cool, dry place. Cut stems last for around three days in the fridge, or longer if they are scrubbed clean of dirt, wrapped in foil or a damp tea-towel and kept in the salad drawer.

The stems can be frozen, although they should only be used in cooked dishes once defrosted as the texture will have changed. For best results, cut the stems into approximately 2½cm (1 in) lengths, boil in a pan of water for three minutes, leave to cool, drain the water, transfer the stems into a freezer bag or other suitable container and put in the freezer.

If you want to cheat* and simply buy some celery from a supermarket or grocer's, make sure that the base is not brown, the stems are firm but not woody and any leaves are not wilting.

Eating Celery

Celery is perhaps most popular eaten raw. The outer stems, leaves and base (heart) are better cooked, so should be removed and saved for later. Clean the inner stems thoroughly to remove any soil particles, chop into pieces of the required size and enjoy.

The sticks can be eaten with dips, or filled with cream cheese or similar, and celery is a key ingredient in Waldorf Salad.

There are a variety of cooked dishes that involve celery - you can add stem pieces to casseroles and pies, for example, or choose a recipe that has celery as its main ingredient.

Braised Celery Hearts

Ingredients

• Celery hearts (as many as you want)
• Vegetable stock
• Vegetable oil
• Garlic, herbs, salt and pepper to taste.

Method

Heat the oil in a pan and sauté the hearts until they are golden brown. Drain off any excess oil and add enough vegetable stock to half-cover the hearts in liquid. Simmer for 30 minutes. Leaving the hearts in the pan and keeping them warm, pour the stock into a saucepan and boil until it reduces to a quarter of the original amount and thickens up. Pour the reduced stock back over the celery hearts and serve as a vegetable accompaniment to a main meal.

Cream of Celery Soup

Ingredients

• 350g (¾lb) celery
• 1 small onion
• 1 potato
• 570ml(1 pint) vegetable stock
• 25g (1oz) flour
• 25g (1oz) butter or margarine
• 280ml (½ pint) milk
• Herbs, salt and pepper to taste.

Method

Wash and chop the vegetables, and boil them in the stock until they are tender. Meanwhile, melt the butter and stir in the flour to make a smooth paste. Put the paste, vegetables, stock, milk, herbs, salt and pepper in a blender and process until the soup is well mixed. Reheat and serve.