The tomato, Lycopersicon esculentum, is a plant of the potato family, native to South and Central America, where it was first cultivated well over 1,000 years ago.

They were brought to Europe by explorers such as Christopher Columbus and Hernando Cortez in the 16th Century. However, although they quickly became popular in the Mediterranean countries, they were treated with suspicion in Britain, and people thought they were poisonous. They were often treated as weeds and their fruit known as 'wolf apples' or 'wolf peach' to denote this more sinister aspect. Indeed, its genus name 'lysopersicum' translates directly as 'wolf peach'. For this reason tomatoes did not become generally accepted in Britain until the 19th Century. The French , on the other hand, believed that tomatoes had aphrodisiac properties and called them pommes d'amour or 'love apples'.

Fortunately, a few people in Britain realised that tomatoes were perfectly edible and focused on finding ways to add the tomato to their cuisine and, in the 19th Century, commercial tomato cultivation began. This coincided with the ability to produce sheet-glass on the large scale, thus facilitating the building of the first glasshouses in Kent and Essex.

Nowadays, many thousands of varieties of tomatoes are available and, indeed, tomatoes are now the most widely grown 'vegetable' in the world, being cultivated as far north as Iceland and as far south as the Falkland Islands.

Scientists have even grown tomato seedlings in space to study the effects of micro-gravity; and tomato seeds have been allowed to circulate the Earth for six years in a satellite to study the effects of increased solar radiation. No significant differences have been observed between these and 'control' plants and seeds kept on Earth.

Once people's suspicions waned these red fruity-vegetables began to be incorporated into much of today's cooking; and people began to concern themselves with more prosaic issues such as:

• 'It's a vegetable, because it isn't sweet.'
  'No, it's a fruit, because scientific classification says so.'

• You say, 'To-MAY-to.'
  And I say, 'To-MAH-to!'

Although botanically a fruit, their low sugar content leads them to be treated as a vegetable. Tomatoes are usually red when ripe, but yellow varieties are also common. The so-called cherry- and pear tomatoes are also grown on a small scale.

Tomato Classification

Tomatoes are divided into two main groups - determinate and indeterminate. Indeterminate tomato plants, which include large salad tomatoes, beefsteak tomatoes, and certain cherry tomato cultivars, keep growing and producing fruit until the first frost makes them stop. They are viney and need cages and/or stakes to keep them from sprawling all over the ground. Determinate tomato plants, such as the yellow pear tomato and many other small tomatoes, are neat and bushy. They produce one large group of fruit and then stop growing for the year. Determinates rarely need to be staked or caged, but it helps for them to have something to lean against as they grow.

Tomato Cultivation

In Britain tomatoes are usually grown under glass; planted from February onwards, they fruit until late October. Seeds may be sown in April, when the crop lasts until September.

For all tomatoes, there are some very simple growing tips:

• Tomatoes need a well-manured soil

• You should not start feeding the plant until you can see the tiny green fruit on the lowest flower truss. If it is done earlier, then you will get too much growth of stem between the fruit masses.

• Watering should be limited until two flower trusses have set

• After this, the plants should be given a good soak with water every day. It is essential that the soil is kept moist and the plants must not be allowed to alternate between wet and dry conditions. Failure to do this will result in tomatoes with split skins.

• Supporting sticks may be necessary and the plants should be spaced 36cm apart and pruned to a single stem.

• Early and regular removal of all the side-shoots that grow from the leaf axils on the main stem, or even direct from the bottom of the plants at ground level, is essential.

• The plants should be kept in full sun for at least six hours a day, especially when they are young.

• Bring the plants indoors when the temperature rises above 32°C or falls below 13°C. Extremes of temperature cause blossoms to drop off the plant.

• During the fruiting season the soil should be given a top dressing of general fertiliser. Regular and correct quantity application (as explained on the feed container) is important. Sporadic application of fertiliser is, in fact, worse than not feeding at all. Don't use too much nitrogen fertiliser; you'll get plenty of pretty leaves, but little fruit!

• Once you have 3 or 4 tresses of fruit, you should nip out the top of the plant to concentrate the plant's energies into maturing that quantity of fruit.

• When the fruit is fully formed the leaves should be removed to assist ripening.

• As one approaches the end of the season, say the third week in September, one is interested in getting as much naturally-ripened fruit as possible. Although it is possible to ripen them artificially, such fruit are not as flavoursome as those that have been allowed to ripen naturally. To this end, it is necessary to give them additional potash fertiliser. Although this is present in tomato fertilisers, some additional potash does help to speed up the ripening process. Hence give each plant a teaspoon of potash weekly and water it in.

• Don't plant tomatoes near walnut trees as these produce a chemical that causes tomato plants to wilt¹.

Pests and Diseases

Tomatoes are susceptible to attack by a variety of pests and diseases. 'Damping off' of seedlings can be prevented by using sterilised soil and pots and clean water. Leaf mould can be prevented by reducing humidity by adequate ventilation of the greenhouse, especially at night. Diseased areas should be cut out. Various chemical sprays are available to kill pests such as the red mite, Tomato Moth caterpillar and White Fly. No cure has yet been found for the mosaic and streak virus diseases. Affected plants should be destroyed. Virus-infected plants may be recognised by their leaves being mottled and curled, their stems may bear dark vertical streaks, and their foliage may be thin and distorted and growth may be stunted.

Nutrition

Tomatoes are excellent sources of vitamins A, C and E, and of lycopene. They are low in calories, typically containing only 14 calories per 100g. They contain virtually no fat and no cholesterol.

Lycopene

Lycopene is a carotenoid² that is responsible for the red colour of tomatoes³, watermelon and pink grapefruit. The redder the tomato, the more lycopene is present.

Hailed as a 'wonder chemical'⁴, it is an anti-oxidant which, once absorbed into the body helps to prevent and repair damaged cells by inactivating free radicals in the body. As such, it has also been credited with reducing wrinkles, which are also caused by free radicals which age the skin.

Numerous studies suggest that people who have the highest levels of lycopene in the blood are at much lower risk of developing various forms of cancer, including prostate, cervical, bladder and pancreatic cancers. Lycopene also appears to be protective against Age-Related Macular Degeneration (ARMD) - the most common form of blindness for elderly people in the western world.

Experiments conducted in the USA show that lycopene may be protective against endometriosis, a painful womb condition in which cells normally found in the lining of the uterus attach themselves to other parts of the pelvic area, causing scar tissue called 'adhesions', pain and inflammation. The condition can affect female fertility. Currently incurable, the condition is said to be affecting some two million British women, including the singer Louise Redknapp and the TV presenter Anthea Turner.

The typical daily intake of lycopene for a British adult is said to be less than 1mg, this being 25 times less than the amount found by studies to be protective against endometriosis. Experts say that eating one tomato a day, drinking 8oz of tomato juice or 150g of pasta sauce is enough to raise lycopene levels in the blood. It is also possible to purchase lycopene tablets.

Lycopene is more easily absorbed by the body after processing, for example into tomato ketchup or puree, and when tomatoes are cooked with certain oils, such as olive oil. Canned tomatoes have a little less vitamin C than fresh, but levels of vitamin E are the same.

Some Popular Tomato Varieties

Obviously one would like to achieve the maximum yield of tomatoes in a growing year, and therefore would have some greenhouse-grown plants, and some grown out-of-doors.

One of the most commonly grown varieties is 'Moneymaker', but this has a disappointing bland taste.

For growing out-of-doors, one should have a variety that crops as early as possible. One of the best in this respect is 'Outdoor Girl', which often matures a good fortnight before other varieties. It is a good cropper producing flavoursome, slightly ribbed fruits.

For growing in the greenhouse, 'Infinity Cross' is highly regarded, producing 1.8kg (4lb) from each of 4 or 5 trusses in an unheated greenhouse and 2.7-3.6kg (6-8lb) from as many as 8 trusses per plant in a heated greenhouse.

If space is limited then it is possible to grow tomatoes in a windowbox and, for this purpose, 'Tiny Tim' fits the bill. This is a dwarf bush variety producing scarlet cherry-like fruits which are almost seedless.

Other Tomato Varieties

Here are some odd varieties of tomato, which are grown in the United States, that you might want to try growing and eating instead of the standard genetically-enhanced Bushel Boy:

• Juliet, indeterminate: cherry tomato, but shaped like a Romano (elongated, not round) and very flavourful.

• Yellow Boy, indeterminate: shaped and sized like a small regular tomato, but bright yellow, more flavourful.

• Yellow Pear, some varieties are indeterminate, some determinate: cherry tomato-sized, pear shaped, quite zingy and sweet.

• Red Currant, determinate: marble-sized tart red tomatoes.

• Green Zebra, indeterminate: striped dark and yellowish-green, medium sized, firm and not too tart.

Using Tomatoes

Tomatoes are delicious eaten raw as you would an apple; or in, for example cheese and tomato or ham and tomato sandwiches, or in salads. Cheese and tomato also makes a delicious topping for baked potatoes. Tomatoes may also be used as an ingredient in cooked dishes, for example bolognese sauce. Recipes abound for cooked dishes and are not to be repeated here.

If perchance you have green tomatoes left at the end of the season, you can encourage them to ripen by placing them together with an apple or a banana in a bowl on a sunny windowsill. Apples and bananas give off ethene gas, a fruit-ripening hormone. An over-abundance of green tomatoes can be used to make green tomato chutney.

La Tomatina

La Tomatina is a week-long food fight festival, beginning on the last Wednesday of August each year in the town of Buñol in the Valencia region of Spain. This event is attended by tens of thousands of people from all over the world, during which some 90,000lb (over 40,000kg) of tomatoes are thrown at anything that moves.