Common Name: Tomato

General Information

Solanum lycopersicum, the cultivated tomato, is an erect or spreading annual plant varying in size from 30cm to 2 metres or more.
A very well known fruit, tomatoes are widely grown throughout the world. In addition to their edible fruits, they also provide an oil, can be used as insect repellents and have a range of traditional medicinal uses.

Known Hazards

All green parts of the plant are poisonous[, ].
Although providing many well-known foods for people, including the potato, tomato, pepper and aubergine, most species in this genus also contain toxic alkaloids. Whilst these alkaloids can make the plant useful in treaing a range of medical conditions, they can also cause problems such as nausea, vomiting, salivation, drowsiness, abdominal pain, diarrhoea, weakness and respiratory depression[].
Unless there are specific entries with information on edible uses, it would be unwise to ingest any part of this plant[].

Botanical References

Range

Original habitat is obscure, probably Western S. America[].

Habitat

Not known in a truly wild situation.

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual
Height	2.00 m
Pollinators	Insects, Self
Self-fertile	Yes
Cultivation Status	Cultivated

Cultivation Details

A plant of the tropics, it is also widely cultivated in the subtropics and temperate zone (where it is often grown under protection). In the tropics it can be grown at elevations from sea level up to 2,000 metres, but generally fruits better above 1,000 metres[]. It grows best in areas where annual daytime temperatures are within the range 20 - 27°c, but can tolerate 7 - 35°c[]. It prefers a diurnal temperature variation of at least 5 - 6°c[]. It prefers a mean annual rainfall in the range 600 - 1,300mm, but tolerates 400 - 1,800mm[]. High rainfall and high relative humidity adversely affect growth[]. Tomato plants are not frost-tolerant and in the temperate zone generally need to be started off in a greenhouse in the spring if they are to succeed outdoors. They also need a hot sunny summer if they are to fruit well.
Requires a fertile, humus-rich, well-drained soil in a warm sunny position[]. Slightly acid conditions, with a pH in the range 5.8 - 6.8, are preferred, though the plant can tolerate 5 - 7.5[, ].
Harvesting of ripe fruit from upright forms of the plant can commence 2 - 3 months after sowing the seed; other forms might take 4 - 5 months[, ].
Yields of 15 tonnes per hectare can be obtained[]. Yields are mainly between 20 - 40 tonnes per hectare, but yields up to 150 tonnes have been recorded[].
Some varieties have been developed that can be successfully grown outdoors during the summer in temperate climates such as Britain, although good summers are still required in order to get reasonable yields. Varieties have been developed in Eastern Europe that can flower and set fruit at 7°c (this is compared with a temperature requirement of 11 - 13°c in earlier
There are many named varieties and over the considerable period of cultivation by humans two distinct types have emerged[]. These are:-
Solanum lycopersicum cerasiforme (Dunal.)A.Gray. This is the cherry tomato. Closer to the original species, it produces a large crop of small fruits with a delicious sweetness.
Solanum lycopersicum esculentum. This is the more commonly grown tomato with much larger fruits. There are a very large number of cultivars with a wide variety of colours and fruit shapes and sizes.
This species hybridizes with the currant tomato (Solanum pimpinellifolium), but does not hybridize with the wild tomato (Solanum peruvianum)[].

Edible Uses

Fruit - raw or cooked[, , , ]. It can be used as a savoury vegetable or flavouring in cooked foods, or can be eaten out of hand as a dessert fruit. It is much used in salads and as a flavouring in soups and other cooked foods[]. A juice made from the fruit is often sold in health food shops[]. The fruit can also be dried and ground into a powder that can be used as a flavouring and thickening agent in soups, breads, pancakes etc[].

An edible oil is obtained from the seed[, , ]. Suitable for culinary purposes[]. It can be used raw in salads, or used to make margarine[]. The seed is small and it would be very fiddly to utilize. It is only viable to use the seed as a source of oil if large quantities of the plants are being grown for their fruits and the seed is not wanted.

Medicinal

The pulped fruit is an extremely beneficial skin-wash for people with oily skin. Sliced fruits are a quick and easy first aid treatment for burns, scalds and sunburn[].

A decoction of the root is ingested in the treatment of toothache[].

The skin of tomato fruits is a good source of lycopine, a substance that has been shown to protect people from heart attacks. It seems to be more effective when it is cooked and so can be obtained from food products such as tomato ketchup and tinned tomatoes[]. Lycopine has also been shown to have a very beneficial effect upon the prostate and is being used increasingly to treat enlarge prostate and the difficulties in urination that accompany this disorder.

The leaves, in a mixture with castor oil (Ricinus communis), is used in the treatment of incipient leprosy spots[]. A paste of the leaves is applied to filarial worm swellings on a painful groin[].

A homeopathic remedy is made from the plant[]. It is used in the treatment of rheumatism and severe headaches[].

Agroforestry Uses:

Tomatoes grow well with asparagus, parsley, brassicas and stinging nettles[, ]. They are also a good companion for gooseberries, helping to keep them free of insect pests[]. They dislike growing near fennel, kohl-rabi, potatoes[, ] and brassicas[] (this is not a typing error, merely a difference of opinion between different books).

Other Uses

The strong aroma of this plant is said to repel insects from nearby plants[, , ].

A semi-drying oil is obtained from the seed. It can be used in making soap[, , ]. See the notes above regarding utilization.

A spray made from tomato leaves is an effective but very poisonous insecticide[]. It is especially effective against ants[] but should be used with great caution because it will also kill beneficial insects and, if ingested, is toxic to humans[].

The pulp of the fruit is used cosmetically in face-packs[].
Various parts of the plant are used as ingredients in commercial cosmetic preparations. The fruit and its extracts are used as antioxidants, emollients, humectanst and skin conditioners[]. An extract from the fruit, leaves and stems is used as an astringent and skin conditioner[]. The seed oil is used as an emollient and skin conditioner[].

Propagation

Seed - sow early spring in a warm greenhouse. Germination is usually quick and good. Pot up the seedlings into individual pots of fairly rich compost as soon as the first true leaf appears and plant them out after the last expected frosts.
Seed can also be sown in situ under a cloche at the end of mid spring, though in a cool summer the results may be disappointing.
The seedcoat may carry tomato mosaic virus. However, by sowing the seed 15mm deep the seedcoat will remain below the soil surface when the seed germinates and the disease will be inactivated[].