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Solanum tuberosum - L.

Potato

Author	L.	Botanical references	200
Family	Solanaceae	Genus	Solanum
Synonyms
Known Hazards	All green parts of the plant, including the green parts of tubers, are poisonous, containing an alkaloid called 'solanine'.[7, 10, 19]. These solanines are also produced in potato shoots when they sprout, even if the potato is in the dark and the shoots are not green[65].
Range	Western S. America.
Habitat	Not known in a truly wild situation.
Edibility Rating	5 (1-5)	Medicinal Rating	2 (1-5)

Physical Characteristics

Perennial growing to 1m.

The plant prefers light (sandy), medium (loamy) and heavy (clay) soils and requires well-drained soil. The plant prefers acid and neutral soils. It cannot grow in the shade. It requires moist soil.

Habitats

Cultivated Beds;

Edible Uses

Edible Parts: Root.

Edible Uses: Rutin.

Root - raw or cooked. Potatoes are a very versatile food that can be used in a wide variety of ways. Having a mild flavour, and readily accepting the flavour of other foods, they can be eaten on a regular basis without becoming boring. Whilst occasionally eaten raw, they are most commonly cooked and can boiled, baked, fried, added to soups, stews etc[183]. The cooked potato can also be dried and made into a powder and then used as a thickener in soups etc, or be added to cereal flours when making bread, biscuits etc[4]. The potato is a very rich source of starch, but does not contain high quantities of other nutrients. When exposed to light, the skin turns green and contains the toxin solanine. Whilst eating a small quantity of green potato is unlikely to cause harm, it is probably wisest to remove any green part of the tuber before eating it. The fresh petals of white-flowered varieties contain 0.2% rutin[240].

Composition

Figures in grams (g) or miligrams (mg) per 100g of food.

Root (Fresh weight)

• 80 Calories per 100g
• Water: 79%
• Protein: 2.4g; Fat: 0.1g; Carbohydrate: 18g; Fibre: 0.5g; Ash: 1.3g;
• Minerals - Calcium: 10mg; Phosphorus: 51mg; Iron: 0.8mg; Magnesium: 0mg; Sodium: 5mg; Potassium: 401mg; Zinc: 0mg;
• Vitamins - A: 20mg; Thiamine (B1): 0.9mg; Riboflavin (B2): 0.03mg; Niacin: 1.5mg; B6: 0mg; C: 20mg;
• Reference: [269]
• Notes: These figures are the mean obtained from a range of readings.

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.

Antibacterial; Antifungal; Antiphlogistic; Antispasmodic; Cardiotonic; Hypotensive; Poultice.

Whilst mainly used as a staple food, potatoes do also have a number of medicinal virtues. A juice made from the tubers, when taken in moderation, can be helpful in the treatment of peptic ulcers, bringing relief from pain and acidity[254]. Excessive doses of potato juice can be toxic - do not drink the juice of more than one large potato per day[254]. A poultice has been made from boiling potatoes in water[4]. This is applied as hot as can be borne to rheumatic joints, swellings, skin rashes, haemorrhoids etc[4, 254]. Peeled but uncooked potatoes have been pounded in a mortar and then applied cold as a soothing plaster to burns and scalds[4]. Potato skins are used in India to treat swollen gums and to heal burns[254]. The tubers contain very small quantities of atropine alkaloids. One property of these alkaloids is the reduction of digestive secretions, including acids produced in the stomach[254]. The root and leaf diffusates of growing potato plants possess cardiotonic activity[269]. Dried ethanol extracts of above-ground parts of the plant show marked hypotensive and myotropic action and a spasmolytic and soothing effect on intestinal musculature[269]. Ethanol extracts of the leaves have antifungal properties, active against Phytophthora infestans[269]. The leaves, seeds, and tuber extracts show antimicrobial activity against Gram-positive and Gram-negative bacteria[269]. The leaves are antispasmodic[7, 201].

Other Uses

Alcohol; Biomass; Cleanser; Cosmetic; Polish; Size; Starch.

The tubers are a source of starch that is used in sizing cotton and to make industrial alcohol etc[100, 142]. It also has many other uses in industry[171]. Ripe potato juice is an excellent cleaner of silks, cottons and woollens[4]. The water in which potatoes have been boiled can be used to clean silver and to restore a shine to furniture[7]. Emollient and cleansing face masks are made from potatoes, these are used to treat hard, greasy and wrinkled skins[7]. The potato is a good source of biomass. When boiled with weak sulphuric acid, potato starch is changed into glucose and this can then be fermented into alcohol[4].

Cultivation details

Succeeds in most soils, preferably in a sunny position[1]. It performs well on a wide variety of soils, sandy loams, silt loams, loams, and peats[269]. Dislikes wet or heavy clay soils[16, 37]. Prefers a slightly acid soil, the tubers are subject to scab on limy soils or those deficient in humus. Yields are best from plants grown in rich soils with plenty of organic matter. The plant is reported to tolerate an annual precipitation in the range of 9 to 410cm, an annual temperature in the range of 3.6 to 27.8°C and a pH of 4.2 to 8.2[269]. Potatoes are a cool weather crop, the optimal temperature for growth being 15 - 20°C for most cvs. Growth of the tubers is best at soil temperature of 17 - 20°C, with usually no tubers formed above 32°C. The top-growth of this species is not frost hardy, though the tubers will tolerate a few degrees of frost if left in the ground[200]. Potatoes are very widely grown throughout the world for their edible tubers, there are many named varieties[132]. The potato is one of the main staple foods, it is very high yielding (50 tonnes or more per hectare have been achieved in some European countries, though at the other extreme yields of little more than 2 tonnes have been achieved in parts of Africa), stores well and can be available all year round. The potato probably arose through cultivation from several wild species that can still be found growing in S. America. Many of these wild species can be used in breeding programmes for improved disease resistance etc. Does well when grown after a crop of rye, Secale cereale[18, 20]. Grows well with legumes, sweet corn, cabbage, marigolds, horse radish, flax, dead nettles, sainfoin and nasturtiums[18, 20]. Grows badly with tomatoes, sunflowers, members of the cucumber family and raspberries[18, 20]. Potatoes should not be stored with apples because the ethylene gas released by the apples will cause the potatoes to go soft and develop a sour taste[201].

Propagation

Seed - sow early spring in a greenhouse. When they are large enough to handle, prick the seedlings out into individual pots and plant them out into their permanent positions after the last expected frosts. If grown on fast it is possible to get a reasonable crop in the first year though the normal way of growing potatoes is from tubers. Seed from named varieties will not breed true to type but will usually give a good crop. Division of tubers. Harvest in the autumn, store in a cool frost free place overwinter. Chit the potatoes to encourage the growth of sprouts in the new year and plant out in spring.

Cultivars

There are many named varieties of this annual vegetable, with new forms being developed each year. At present there is not time to enter these in the database and it is recommended that you consult the book 'The Fruit and Vegetable Finder' which is updated regularly and can be obtained from libraries.

Links

References

[1] F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaces in 1992 by a new dictionary (see [200]).

[4] Grieve. A Modern Herbal. Penguin 1984 ISBN 0-14-046-440-9
Not so modern (1930's?) but lots of information, mainly temperate plants.

[7] Chiej. R. Encyclopaedia of Medicinal Plants. MacDonald 1984 ISBN 0-356-10541-5
Covers plants growing in Europe. Also gives other interesting information on the plants. Good photographs.

[10] Altmann. H. Poisonous Plants and Animals. Chatto and Windus 1980 ISBN 0-7011-2526-8
A small book, reasonable but not very detailed.

[16] Simons. New Vegetable Growers Handbook. Penguin 1977 ISBN 0-14-046-050-0
A good guide to growing vegetables in temperate areas, not entirely organic.

[18] Philbrick H. and Gregg R. B. Companion Plants. Watkins 1979
Details of beneficial and antagonistic relationships between neighbouring plants.

[19] Stary. F. Poisonous Plants. Hamlyn 1983 ISBN 0-600-35666-3
Not very comprehensive, but easy reading.

[20] Riotte. L. Companion Planting for Successful Gardening. Garden Way, Vermont, USA. 1978 ISBN 0-88266-064-0
Fairly good.

[37] Thompson. B. The Gardener's Assistant. Blackie and Son. 1878
Excellent general but extensive guide to gardening practices in the 19th century. A very good section on fruits and vegetables with many little known species.

[65] Frohne. D. and Pfänder. J. A Colour Atlas of Poisonous Plants. Wolfe 1984 ISBN 0723408394
Brilliant. Goes into technical details but in a very readable way. The best work on the subject that I've come across so far.

[100] Polunin. O. Flowers of Europe - A Field Guide. Oxford University Press 1969 ISBN 0192176218
An excellent and well illustrated pocket guide for those with very large pockets. Also gives some details on plant uses.

[132] Bianchini. F., Corbetta. F. and Pistoia. M. Fruits of the Earth. 0
Lovely pictures, a very readable book.

[142] Brouk. B. Plants Consumed by Man. Academic Press 1975 ISBN 0-12-136450-x
Readable but not very comprehensive.

[171] Hill. A. F. Economic Botany. The Maple Press 1952
Not very comprehensive, but it is quite readable and goes into some a bit of detail about the plants it does cover.

[183] Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990 ISBN 0-9628087-0-9
Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992 ISBN 0-333-47494-5
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.

[201] Allardice.P. A - Z of Companion Planting. Cassell Publishers Ltd. 1993 ISBN 0-304-34324-2
A well produced and very readable book.

[240] Chopra. R. N., Nayar. S. L. and Chopra. I. C. Glossary of Indian Medicinal Plants (Including the Supplement). Council of Scientific and Industrial Research, New Delhi. 1986
Very terse details of medicinal uses of plants with a wide range of references and details of research into the plants chemistry. Not for the casual reader.

[254] Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London 1996 ISBN 9-780751-303148
An excellent guide to over 500 of the more well known medicinal herbs from around the world.

[269] Duke. J. Handbook of Energy Crops - 1983
Published only on the Internet, excellent information on a wide range of plants.

Readers Comments

Plants for a Future does not verify the accuracy of reader comments, use at your own risk. In particular Plants For A Future can not take any responsibility for any adverse effects from the use of plants. You should always consult a professional before using plants medicinally.

Solanum tuberosum

Wed Apr 27 10:21:29 2005

Can you tell me if using potato juice drops in the eyes is safe? I was told my son would need atropine drops in his eye for regular treatment for a lazy eye, but I'm worried about it. I would rather a natural solution. I heard that the same ingredient is contain in the potato and tomatoes - are they safe to put in the eye or could they cause blindness?

Solanum tuberosum

cham Wed Jul 12 2006

hmmm.this could probably be a big help for the preparation of my investigatory project,because i have read that there are still so many uses of potato aside from an engridient to our food..

Solanum tuberosum

archit m. patel Sun Oct 8 2006

This starch is distributed in all the plants.this page is very interesting.

Solanum tuberosum

Luisa Tue Oct 10 2006

How many percent of Alkaloid can be found in Potatoes? What possible tests can be made to pro ove that it is present in Alkaloid

Solanum tuberosum

prynne Sat Jan 13 2007

is a potato extract can be processed into ethanol? what is the process?? can you tell me??

Solanum tuberosum

Potato Tue Apr 15 2008

Can anybody explain the entire process of producing wood alcohol from potatos?

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