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Uses

Toxic parts

The mature plant is mildly toxic[1].

Edible uses

Notes

Leaves - raw or cooked[2][3]. A mild slightly sweet flavour with a crisp texture, lettuce is a very commonly used salad leaf and can also be cooked as a potherb or be added to soups etc[4]. A nutritional analysis is available[5].

Seed - sprouted and used in salads or sandwiches[4].

An edible oil is obtained from the seed[2]. The seed is very small, extraction of the oil on any scale would not be very feasible[K].

Leaves

Unknown part

Oil

Material uses

Parasiticide[6]. No further details are given, but it is probably the sap of flowering plants that is used. The seed is said to be used to make hair grow on scar tissue[5].

Unknown part

Medicinal uses(Warning!)

The whole plant is rich in a milky sap that flows freely from any wounds. This hardens and dries when in contact with the air[7]. The sap contains 'lactucarium', which is used in medicine for its anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic and sedative properties[8][9][10][11][12][13][14]. Lactucarium has the effects of a feeble opium, but without its tendency to cause digestive upsets[7], nor is it addictive[2]. It is taken internally in the treatment of insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, whooping cough, rheumatic pain etc[14]. Concentrations of lactucarium are low in young plants and most concentrated when the plant comes into flower[14]. It is collected commercially by cutting the heads of the plants and scraping the juice into china vessels several times a day until the plant is exhausted[7]. The cultivated lettuce does not contain as much lactucarium as the wild species, most being produced when the plant is in flower[7]. An infusion of the fresh or dried flowering plant can also be used[8].

The plant should be used with caution, and never without the supervision of a skilled practitioner. Even normal doses can cause drowsiness whilst excess causes restlessness[14] and overdoses can cause death through cardiac paralysis[2][8]. Some physicians believe that any effects of this medicine are caused by the mind of the patient rather than by the medicine[13]. The sap has also been applied externally in the treatment of warts[15]. The seed is anodyne and galactogogue[5].

Lettuce has acquired a folk reputation as an anaphrodisiac, anodyne, carminative, diuretic, emollient, febrifuge, hypoglycaemic, hypnotic, narcotic, parasiticide and sedative[5].

Ecology

Ecosystem niche/layer

Ecological Functions

Nothing listed.

Forage

Nothing listed.

Shelter

Nothing listed.

Propagation

Seed - sow a small quantity of seed in situ every 2 or 3 weeks from March (with protection in cooler areas) to June and make another sowing in August/September for a winter/spring crop. Only just cover the seed. Germination is usually rapid and good, thin the plants if necessary, these thinnings can be transplanted to produce a slightly later crop (but they will need to be well watered in dry weather). More certain winter crops can be obtained by sowing in a frame in September/October and again in January/February.

Practical Plants is currently lacking information on propagation instructions of Lactuca sativa. Help us fill in the blanks! Edit this page to add your knowledge.



Cultivation

Prefers a light sandy loam[16]. Succeeds in most well-drained, humus-rich soils but dislikes acid conditions[16][17]. Plants strongly dislike dry conditions, quickly running to seed in such a situation. Early and late sowings are best in a sunny position, but summer crops are best given a position with some shade in order to slow down the plants tendency to go to seed and to prevent the leaves becoming bitter[18][19].

The garden lettuce is widely cultivated in many parts of the world for its edible leaves and is probably the most commonly grown salad plant. There are many named varieties[4] capable of providing fresh leaves throughout the year if winter protection is given in temperate areas. Over the centuries a number of more or less distinct forms have arisen in cultivation. These forms have been classified as follows. They are treated separately in more detail:-

    L. sativa angustana. L.H.Bailey. is the Celtuce. The leaves of this form are not of such good quality as the other lettuces and the plant is grown more for its thick central stem which is used in the same ways as celery[16].
    L. sativa capitata. L. is the heading lettuce, it forms a heart in a similar way to cabbages. Examples of this include the Iceberg and Butterhead lettuces.
    L. sativa crispa. L. is the curled or leaf lettuce. This does not form a central heart but produces a loose rosette of basal leaves. It can be harvested on a cut and come again basis.
    L. sativa longifolia Lam. is the cos lettuce. This has longer, thinner leaves and a more erect habit, it does not form a compact heart.

Lettuces are quite a problematic crop to grow. They require quite a lot of attention to protect them from pests such as slugs, aphids and birds. If the weather is hot and dry the plants tend to run very quickly to seed, developing a bitter flavour as they do so. In wet weather they are likely to develop fungal diseases. In addition, the seed needs to be sown at regular intervals of 2- 3 weeks during the growing season in order to provide a regular supply of leaves.

Lettuces make a good companion plant for strawberries, carrots, radishes and onions[18][19][20]. They also grow well with cucumbers, cabbages and beetroot[20].

Crops

Problems, pests & diseases

Associations & Interactions

There are no interactions listed for Lactuca sativa. Do you know of an interaction that should be listed here? edit this page to add it.

Polycultures & Guilds

There are no polycultures listed which include Lactuca sativa.

Descendants

Cultivars

Varieties

None listed.

Subspecies

None listed.

Full Data

This table shows all the data stored for this plant.

Taxonomy
Binomial name
Lactuca sativa
Genus
Lactuca
Family
Compositae
Imported References
Material uses & Functions
Botanic
Propagation
Cultivation
Environment
Cultivation
Uses
Edible uses
None listed.
Material uses
None listed.
Medicinal uses
None listed.
Functions & Nature
Functions
Provides forage for
Provides shelter for
Environment
Hardiness Zone
6
Heat Zone
?
Water
moderate
Sun
full sun
Shade
light shade
Soil PH
Soil Texture
Soil Water Retention
Environmental Tolerances
    Ecosystems
    Native Climate Zones
    None listed.
    Adapted Climate Zones
    None listed.
    Native Geographical Range
    None listed.
    Native Environment
    None listed.
    Ecosystem Niche
    None listed.
    Root Zone Tendancy
    None listed.
    Life
    Deciduous or Evergreen
    ?
    Herbaceous or Woody
    ?
    Life Cycle
    Growth Rate
    ?
    Mature Size
    Fertility
    Pollinators
    Flower Colour
    ?
    Flower Type

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    References

    1. ? Triska. Dr. Hamlyn Encyclopaedia of Plants. Hamlyn ISBN 0-600-33545-3 (1975-00-00)
    2. ? 2.02.12.22.32.42.5 Chiej. R. Encyclopaedia of Medicinal Plants. MacDonald ISBN 0-356-10541-5 (1984-00-00)
    3. ? 3.03.1 Thompson. B. The Gardener's Assistant. Blackie and Son. (1878-00-00)
    4. ? 4.04.14.24.3 Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications ISBN 0-9628087-0-9 (1990-00-00)
    5. ? 5.05.15.25.35.45.55.6 Duke. J. A. and Ayensu. E. S. Medicinal Plants of China Reference Publications, Inc. ISBN 0-917256-20-4 (1985-00-00)
    6. ? 6.06.1 Stuart. Rev. G. A. Chinese Materia Medica. Taipei. Southern Materials Centre ()
    7. ? 7.07.17.27.37.4 Grieve. A Modern Herbal. Penguin ISBN 0-14-046-440-9 (1984-00-00)
    8. ? 8.08.18.28.3 Launert. E. Edible and Medicinal Plants. Hamlyn ISBN 0-600-37216-2 (1981-00-00)
    9. ? 9.09.1 Lust. J. The Herb Book. Bantam books ISBN 0-553-23827-2 (1983-00-00)
    10. ? 10.010.1 Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim (1959-00-00)
    11. ? 11.011.1 Mills. S. Y. The Dictionary of Modern Herbalism. ()
    12. ? 12.012.1 Emboden. W. Narcotic Plants Studio Vista ISBN 0-289-70864-8 (1979-00-00)
    13. ? 13.013.113.2 Weiner. M. A. Earth Medicine, Earth Food. Ballantine Books ISBN 0-449-90589-6 (1980-00-00)
    14. ? 14.014.114.214.314.4 Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. ISBN 0-7513-020-31 (1995-00-00)
    15. ? 15.015.1 Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. ISBN 0395467225 (1990-00-00)
    16. ? 16.016.116.2 F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press (1951-00-00)
    17. ? Simons. New Vegetable Growers Handbook. Penguin ISBN 0-14-046-050-0 (1977-00-00)
    18. ? 18.018.1 Philbrick H. and Gregg R. B. Companion Plants. Watkins (1979-00-00)
    19. ? 19.019.1 Riotte. L. Companion Planting for Successful Gardening. Garden Way, Vermont, USA. ISBN 0-88266-064-0 (1978-00-00)
    20. ? 20.020.1 Allardice.P. A - Z of Companion Planting. Cassell Publishers Ltd. ISBN 0-304-34324-2 (1993-00-00)
    21. ? Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press ISBN 0-333-47494-5 (1992-00-00)

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