Lactuca sativa crispa
| Lactuca sativa | |
| Light: |   |
| Moisture: |  |
| Hardiness: | 6 |
| Soil pH: | 6.6-8.4 |
| Self Pollinated | |
| Height: | 3' |
| Width: | 1' |
| Blooms: | Mid Summer-Late Summer |
| Edible Rating: |  |
| Medicinal Rating: |  |
| Tea: | Yes |
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Lactuca sativa crispa (common name: cutting lettuce)
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.
Cultivation: Prefers a light sandy loam[1]. Succeeds in most well-drained, humus-rich soils but dislikes acid conditions[1][2]. 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[3][4].
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. This is the curled or leaf lettuce. It does not form a central heart but produces a loose rosette of basal leaves and can be harvested on a cut and come again basis. There are many named varieties[5] capable of providing fresh leaves throughout the year if winter protection is given in temperate areas.
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[3][4][6]. They also grow well with cucumbers, cabbages and beetroot[6].
Range: Of garden origin, probably derived from L. serriola.
Habitat: Not known in the wild.
Edibility: Leaves - raw or cooked[7][8]. 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[5]. This variety forms a loose rosette of leaves and can be harvested on a cut and come again basis.
Seed - sprouted and used in salads or sandwiches[5].
An edible oil is obtained from the seed[7]. The seed is very small, extraction of the oil on any scale would not be very feasible[K].
Medicinal: 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[9]. The sap contains 'lactucarium', which is used in medicine for its anodyne, antispasmodic, digestive, diuretic, hypnotic, narcotic and sedative properties[10][11][12][13][14][15][16]. Lactucarium has the effects of a feeble opium, but without its tendency to cause digestive upsets[9], nor is it addictive[7]. It is taken internally in the treatment of insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, whooping cough, rheumatic pain etc[16]. Concentrations of lactucarium are low in young plants and most concentrated when the plant comes into flower[16]. 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[9]. The cultivated lettuce does not contain as much lactucarium as the wild species, most being produced when the plant is in flower[9]. An infusion of the fresh or dried flowering plant can also be used[10].
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[16] and overdoses can cause death through cardiac paralysis[7][10].
Some physicians believe that any effects of this medicine are caused by the mind of the patient rather than by the medicine[15].
The sap has also been applied externally in the treatment of warts[17].
The seed is anodyne and galactogogue[18].
Lettuce has acquired a folk reputation as an anaphrodisiac, anodyne, carminative, diuretic, emollient, febrifuge, hypoglycaemic, hypnotic, narcotic, parasiticide and sedative[18].
Usage: Parasiticide[19]. 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[18].
Pollinators: Flies, self
Soil: Can grow in light and medium soils.
Drainage: Prefers well drained soil.
Seed Ripens: Late Summer-Early Fall
Flower Type: Hermaphrodite
Known Hazards: The mature plant is mildly toxic[20].
Links
References
- ↑ 1.0 1.1 Chittendon, Fred. RHS Dictionary of Plants. Oxford University Press, 1951.
- ↑ Simons, Arthur. New Vegetable Growers Handbook. Penguin, 1977.
- ↑ 3.0 3.1 Philbrick, Helen and Richard Gregg. Companion Plants. Watkins, 1979.
- ↑ 4.0 4.1 Riotte, Louise. Carrots Love Tomatoes. Garden Way, 1978.
- ↑ 5.0 5.1 5.2 Facciola, Stephen. Cornucopia - A Source Book of Edible Plants. Kampong Publications, 1990.
- ↑ 6.0 6.1 Allardice, Pamela. A-Z of Companion Planting. Cassell Publishers, 1993.
- ↑ 7.0 7.1 7.2 7.3 Chiej, Roberto. Encyclopaedia of Medicinal Plants. MacDonald, 1984.
- ↑ Thompson, Robert. The Gardener's Assistant. Blackie and Son, 1878.
- ↑ 9.0 9.1 9.2 9.3 Grieve, Margaret. A Modern Herbal. Penguin, 1984.
- ↑ 10.0 10.1 10.2 Launert, Edmund. Edible and Medicinal Plants. Hamlyn, 1981.
- ↑ Lust, John. The Herb Book. Bantam Books, 1983.
- ↑ Uphof, Johannes. Dictionary of Economic Plants. Weinheim, 1959.
- ↑ Mills, Simon. The Dictionary of Modern Herbalism.
- ↑ Emboden, William. Narcotic Plants. Studio Vista, 1979.
- ↑ 15.0 15.1 Weiner, Michael. Earth Medicine, Earth Food. Ballantine Books, 1980.
- ↑ 16.0 16.1 16.2 16.3 Bown, Deni. Royal Horticultural Society Encyclopaedia of Herbs and Their Uses. Dorling Kindersley, 1995.
- ↑ Foster, Steven and Billy Tatum. Medicinal Plants of Eastern and Central North America. Houghton Mifflin, 1990.
- ↑ 18.0 18.1 18.2 Duke, James and Edward Ayensu. Medicinal Plants of China. Reference Publications, 1985.
- ↑ Stuart, George. Chinese Materia Medica. Taipei Southern Materials Centre.
- ↑ Triska, Jan. Encyclopaedia of Plants. Hamlyn, 1975.