Common Name: Alfalfa

General Information

Medicago sativa is a herbaceous perennial plant with erect to ascending, rarely prostrate, much-branched stems growing from a deep taproot; it can grow from 30 - 100cm tall[].
The plant is harvested from the wild for use as a food and medicine. Alfalfa has long been cultivated for its wide range of uses, including its edible seed, which can be sprouted and eaten in salads. It is also commonly grown as a green manure and soil restorer.
The wild subspecies of Medicago sativa are widespread across Eurasia, with no major threats and stable populations. They are also well conserved in ex situ gene bank collections. The plant is classified as 'Least Concern' in the IUCN Red List of Threatened Species(2013)[].

Known Hazards

The plant contains saponin-like substances[]. Eating large quantities of the leaves may cause the breakdown of red blood cells[].
Although poisonous, saponins also have a range of medicinal applications and many saponin-rich plants are used in herbalism (particularly as emetics, expectorants and febrifuges) or as sources of raw materials for the pharmaceutical industry. Saponins are also found in a number of common foods, such as many beans.
Saponins have a quite bitter flavour and are in general poorly absorbed by the human body, so most pass through without harm. They can be removed by carefully leaching in running water. Thorough cooking, and perhaps changing the cooking water once, will also normally remove most of them. However, it is not advisable to eat large quantities of raw foods that contain saponins.
Saponins are much more toxic to many cold-blooded creatures, such as fish, and hunting tribes have traditionally put large quantities of them in streams, lakes etc in order to stupefy or kill the fish and make them easy to catch[].
Alfalfa sprouts (and especially the seeds) contain canavanine. Recent reports suggest that ingestion of this substance can cause the recurrence of systemic lupus erythematosus (an ulcerous disease of the skin) in patients where the disease had become dormant[].

Botanical References

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Range

Widely distributed (often naturalized) in Eurasia from Norway to Portugal, east to eastern Siberia, Mongolia, central Asia, and Pakistan; N. Africa

Habitat

Waste ground, avoiding acid soils[].

Properties

Conservation Status	Least Concern
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	0.80 m
Growth Rate	Medium
Pollinators	Bees, Lepidoptera, Self
Self-fertile	Yes
Cultivation Status	Cultivated, Wild

Cultivation Details

Medicago sativa is a plant of the temperate to subtropical zones of Europe, Asia and N. Africa, where it is found at elevations up to 4,000 metres. It grows best in areas where annual daytime temperatures are within the range 21 - 27°c, but can tolerate 5 - 45°c[]. When dormant, the plant can survive temperatures down to about -25°c, but young growth is more tender and can be severely damaged at 0°c[]. It prefers a mean annual rainfall in the range 600 - 1,200mm, but tolerates 350 - 2,700mm[].
Grows best in a sunny position, but tolerates light shade[]. The plant succeeds on a wide variety of soils[, ], but thrives best on a rich, friable, well-drained loamy soil with loose topsoil supplied with lime[]. It does not tolerate waterlogging and fails to grow on very acid soils[]. Grows well on light soils[]. The plant has a deep taproot and, once establishd, tolerates drought and extremely dry conditions, though it will become dormant in severe drought[, , ]. Prefers a neutral fertile soil[] but succeeds in relatively poor soils so long as the appropriate Rhizobium bacteria is present[]. Prefers a pH in the range 6.5 - 7.5, tolerating 4.3 - 8.7[].
Alfalfa has long been cultivated for its edible seed, which can be sprouted and eaten in salads. It is also grown as a green manure and soil restorer.
Seed yields can range from 50 - 750 kilos per hectare[], with an average range around 186 - 280 kilos[].
There are many named varieties[].
Botanists divide the species into a number of sub-species - these are briefly described below:-
M. sativa caerulea (Less. ex Ledeb.)Schmalh. This sub-species is likely to be of value in breeding programmes for giving cold tolerance, drought resistance and salt tolerance to alfalfa.
M. sativa falcata (L.)Arcang. This sub-species is likely to be of value in breeding programmes for giving cold tolerance, drought and disease resistance plus salt and water-logging tolerance to alfalfa.
M. sativa sativa. The commonly cultivated form of alfalfa.
M. sativa varia (Martyn.)Arcang. This sub-species is likely to be of value in breeding programmes for giving cold tolerance, drought resistance and high yields to alfalfa.
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

Leaves and young shoots - raw or cooked[, , , ]. The leaves can also be dried for later use[]. Very rich in vitamins[], especially A, B and C[], they are also a good source of protein[]. The leaves are a rich source of vitamin K[]. Alfalfa is an important source of leaf meal used for fortifying baby food and other special diet foods prepared for human use[]. A very nutritious food in moderation, though it can trigger attacks in patients with systemic lupus erythematosus and large quantities can affect liver function and cause photosensitization[]. A nutritional analysis is available[].

The seed is commonly used as a sprouted seed which is added to salads[, , ], used in sandwiches etc or cooked in soups[]. The seed is soaked in warm water for 12 hours, then kept moist in a container in a warm place to sprout. It is ready in about 4 - 6 days[]. The seeds can also be ground into a powder and used as a mush, or mixed with cereal flours for making a nutritionally improved bread etc[, , ]. The seeds are rather small, about 1 - 2mm in diameter, with 10 - 20 seeds contained in a tightly coiled seedpod consisting of 2 - 6 coils spiralled in a 5 - 9mm[].

An appetite-stimulating tea is made from the leaves[, ], it has a flavour somewhat reminiscent of boiled socks[] and is slightly laxative[].

Medicinal

Alfalfa leaves, either fresh or dried, have traditionally been used as a nutritive tonic to stimulate the appetite and promote weight gain[]. The plant has an oestrogenic action and could prove useful in treating problems related to menstruation and the menopause[]. Some caution is advised in the use of this plant, however. It should not be prescribed to people with auto-immune diseases such as rheumatoid arthritis[]. See also the notes above on toxicity.

The plant is antiscorbutic, aperient, diuretic, oxytocic, haemostatic, nutritive, stimulant and tonic[, , ]. The expressed juice is emetic and is also anodyne in the treatment of gravel[]. The plant is taken internally for debility in convalescence or anaemia, haemorrhage, menopausal complaints, pre-menstrual tension, fibroids etc[].
A poultice of the heated leaves has been applied to the ear in the treatment of earache[]. The leaves can be used fresh or dried[].

The leaves are rich in vitamin K which is used medicinally to encourage the clotting of blood[]. This is valuable in the treatment of jaundice[].
The plant is grown commercially as a source of chlorophyll and carotene, both of which have proven health benefits[]. The leaves also contain the anti-oxidant tricin[].

The root is febrifuge and is also prescribed in cases of highly coloured urine[].

Extracts of the plant are antibacterial[].

Agroforestry Uses:

Often grown as a green manure, Medicago sativa is a bit slow to establish in its first year so is generally only recommended for positions where it can remain for 2 or more years. The plant is very vigorous from its second year, producing a huge bulk of material that can be cut down 2 or 3 times during the growing season[, ].
Plants are very deep rooting, descending 6 metres or more into the soil[], and are able to fix large quantities of atmospheric nitrogen, this makes them one of the very best green manures. Plants are rather intolerant of competition from grass etc, however, and there is the drawback of needing to leave them in the soil for more than 2 years to fully achieve their potential[].
Alfalfa is a potenially excellent source of biomass. It is possible to produce more than 2 tonnes of protein from the leaves (suitable for human use) per hectare per year. In addition, the plant residues remaining could be used to produce the equivalent of about 10 barrels of oil per year[].
The plants extensive root system makes it useful as a soil stabilizer[].
The plant can be grown as a low dividing hedge in the vegetable garden[, ].
A good source of nectar for bees[, ] and a food plant for many caterpillars[].
Alfalfa is a very deep rooting plant, bringing up nutrients from deep in the soil and making them available for other plants with shallower root systems. It is a good companion plant for growing near fruit trees and grape vines so long as it is in a reasonably sunny position, but it does not grow well with onions or other members of the Allium genus[]. Growing alfalfa encourages the growth of dandelions[].

Other Uses

A yellow dye is obtained from the seed[].

The fibre of the plant has been used in making paper[].

The seed yields about 8.5 - 11% of a drying oil. It is used in paints, varnish etc[, , , ].

An extract of the plant is used as an ingredient in commercial cosmetic preparations as a tonic[].
The juice extracted the flowers, leaves and young stems is used as an ingredient in commercial cosmetic preparations as an antioxidant[].
An extract of the leaves is used as an ingredient in commercial cosmetic preparations as a skin conditioner[].
An extract of the seeds , and also the seedpowder, are used as ingredients in commercial cosmetic preparations as a skin conditioner[].

Propagation

Pre-soak the seed for 12 hours in warm water and then sow in spring in situ. The seed can also be sown in situ in autumn[]. Seed can be obtained that has been inoculated with Rhizobium bacteria, enabling the plant to succeed in soils where the bacteria is not already present.