Common Name: French Bean

General Information

Phaseolus vulgaris is a herbaceous perennial climbing plant (though often annual in the wild and nearly always annual in cultivation), growing from a fibrous rootstock. The stem is strongly twining, 1 - 6 metres long, usually annual but sometimes surviving for two years in tropical climates. Non-climbing dwarf varieties have been developed in cultivation[].
The plant is commonly cultivated for its edible mature seeds and immature seedpods[].

Known Hazards

Large quantities of the raw mature seed are poisonous[, ]. Children eating just a few seeds have shown mild forms of poisoning with nausea and diarrhoea, though complete recovery took place in 12 - 24 hours[]. The toxins play a role in protecting the plant from insect predation[].

Botanical References

,

Range

The original habitat is obscure, but the plant has been found in a possibly wild form from Argentina through western S. America, C. America to Mexico

Habitat

Usually in drier localities of desert to thorny shrub, hillsides or steep slopes ín open pine-oak forests, growing in and over shrubs and brush.often at edges of thickets, trails, and over stone walls; at elevations from 800 - 2,000 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	2.00 m
Pollinators	Bees
Self-fertile	Yes
Cultivation Status	Cultivated

Cultivation Details

Phaseolus vulgaris is native to the tropics of the Americas, where it is usually found at elevations above 600 metres, though good crops can be obtained down to sea level[]. It can also be grown as a summer crop in regions of the temperate zone with a growing season of three months or more. A temperature in the range 19 - 27°c is preferred - above 30°c many flowers will abort and above 35°c seed is rarely produced[]. Climbing forms of the plant can succeed in areas of high rainfall, but dwarf forms appear to be more sensitive to high soil moisture levels[]. Heavy rain adversely affects fertilization[]. Plants require a dry season in order to mature the seed[].
Requires a warm sunny position in a rich well-drained preferably light soil with plenty of moisture in the growing season[, , ]. Dislikes heavy, wet or acid soils[, ]. Grows well in moderately heavy loam soils so long as they are well drained[].Prefers a pH in the range 5.5 to 6.5[].
There are many named forms, and these have been adapted for growing in the temperate, subtropical and tropical zones as well as in montane valleys of the tropics[]. The plant is often grown to provide a major part of the protein requirement[, ]. Immature pods of the dwarf forms can be harvested in about 40 - 60 days from sowing (70 - 90 days for climbing forms) whilst total yields of pods can reach 3 - 5 tonnes per hectare from the dwarf forms (4 - 6 tonnes from the climbing forms)[].
A very variable plant, there are more than 1,000 named varieties ranging from dwarf forms about 30cm tall to climbing forms up to 3 metres tall[, , , ]. The dwarf forms are daylength neutral and early maturing[]. Climbing forms, which can be either daylength neutral or short daylength types, take longer to mature a crop[].
When grown for their edible pods, the immature pods should be harvested regularly in order to promote extra flower production and therefore higher yields[]. Yields of green pods averages about 3kg per square metre, though double this can be achieved[].
French beans grow well with strawberries, carrots, cauliflowers, cucumbers, cabbage, beet, leek and celeriac[, ]. They are inhibited by alliums and fennel growing nearby[, ].
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[]. When removing plant remains at the end of the growing season, it is best to only remove the aerial parts of the plant, leaving the roots in the ground to decay and release their nitrogen.

Edible Uses

Immature seedpods - raw or cooked[, ]. The green pods are commonly used as a vegetable, they have a mild flavour and should only be cooked for a short time. The pods are up to 20cm long and 15mm wide[]. When growing the plant for its seedpods, be sure to pick them whilst they are still small and tender. This will ensure the continued production of more pods by the plant. Flowering is reduced once the seeds begin to form inside the pods.

The immature seeds are boiled or steamed and used as a vegetable[].

The mature seeds are dried and stored for future use. They must be thoroughly cooked before being eaten and are best soaked in water for about 12 hours prior to this. They can be boiled, baked, pureed, ground into a powder or fermented into 'tempeh' etc[]. The powdered seed makes a protein-enriching additive to flour, it can also be used in soups etc[]. The seed can also be sprouted and used in salads or cooked[]. The seed can be 7 - 16mm long[].

The roasted seeds have been used as a coffee substitute[].

Young leaves - raw or cooked as a potherb[, ]. The very young leaves are sometimes eaten as a salad, the older leaves are cooked[].

Medicinal

The green pods are mildly diuretic and contain a substance that reduces the blood sugar level[]. The dried mature pod is used according to another report[]. It is used in the treatment of diabetes[].

The seed is diuretic, hypoglycaemic and hypotensive[]. Ground into a flour, it is used externally in the treatment of ulcers[]. The seed is also used in the treatment of cancer of the blood[]. When bruised and boiled with garlic they have cured intractable coughs[].

The root is dangerously narcotic[].

A homeopathic remedy is made from the entire fresh herb[]. It is used in the treatment of rheumatism and arthritis, plus disorders of the urinary tract[].
A remedy made from the shells is used to treat diabetes[].

Other Uses

A brown dye is obtained from red kidney beans[].

The plant contains phaseolin, which has fungicidal activity[].

Water from the cooked beans is very effective in reviving woollen fabrics[].

The plant residue remaining after harvesting the dried beans is a source of biomass[].

Propagation

Pre-soak the seed for 12 hours in warm water and sow in mid spring in a greenhouse. Germination should take place within 10 days. When they are large enough to handle, prick the seedlings out into individual pots and plant them out after the last expected frosts.
The seed can also be sown in situ in late spring though it may not ripen its seed in a cool summer.