Bean

The common bean, Phaseolus vulgaris, is an herbaceous annual plant in the family Fabaceae which is grown as a pulse and green vegetable. The common bean can be bushy, vine-like or climbing depending on the variety being grown. The leaves grow alternately on the stems, are green or purple in color and are divided into 3 oval leaflets with smooth edges. The leaves can grow 6–15 cm (2.4–5.9 in) long and 3–11 cm (1.2–4.3 in) wide. The common bean produces white, pink, lilac or purple flowers which are approximately 1 cm (0.4 in) in diameter, and bean pods 8–20 cm (3.1–7.9 in) long and 1–1.5 cm (0.4–0.6 in) wide which can range in color from green to yellow or black to purple. Each pod contains 4-6 smooth, kidney-shaped beans. Common bean plants are annual plants and last only one growing season and range greatly in size from the bushy varieties 20–60 cm (7.9–24 in) in height; to vines or runner beans which can reach 2–3 m (6 ft 7 in–9 ft 10 in) in length. The common bean includes many varieties and may be referred to as bush bean, dry bean, dwarf bean, field bean, French bean, snap bean, garden bean, haricot bean, kidney bean, pole bean or string bean. The plant originates from the Americas.


The common bean is used as a pulse and green vegetable eaten fresh or cooked. The beans can be dried, cooked in sauce and canned.


Basic requirements Common beans are warm-season crops and should be planted after all danger of frost has passed and the soil has warmed. Beans will grow best at soil temperatures between 15.5 and 29°C (60–85°F) and are sensitive to cold temperatures and frosts. Beans will grow best in a fertile, well-draining soil with a pH between 6.0 and 6.75 Beans will perform best in full sunlight. Varieties Common beans can either be bush or pole varieties. Bush beans will grow erect without any support and require less care than pole varieties. Pole beans grow vertically on a support and are generally easier to harvest. Most type of bean are now available as both bush and pole varieties. Some green bean varieties may be referred to as “string” beans. This name is a reference to older varieties which produced a stringy fibre along the seam of the pod. Modern cultivars were bred which did not produce this substance and which are commonly referred to as “snap” beans due to the ease with which the green pods can be snapped in two. Sowing seeds Beans should be direct seeded in the garden in when the soil has reached a temperature of at least 15.5°C (60°F), with the optimum temperature for germination being between 15.5 and 29°C (60–85°F). Planting at cooler temperatures leads to slow germination and promotes seed rotting. Seeds should be planted 2.5–3.5 cm (1–1.5 in) deep. Bush beans should be planted 5–10 cm (2–4 in) apart allowing 0.6–0.9 m ( 2–3 ft) between rows. Pole beans can be planted in both row and hills. In rows, seeds should be spaced 15–25 cm (6–10 in) apart allowing 0.9–1.2 m (3–4 ft) between rows. For a continuous harvest of beans over the summer months, make new plantings every 2–3 weeks. Poles and trellises Pole beans should be provided with a pole or trellis to climb on to support the weight of the pods and allow light to penetrate to all parts of the plant, helping to prevent disease. Bean poles should have a rough surface to help the plant to grip and should be 1.8–2.1 m (6–7 ft) long. Three or four poles can be used to form a tripod onto which the plants can be trained. Bean trellises can be constructed easily using posts (or a tripod arrangement of poles), wire and twine. Position a post at either end of the area in which you wish to plant a row of beans and connect with two lengths of wire. The first wire should be approximately 13 cm (5 in) from the ground, and the second 1.5–1.8 m (5–6 ft) from the ground. Finally, use the twine to create a V-shaped trellis by tying the twine to the bottom wire, bringing it up to the top wire and looping it back down around the bottom wire. Continue to zigzag the string all the way along the wires to the second support before tying the twine off. A rough textured twine is best as it will encourage the plant to climb and twine around it. Pinch back the growing tips of the plants once they reach the top support to encourage the plant to branch. Harvesting Beans are generally ready for harvest approximately two weeks after bloom. The beans should be harvested just before the seeds are mature and before they form bumps on the pod. The pods should be firm and snap when they are bent. Pick beans every 2–3 days to ensure the plants remain productive. Pinch beans rather than pulling to avoid damaging the plant. Cut pole beans from the plant using scissors.


CABI Crop Protection Compendium. (2008). Phaseolus vulgaris datasheet. Available at: http://www.cabi.org/cpc/datasheet/40626. [Accessed 06 November 14]. Paid subscription required. Drost, D. (2010). Beans in the Garden . Utah State University Cooperative Extension. Available at: https://extension.usu.edu/files/publications/publication/HG_Garden_2005-08.pdf. [Accessed 06 November 14]. Free to access. Lerner, B. R. (2001). Growing Beans in the Home Vegetable Garden. Purdue University Cooperative Extension Service. Available at: http://www.hort.purdue.edu/ext/ho-175.pdf. [Accessed 06 November 14]. Free to access. Schwartz, H. F., Steadman, J. R., Hall, R. & Forster, R. L. (2005) Compendium of Bean Diseases. Available at: http://www.apsnet.org/apsstore/shopapspress/Pages/43275.aspx. Available for purchase from APS Press.