French Beans Farming

French beans, also known as snap or green beans, and locally in Kenya as mishiri, are a major export crop. Interest in french beans farming is fast-growing for both fresh consumption and processing (mainly canning and freezing). French beans contain protein, fat, calcium, iron, phosphorus, vitamins A, B, D and starch. French beans grow well in lower midland to lower highland zones of altitudes ranging from 1500-2100 metres above sea level.

How To Grow French Beans
How to grow french beans (green beans or mishiri) quite straight forward. Rain-fed cultivation is possible in areas with well-distributed, medium to high annual rainfall of 900-1,200mm per annum. However, to maintain continuous supply especially during the off-season, irrigation is essential. Up to 50mm of water per week is required. French beans can grow in different soil types, ranging from sandy, loam to clay. The optimum temperature for production is 20-25°C. However, the beans survive in temperature ranging from 14-32°C depending on the variety. Seedlings will not tolerate temperature lower than 10°C. They, however, grow well on friable (easily crumbled), silty loam to heavy clay soils,. which are well-drained and high in organic matter.

Soil Test
Before planting the french beans, consider knowing the nutrient & chemical status of your soil. The optimum soil pH is 6.5 to 7.5, but french beans can tolerate a low pH of up to 4.5. Below a pH of 4.5, plant growth is impaired through limitation of development of the rhizobium bacteria that are responsible for the nitrogen fixation in the galls formed on the bean roots. It’s advisable to carry out a soil test before planting. Various varieties are grown mainly for export, and they are determined by the market preference.

French beans are sown directly into the seed bed. The land should be ploughed and harrowed properly just before planting. With irrigation, French beans can be grown all-year round but the main export season is from October to May. Spacing should be single rows of 30x15cm (a seed per hole) or double rows of 60x30cm. The spacing will depend on the variety, soil fertility, water availability as well as climate. It is advisable to plant in blocks of about four rows separated by a path of about 50cm.

Fertilizer And Manure Application
French beans seed rate required is 25-60kg/ha (10-24kg/acre) of certified seeds depending on the variety. Apply 200kg/ha (80kg/acre) DAP along the rows before planting or as per the recommendations given in your soil test results. Contact between fertilizer and seed should be avoided by mixing the former thoroughly with the soil in the planting furrow. Apply 150kg/ha (60kg/acre) Calcium Ammonium Nitrate (CAN) for top-dressing twice or as per the recommendations given your soil test results. First when two to three leaves appear and the second at the beginning of flowering.

Supporting French beans
Climbing varieties that grow to about 1.8m (6ft) high need to be supported. This is done by use of trellises, poles, or other means at least 200cm (8ft) high.

Pests And Diseases
The main diseases in french beans farming include rust, angular leaf spot,root rots, bacterial blights, anthracose, bean common mosaic virus, powdery mildew and downy mildew. To control these diseases, farmers are advised to use crop rotation, tolerant varieties, field hygiene, health certified seeds, and recommended insecticides and fungicides.

Harvesting French Beans
Picking of pods begins six to eight weeks after planting, depending on the area and variety, and continues for about one to two months. The pods are carefully picked, and not pulled from the plants, and should have the stalk attached to them. Picking should be done at regular intervals depending on buyer specifications.

Harvesting may be done twice a week for the fine beans and three times a week for the extra fine beans. This continues for around three weeks. One gets yields of nine to 15 tonnes/ha and six tonnes/acre in 21/2 months.

French beans farming market in Europe