Highs and lows, expert guide on farming yellow beans in Kenya

Highs and lows, expert guide on farming yellow beans in Kenya Photo courtesy

Bean (Phaseolus vulgaris) is one of the world's most important legumes, providing nutrients to many people. It is a staple food crop in Kenya, ranking second only to maize. The crop is grown in almost every region of Kenya. However, the main bean-growing provinces are Eastern, Nyanza, Central, Western, and Rift Valley.


Bean crops require very little care and add nitrogen to the soil.

Bean Varieties

A wide range of bean varieties are grown in Kenya. These include the following;

  • Rose Coco
  • Mwitemania
  • Wairimu
  • Mwezi Moja
  • Canadian W
  • KK 15



Bean Ecological Requirements

  • Soil– bean crop thrives in a well-drained soil which is rich in organic matter, weed free and has an optimum PH of 6.5 – 7.5. Growth is poor in waterlogged soils.
  • Altitude– the crop does well at an optimum altitude range of up to between 1000-2100M ASL. It however tends to grow and mature faster in low altitude zones.
  • Rainfall– a well distributed annual rainfall of between 800-2000mm is suitable for the rain fed production. Irrigation should be done if rainfall is inadequate. Too much rain or long dry spells are not conducive and reduces yields. Excessive rainfall during flowering causes flower abortion and increased disease incidences. Dry weather conditions are needed during harvesting.
  • Temperature– beans grow in temperatures ranging from 15-33 degree centigrade. However, an optimum growing temperature of 20-25 degrees centigrade is essential. Relatively high temperatures affect flowering and pod setting processes. The crop is very sensitive to frost.

Bean Planting

Seeds are used for propagation, and it is best to use certified or disease-free seeds. Wrinkled, damaged, or diseased seeds should not be planted.

If rain-fed production is used, planting should begin as soon as the rains begin. Delays in sowing may result in crop failure or reduced yield.

Seeds are planted at a depth of 1-2 inches and a spacing of 40*15 cm (2 seeds per hill) or 30*15 cm (1 seed per hill).

The crop can be grown alongside other crops such as maize. Seeds germinate in 4 to 7 days, depending on variety and environmental conditions.

NB: Do not plant beans where the soil nitrogen content is too high or where green manure crops have been grown.

Beans Pests and Diseases Management

Pests

  • Cutworms – these are brown or black caterpillars usually found in the soil, which cut the stem of younger plants below the soil surface.

DRESS seeds with SHIELD 600FS 3 ml/kg, DRENCH soil with PROFILE 440EC 3 ml/l

  • Bean fly – the larva tunnels into the plant stem damaging the vascular tissue, causing reduced plant vigour and petiole droop in older crops. Severe infestations can lead to death of seedling. Crops are at a greater risk for 3 – 4weeks after emergence, however, later on, crops can be attacked.

DRESS seeds with SHIELD 600FS 3 ml/kg, DRENCH soil with PROFILE 440EC 3 ml/l, SPRAY  LEXUS 247SC 8 ml/20l to kill the adults.

  • Red spider mites – these are tiny reddish yellow pests found on the undersides of the leaves. Their feeding leads to formation of yellow stipples on leaf surfaces they form webs in cases of heavy infestations.

SPRAY ALONZE 50EC 5ml/20l

  • Aphids – these are soft bodied, green, black or brown insects which suck plant sap. Infested leaves curl and crinkle. They also attack the pods. As they feed, they excrete honeydew which encourages the development of sooty mold which reduces photosynthetic area.

SPRAY LEXUS 247SC 8 ml/20l, SPRAY JAMBO CLEAN 5 ml/l to get rid of the sooty mold.

  • Leaf miners – the larva (caterpillar) mines under the leaf surface, resulting into development of mines / winding trails. Heavy infestations lead to death of the leaves.

SPRAY ALONZE 50EC 3 ml/20l

  • Pod borer – African bollworm is the most common borer which feeds on leaves, flowers and pods thus damaging them. It bores holes on pods and feed on the seeds, with its head inside the pod and the rest of the body outside.

SPRAY PENTAGON 50EC 10 ml/20l

  • Whiteflies – these are white insects which suck plant sap. Infested leaves curl, become distorted and eventually drop. They secrete honeydew as they feed which facilitates the development of sooty mold on the leaves affecting photosynthesis.

SPRAY PROFILE 440EC 1.5 ml/l, SPRAY JAMBO CLEAN 100ml/20l to clean the sooty mold if need be.

  • Thrips – they feed on leaves and flowers by sucking the sap. Heavy infestations lead to flower and flower buds abortion. Leaves fall off.

SPRAY ALONZE 50EC 5 ml/20l or PROFILE 440EC 30ml/20l

 

Bean Nutrition

For optimal production, it is critical to provide the crop with adequate nutrients, both macro and micronutrient elements. This is because depriving the crop of these nutrients causes it to become weak and vulnerable to pathogen attack. This leads to a lower yield.

It is recommended that you use a phosphorus-rich fertilizer when planting. Manure can also be applied to the soil, depending on the amount of organic matter present. To improve plant nutrient uptake while also stimulating growth, mix 1 kg Humipower into 1 ton manure or 50 kg basal fertilizer.


 



Top dressing should be done about 4 to 5 weeks after germination. CAN is used or some basal fertilizer rich in Calcium, Boron, and Nitrates, which should also be mixed with HUMIPOWER at a rate of 1 Kg of Humipower per 50 kg of basal fertilizer.

However, these basal fertilizers should be supplemented with foliar fertilizers because they contain a diverse range of nutrient elements that are essential to plants.
Maturity, harvest, and post-harvest management

Beans can be harvested 70 to 120 days after sowing, depending on the variety. Others take shorter periods. When the plants reach maturity, their leaves turn yellowish to brown or fall off.

Beans can be harvested green or dry.

Dry harvesting involves harvesting pods when they are completely dry. However, if they have withered but remain moist, they can be harvested and sun dried. Plants can also be uprooted if the majority of the pods are ready to harvest.

Pods that are completely dry split open, exposing the dried beans, which is a risky time to harvest, so careful timing is required.


Dry beans are stored in treated gunny or PICS bags, which help to prevent significant damage from storage pests. To prevent pest damage while in storage, it is recommended that the seeds be treated with an insecticide, such as Actellic Super. Bags should be placed on pallets rather than directly on the floor.

Green beans can be refrigerated for 8 to 10 days, while dried beans can be kept in a cool, dry place for a year or more.

Types of Yellow Beans

There are two main types of yellow beans grown in Kenya – pole beans and bush beans. Within each type, several popular varieties are cultivated:

Pole Yellow Beans

  • Yellow roman. Produces bright yellow, flat pods on vigorous climbing vines. Matures in 75 days. Great flavor.
  • Marvel of Venice. Heavy yielding Italian heirloom with tender, stringless pods. Tolerates cool conditions. 
  • Gold nectar. Commercial variety with long, smooth, golden-yellow pods. Good pest resistance. 
  • Kentucky wonder. American heirloom with curved, meaty pods. Grows well in mid-altitudes.
  • Monte gusto. Prolific variety from Zambia with yellow-green pods. Matures in 65-70 days.

Bush Yellow Beans

  • Brittle wax bush snap bean – Pods harvest yellow and become tan colored. Great for canning.
  • Pencil pod black wax bean – Produces long, slender, bright yellow pods. Delicate flavor. 
  • Golden butter wax bush snap bean – Compact bush with smooth, golden pods. Tolerates humidity well.
  • Goldrush bush snap bean – Commercial variety yields straight, yellow and purple-striped pods.

The pole beans need staking while bush types are free standing. Both offer delicious bean varieties suited to Kenyan growing conditions.

Ecological Requirements for Farming Yellow Beans

Yellow beans grow best in certain conditions for optimal production:

Requirement Description
Altitude From sea level up to 2,400 meters above sea level
Rainfall At least 500-800 mm well distributed over the growing season
Soils Deep, well-drained sandy loams or clay loams with good fertility
pH Ideal soil pH is 5.5 to 7.5
Temperature 18°C to 27°C is preferred but some varieties tolerate higher and lower temperatures

 

Yellow beans thrive in most parts of Kenya, with the exception of very arid and semi-arid areas, due to their climate requirements. They thrive in highland areas with high rainfall, moderate temperatures, and fertile volcanic soils.

With irrigation, yellow beans can thrive in drier lower zones. Soil fertility is critical; the plants require sufficient nitrogen, phosphorus, and potassium for vigorous growth and maximum pod set.
 

Best Farming Practices for Yellow Beans

  • clear land thorougly
  • plough deeply
  • harror repeatedly
  • shape beds and furrows or ridges for planting
  • take a soil test
  • plant at the onset of a rainy season
  • sow seeds 2-5cm deep and 10-40cm in rows and 60-90cm apart
  • plating density of 100k plants per 1acre
  • install stakes for climbing
  • bush types can be left to grow along the ground
  • staking improves aeration
  • ensure consistent moisture
  • critical times for water are flowering
  • drip irrigation is most efficient method in drier areas
  • mulch well to conserve soil moisture
  • weed early
  • shallow culitvation
  • later, remove manually
  • apply organic manure
  • top dress with CAN  4-6 weeks after emergence
  • folier feed with liquid fertilizer
  • scout regularly and identify diseases promptly
  • apply recommended pesticides
  • begin pick young post for sales during harvesting
  • use sharp blades during harvesting
  • harvest every 2-3days
  • pick early in the day before pods lose turgidity
  • leave mature dry pods as long as possible for seeds
  • harvest dry pods when they turn yellow
  • dry pods further in the sun before removing seeds