The green bean (Phaseolus vulgaris) is a tropical summer crop that comes in 2 forms – bush beans and runner beans. This legume is easy to grow and doesn’t need a lot of space.
Their high nutritional value is the reason to promote them for the market or to keep them in your vegetable garden. They are a good source of vitamins like vitamin C, A and K, folate and riboflavin, and minerals like iron, calcium and magnesium, and add dietary fibre to your diet. It is another versatile vegetable that can be eaten raw or cooked, in various dishes.
Due to their ability to fix nitrogen in the soil, which helps to build nutrients, they are also an important plant to add to your crop rotation system.
Planting period – The green bean is a summer crop, and is mostly planted during the spring and summer. If you live in temperate, frost-free area, you can produce green beans throughout the year, but your yields can be smaller during the cooler months.
Daytime temperatures – between 24°C – 27°C
Minimum temperatures – between 14°C – 16°C
Due to its tropical origins, the green bean doesn’t do well at temperature below 10°C and is very sensitive to frost.
Temperatures above 35°C accompanied with dry winds can also lead to flowers and pods dying off, leading to poor yields.
- The green bean can be grown in a range of soils from sandy to heavy clay soils, but for the best yields, they prefer sandy loam soils.
- Avert from soils making a crust since this can negatively affect seedling emergence.
- They prefer deep, well drained soils.
- Waterlogged soils can lead to damping off and other diseases.
- The optimal pH value is approximately between 6 and 6.5.
- Rotate your green beans with other non-leguminous crops to avoid the transmission of diseases like bacterial blight, anthracnose and fusarium wilt.
- The soil should be loosened properly by either ploughing or a hand hoe.
- Break up all clods until the texture of the soil is evenly tilth.
- Incorporate old manure, compost or fertiliser thoroughly into the soil during preparation.
Cover crops can be planted and worked into the soil 4 to 6 weeks before the green beans are established. A soil analysis should be done before applying fertiliser.
GENERAL FERTILISER RECOMMENDATIONS
- Under normal conditions between 100 kg and 120 kg of nitrogen per ha is applied in splits.
- 60% of the total should be applied before planting and the remainder should be applied by the 4th week after planting.
- Phosphorus is normally applied at planting. Usually between 30 kg to 65 kg per ha should suffice.
- Under normal conditions, a potassium application of 50 kg to 95 kg per ha should be adequate.
- Bush beans need 60 cm between rows and 5 cm between plants in a row (32 plants per m2).
- Depending on the spacing and the grade of seeds, this means you need to plan for between 60 kg and 100 kg of seed per ha when you plant.
- More space is needed for runner beans – 1 m between rows and a space of 10 cm between plants in a row.
- Up to 3 plants can be trellised to 1 support to save money.
- The spacing between different cultivars might differ, so consult your seed packet and remember to allow space for picking.
- Green beans sown directly will establish well.
- Plant depth – plant at a depth of between 10 mm to 15 mm. Consult your seed packet.
- The green bean needs regular irrigation, but the most important watering period is during the flowering and pod stage.
- The water needs of beans depend on the climatic and soil conditions.
- Light sandy soils need more regular watering.
- The green bean doesn’t like watering on the seed while germinating.
A PRACTICAL GUIDE TO FOLLOW:
- Water properly directly after sowing and wait for emergence.
- Emergence to flowering – 25 mm to 35 mm of water every 10 days.
- Flowering to picking – 25 mm to 35 mm every 7 to 10 days.
- It takes between 60 to 90 days for green beans to mature.
- Green beans for the market are picked by hand.
- Only beans that are ready should be picked.
- The pods should be bright green and fleshy, and the seeds should be small and green.
- To know when the bean is ready, cut open the pod lengthwise.
- The seeds in the pod should be well developed, but not hard.
- The beans ripen quickly in warm weather and it is important to harvest every day to ensure quality.
- Harvest early in the morning or late in the evening and keep the beans out of the heat, otherwise they might wilt.
- To keep your green beans fresh for the market, keep them cooled and stored at between 4°C to 7°C.
- Beans don’t have a long shelf life, and are not well suited to storage.