Planting and harvesting green beans

Visual appeal plays a major role in the breeding of beans. Darker green, slender, straight beans have become more popular of late.

Planting and harvesting green beans
An example of a green bean plant exhibiting concentrated bearing.
Photo: Bill Kerr
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These attributes have nothing to do with taste; they are simply more pleasing to the eye. Consumers are highly attuned to choosing according to appearance, and this choice is usually made in an instant.

A farmer needs to take this into account when selecting a variety and a packaging method.

The downside to this trend is that harvesting and packing require more labour. And higher labour costs, in turn, have led to the breeding of varieties with more concentrated bearing, which allows each worker to harvest more in a day.

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In some cases, the cost of labour has prompted farmers to opt for mechanical harvesting.
The loss of many South African bean producers due to labour costs has affected supply and demand, causing the price of beans to rise.

Optimising labour
The number of workers needed to harvest beans can work in favour of a farmer who has a labour-intensive enterprise and periods when the workers have little work to do. Beans can provide a useful way of utilising this spare capacity.

When calculating the labour requirements for harvesting, work on about 1kg of beans harvested per running metre of row, depending on conditions.

The best approach is to determine how much each worker can harvest in a day and turn the task into piecework, allowing the worker to go home after harvesting the required amount. With a good crop, this can be about 100kg/ day.

(An easy way of estimating output is to establish how much an efficient employee can harvest in half-an-hour and multiply this by 12 for a six-hour day.)

When using this incentive method, check that your workers do not miss harvestable pods or handle the plants too roughly in their haste to reach the target.

Beans take approximately 60 days from planting to harvest. When planning your crop, take into account how long the beans will be in a harvestable state, bearing in mind the characteristics of the variety and to what stage of maturity you want the pods to develop.

As maturity advances, the developing seeds will produce bumps on the exterior of the pods, which can be off-putting to some consumers. In addition, the gel between the seeds will start to become spongy, which downgrades the crop.

More frequent harvesting
The frequency of planting for a constant and uniform harvest will depend on the variety and the stage of harvest.

With some varieties, you can harvest more frequently, choosing the optimal stage each time to ensure the beans are at their best. This will also encourage the plant to continue filling pods and thus produce a larger crop.

You will have to compare the higher harvesting costs with the benefits to determine whether this approach is worthwhile.

Bill Kerr is a vegetable specialist and a breeder of a range of vegetables.