Coffee cultivation and harvesting: Picky plants with a certain standard
The so-called coffee belt runs around the equator, between the two Tropics of Cancer, i.e., the 20th parallel south of the equator and the 20th parallel north: this is where the coffee bushes whose fruits are enjoyed so much around the world grow.
Coffee cultivation – important climatic requirements
Coffee bushes, which can easily grow into trees, prefer balanced climatic conditions – so there should be no significant temperature fluctuations, but also not too much sun or heat. At average temperatures of 18 to 25°C, the plants feel comfortable. Below 13°C, it becomes just as tricky as with heat above 30°C – the coffee bushes cannot tolerate frost at all. All these requirements are met by the highlanders in the coffee belt, who are thus recommended for coffee cultivation. However, the optimum height varies depending on the variety: While Arabica, for example, grows best at altitudes between 600 and 1,200 m, 300 to 800 m is sufficient for Robusta.
Another criterion that should not be underestimated is rainfall: it should rain between 250 and 300 millimeters per month, which corresponds to an annual quantity of 1,500 to 2,000 millimeters. If the yearly precipitation falls below 1,000 millimeters, irrigation is required – coffee cannot be grown at all from 800 millimeters downwards. Here, too, the different varieties must be considered separately: For example, Robusta requires more water than Arabica. Basically, the soil should be loose, permeable, and deep; humus is best in the upper layer, i.e., a slightly acidic to neutral soil environment. Since wind and sun damage in excess, shade trees and hedges are often planted for protection.
From the seed to the bean – an overview of coffee cultivation
As a rule, seeds about eight weeks old are used to grow coffee. The bean is freed from its pulp and husk and pressed a few centimeters deep into the ground. Ideally, the soil is slightly acidic. It takes five to six weeks before the seedlings can be replanted in separate containers. Another eight months later, the young plants can be put out – at a distance of 1.5 to 4 meters. Now it takes time and care: coffee plants can grow more than 3 m tall, which makes harvesting all the more difficult. That is why they are cut back to a height of 1.5 to 3 m – after all, in many areas, the coffee harvest is still done by hand.
After four years, the Arabica variety can be harvested for the first time, but it takes ten years for a coffee bush to reach its optimum yield. This amounts to a quantity of 1 to 1.5 kg of coffee beans per plant. Coffee plants can grow to 50 to 60 years and even older. But after 15 to 20 years, their yield usually diminishes, so they are cleared and replaced.
The coffee harvest requires patience and tact: although it usually occurs only once a year, it takes almost three months, as the coffee fruits on the same bush ripen at different times. North of the equator, therefore, the harvest takes place from July to December, in southern climes from April to August. This peculiarity of coffee cultivation has a direct impact on the appropriate harvesting methods and the quality of the coffee to be obtained:
This method involves regularly checking the degree of ripeness of the fruit and then plowing the appropriate coffee cherries by hand. This method of coffee harvesting is extremely labor and time-intensive, but it produces the highest quality: only ripe coffee fruits are harvested and processed.
In this variant of coffee harvesting, all the fruits of a plant are stripped at once, so that they fall on a cloth on the ground. It is obvious that the pickers move faster this way, but unripe coffee fruits also get into the harvest – so the quality suffers.
Accompanied coffee harvesting is even faster, but it also reduces the quality: Here too, unripe fruit gets into the harvest. Besides, harvesting machines cannot be used everywhere, the growing areas are either not suitable, or the investment cannot be realized. Only in huge coffee plantations is such an investment profitable.
Criticism of intensive coffee cultivation
The consequences of intensive coffee cultivation for the environment must not be ignored: In order to increase the yield and thus compensate for the fall in coffee prices, more and more large plantations were established in monoculture and without the shade that space demands. The consequences are dramatic: on the one hand, landslides occur during heavy rainfall when plantations are set up on slopes, and on the other hand, biodiversity is dramatically impaired. Migratory birds no longer find shelter; the balancing interplay of pests and beneficial insects is disturbed. Fertilizers and pesticides are supposed to contain the resulting diseases and pest infestation – and put additional strain on the environment.
The solution: Reviving traditions
Back to the origins: Coffee was once grown in the shade of large trees so that the natural habitat was hardly affected, and a high level of biodiversity was preserved. Banana trees, grapefruit, or avocado trees are particularly suitable for this purpose. A polyculture, such as with pineapple, is also useful. This not only reduces the need for fertilizer but also allows several food and export goods to be harvested at the same time. It is crucial to train the coffee farmers regularly – and to guarantee the prices.