Just like any other plant, coffee trees are affected by time. After a certain period, they will reach a stage where their output and productivity diminish.

This is a normal occurrence for just about any living organism; however, it presents a significant challenge for millions of smallholder coffee farmers across the world.

As a result, farmers are looking for financially sustainable ways to preserve and improve the longevity of their crop. At a time when many coffee producers lack fiscal stability, completely replanting their fields is not an option. Aside from the associated costs, it will also take a long time for new plants to bear fruit and become profitable.

Alongside decreases in productivity, the impact of climate change and other external factors (such as disease) mean that older, pre-existing plants may not provide the income security that they once did.

To learn more about the situation and how a new agricultural technique known as “top-working” could help, I spoke to coffee producers in Kenya. Read on to find out what they said.

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Top-Working In Kenya 

In Kenya, the most common arabica varieties include SL28, SL34, and K7. These varieties yield good-quality beans, and can remain productive for a long period of time.

However, as traditional varieties that have been present in the country for decades, they have not been specifically developed to be resistant to climate change or unpredictable weather patterns.

As a result, whole cropping seasons in the country have been affected, and many farmers have suffered great losses in terms of crop yield and plant productivity.

As well as this, two of the most common varieties in Kenya (SL28 and SL34) are highly susceptible to both coffee leaf rust and coffee berry disease (CBD).

Replanting entire fields with new, resilient varieties is not an option for many producers. As well as being incredibly expensive, the opportunity cost to producers is enormous. These varieties won’t start producing for two full years (at a minimum) after planting.

As such, many producers in Kenya are practising a farming technique currently known as “top-working”. This involves utilising the established stumps of these older, traditional plants to grow new, resilient, and highly productive trees.

While this is functionally similar to grafting, the major difference is that top-working actually allows the farmer to continue harvesting cherries while the new variety is developing.

The principle behind top-working is very simple: take the already-established root system of the existing, older plants, and combine it with the disease resistance and higher yields of new varieties. The result? A “brand new” coffee farm, full of modern, resilient, and productive plants that already have established root systems.

Two varieties that are being commonly used in Kenya as the “scions” (the new plants that are grafted onto the older varieties) are Ruiru 11 and Batian.

Both are either resistant to or tolerant of CBD and coffee leaf rust, and they are ultimately more productive than the “classic” varieties that have been planted in Kenya for decades. Both also start bearing fruit after just two years, as opposed to three.

Sarah Wambui is a member of the Nyumba Kumi coffee group. “People need to be taught about the advantages of this system,” she says. “There are some who are losing three or more harvests by uprooting the existing plants to plant new seedlings of Ruiru and Batian.

“This is wasting money, and causing some people to feel discouraged… however, with this method of renewal, there is absolutely no loss of crop,” she explains. “There are also more nurseries coming up that are providing Ruiru and Batian scions for grafting, making the process much cheaper and accessible for ordinary farmers.”

How Do You Do It? 

Top-working is a vegetative propagation method where producers convert mature arabica trees of less productive varieties to modern ones such as Ruiru 11 or Batian – without uprooting or replanting.

The process is relatively straightforward. Producers identify and mark the trees that are to be renewed. Suckers (which are shoots that rise out of the ground near the base of the plant, from the root system) are then allowed to grow on these trees and pruned as necessary.

After some healthy suckers reach six months old, scions of Ruiru 11 or Batian are then grafted on. These scions should have a single node (which is the point where cherries grow) and be at least as thick as a pencil.

At least two suckers should be grafted to each tree to increase the chances of success. The grafted area is then bound with polythene tape to keep the scion in place and allow it to heal successfully.

Once healed, the polythene tape will fall off, indicating that a new stem has grown. From here on, this new stem is treated just like a normal stem, and it will eventually start flowering and bearing fruit.

However, while it grows, the producer can harvest from the other, older stems on the tree, meaning they don’t lose their income source during this time.

After the new stems successfully bear fruit, the old tree can then be pruned off through full stumping, leaving a new, productive plant of the resistant variety.

While some producers carry out this process, it is generally carried out by qualified agricultural officers in Kenya. They will inspect the current situation of the farm before advising on the most sensible way of top-working, before beginning the grafting process themselves.

Anthony Ngunyi is a coffee producer who inherited his farm from his grandfather. He recently successfully “converted” the existing crops to Ruiru 11.

He says that the agricultural officers carrying out top-working are willing to teach producers about the process of grafting, which he says is reasonably straightforward.

“The [agricultural officers] from the Ministry of Agriculture will do it for you once and then show you how to do it yourself,” he explains. “This is useful, because more farmers will adopt this method and will benefit as a result. 

“I have started grafting just a few plants; hopefully, by the end of the season, I should be very familiar with the process.”

Sarah says: “Within two years, farms are totally renewed, meaning higher productivity at a minimal cost. This is the goal of any farmer, so I hope that people embrace this renewal process. It can take less than a week, and the effects [can] last forever.”

To summarise, top-working allows producers to massively improve the resilience and yield of a coffee farm without interfering with normal cropping patterns.

It is a great way to change plants from one variety to another without costly replanting efforts, and it means producers can mitigate the financial cost of changing variety by growing old plants among the new.

Furthermore, by using established root systems from the original stumps, these new plants are also less likely to struggle under the weight of a heavy crop. 

However, it’s important to note that this method should not be undertaken without appropriate training and expertise. Even though it is relatively straightforward and can be highly beneficial, top-working should be first carried out by someone who is qualified to do so.

Enjoyed this? Then read How Coffee Producers Can Adapt to Climate Change

Photo credits: Meklit Mersha, Sicafe S.A. De C.V

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