October 26, 2022

A guide to the Ruiru 11 coffee variety


According to the International Coffee Organisation, Kenya produced 775,000 60kg bags of coffee in 2020 – making it Africa’s fifth-largest coffee growing country that year. However, production volumes have been steadily declining in recent years for a number of reasons.

Many popular coffee varieties in Kenya include SL-28 and SL-34, which were first introduced to the country’s farmers more than 90 years ago. While SL varieties are high quality, they are also highly susceptible to various pests and diseases – making them difficult for farmers to grow.

However, as part of a wider discussion on introducing more disease-resistant and climate-resilient varieties to Kenya’s coffee sector, farmers are starting to grow others. One of these is Ruiru 11 – a high-yielding dwarf F1 hybrid which is more resistant to a number of pests and diseases.

To find out more about Ruiru 11, and whether or not it will become more widespread, I spoke to two local coffee farmers. Read on to learn what they had to say.

You may also like our article exploring two popular Kenyan coffee varieties: SL-28 and SL-34.

Coffee berry disease Colletotrichum kahawae infection on coffee cherries in Kenya

The origins of Ruiru 11

As with many other hybrid varieties, Ruiru 11 was developed because of the increasing prevalence of pests and diseases. The most prominent example was a coffee berry disease (CBD) epidemic in 1968, which destroyed around half of Kenya’s coffee production that year.

CBD is caused by the Colletotrichum fungus, which turns cherries brown or black – leading to rot and premature drying. Ultimately, this has a detrimental impact on a coffee plant’s yield and quality.

In response to rising cases of CBD, a coffee station in Ruiru began breeding coffee varieties in the 1970s which were more resistant to the disease – as well as still producing satisfactory volumes of high-quality coffee.

One of these varieties was Ruiru 11 – a disease-resistant dwarf F1 hybrid which could be grown at different altitudes. According to World Coffee Research, the variety was developed using genetic material from many different varieties – including a Catimor female parent and a selection of K7, SL-28, N39, and Sudan Rume male parents.

These varieties were largely chosen for their higher levels of resistance against CBD, as well as coffee leaf rust (CLR) – a fungus which eventually kills coffee plants. However, alongside their disease resistance, these varieties also give Ruiru 11 a reputation for high yields and good quality coffee.

An elderly Kikuyu lady picks Ruiru 11 coffee in Kenya, Nakuru District, Subukia Valley.

When was Ruiru 11 first planted?

Ruiru 11 was first introduced to Kenyan coffee farmers in 1985, which marked a significant change for the country’s coffee sector.

Compared with other varieties, which are more slow-growing, Ruiru 11 generally produces its first harvest within two years of planting. Its plants are also small and compact, which means producers can grow more of them in a smaller area.

Watson Wanjau is a coffee farmer in Kenya, who has been producing the variety for the past decade.

“I grow Ruiru 11 on some small parcels of land,” he says. “Because you can plant the variety closer together than others, such as SL-28 and SL-34, you can increase productivity.”

He adds that Ruiru 11 requires fewer fungicides and fertilisers than other popular varieties in Kenya – meaning it’s typically more affordable for farmers to grow than SL varieties.

One of the most significant ways in which Ruiru 11 has proliferated is through top-working. This is when farmers graft new plant material of one variety onto an established root system of another – essentially eliminating the need for producers to plant more Ruiru 11 seeds.

“Top-working is the easiest way of helping more farmers grow Ruiru 11,” Watson explains. “Producers can utilise the already established root systems to convert their plants.”

However, he adds that top-working is still a new concept for many Kenyan coffee farmers, so the level of success can vary widely depending on the producers’ experience levels. Furthermore, rootstock grafting is a complex process which usually requires the assistance of specialists.

In light of this, Watson suggests that producers should first plant Batian, which has some of the same parents as Ruiru 11. Farmers can then graft Ruiru 11 scions (the term for offshoots and twigs) onto the root systems of Batian to make top-working easier.

Africa Kenya Ruiru Coffee pickers empty buckets of cherries at a collection site at Oakland Estates coffee plantation

Are more Kenyan farmers growing the variety?

Symon Sogomo is a coffee farmer at Sogomo Coffee Estate in Trans-Nzoia County, Kenya. The farm grows three varieties, including Ruiru 11, Batian, and some SL plants. 

He explains that when it comes to planting more Ruiru 11, some of the country’s older farmers are somewhat apprehensive – especially when growing Batian for top-working.

“There is a noticeable difference in how Batian and Ruiru 11 both grow,” he explains. 

Kenya’s main annual coffee harvest runs from March to July. So while Batian is a high-yielding plant, it can sometimes produce less coffee in the following harvest – especially if yields were high in the previous year.

“But whenever a new variety is introduced, it will always be viewed differently initially,” he adds. “When I asked some older farmers about when Ruiru 11 was first introduced, they said that farmers didn’t know how to grow it and agronomists didn’t know how to manage it.”

Under optimal conditions, producers can grow up to 3,000 Ruiru 11 plants per hectare, which will produce a consistently high volume of cherries – providing farmers with a number of benefits.

Ultimately, this, as well as other reasons, has led to a sharp rise in demand for the variety.

“It is a variety which Kenyan coffee farmers fully support,” he says. “It was developed in Ruiru, so it is Kenyan variety, rather than others which were brought over by colonists.”

However, as certified Ruiru 11 seeds must be sourced from the Coffee Research Foundation in Kenya (along with all other seeds in the country), supply has not been able to meet demand. Moreover, the research institute has started to shift its focus towards cultivating Batian in recent years.

“My coffee-growing region is relatively young compared to other areas in Kenya, so we plant more Batian than Ruiru 11,” Watson says. “However, many farmers want to plant Ruiru 11, but they can’t source the seedlings.”

At his nursery, Watson tells me he and his team grow Ruiru 11 seedlings obtained from the Coffee Research Foundation. They also supply seedlings to other local farmers to help boost the variety’s production.

Coffee Beans Tree Farm in Ruiru Kiambu County, Kenya

Understanding the challenges of Ruiru 11 production

Although there are clear advantages to growing Ruiru 11, some Kenyan farmers are concerned that its quality is not as high as the SL varieties – potentially resulting in lower prices.

Symon, meanwhile, believes that few consumers would be able to taste the difference between Ruiru 11 and SL varieties. He says this is largely because the former is still considered a “young” variety in Kenya, so its sensory profile is still yet to be fully explored.

However, one of the bigger concerns around Ruiru 11 is its susceptibility to certain pests and diseases – despite the drive behind its cultivation and its supposed resilience.

As Ruiru 11 is often grown alongside other varieties, pests and diseases can actually spread more easily than initially thought to plants in some cases.

“We have had some unusual cases of CLR and CBD on Ruiru 11 plants,” Symon tells me. “Agronomists told us that the genetic materials for these plants were probably not selected to a high enough standard.

“Ruiru 11 which is 100% genetically accurate should be completely resistant to both of these diseases,” he adds.

Watson says that there have been more cases of CBD affecting Ruiru 11 plants, but expert agronomists have warned producers to not treat the plants accordingly. This is largely because the effects of CBD on Ruiru 11 are often non-threatening. 

“We were advised to collect and burn the affected cherries,” he tells me. “However, these cases are still concerning because when it was first introduced, Ruiru 11 experienced these issues. 

“We hope that it is just a normal reaction to being planted with other, more traditional varieties,” he adds.

Alongside a small number of unusual CBD cases, Ruiru 11 is also sensitive to drought stress. The variety’s higher yields are contingent on a significant amount of water – a growing issue considering the rising number of Kenya’s droughts in recent years.

“Producers growing Ruiru 11 need to have an alternative source of water if rainfall is lower than expected,” Watson says. “To produce healthy cherries, the variety needs a lot of water, so it’s important to also have large irrigation tanks and systems in place.”

Ruiru 11 coffee seedlings growing in a nursery

Looking to the future

Considering the increasing demand for Ruiru 11 seeds in Kenya, it’s more than likely that production volumes will grow in the coming years. However, this is mostly dependent on whether seeds will become available to more farmers.

Watson hopes that the Coffee Research Foundation will address this problem in the near future, mainly by cultivating more seeds and increasing producers’ access to them.

He emphasises that top-working is one of the ways in which farmers can supply themselves – and potentially others – with more Ruiru 11 plants.

“More than half of our Ruiru 11 plants were cultivated using top-working,” he says. “Most other Ruiru 11 farmers have done the same.

“Moreover, top-working seems to be working better and better every year,” he adds.

Although top-working can be complex and difficult, if supply chain stakeholders invest in teaching Kenyan coffee farmers the best practices for this process, the country’s Ruiru 11 production could certainly grow.

Coffee sprouts germinating in a nursery

Thanks to its generally solid tolerance for a range of major diseases, there is no doubt that Ruiru 11 will continue to be prominent across Kenyan coffee production. Its increased resilience, as well as its high yields and cup quality, make it well worth growing for many of the country’s farmers.

Some researchers and producers also believe that as the variety evolves, it will continue to acclimate to Kenya’s soil and climatic conditions, and more research about how to best cultivate it will be summarily conducted. However, ultimately, whether or not this happens will all depend on one thing – seed availability.

Enjoyed this? Then read our article exploring land succession in Kenyan coffee production.

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