What is grafting in coffee?
We often think of coffee as just coffee, this magical bean that happens to taste great and energise us, but little do we stop to think about what coffee is, and where it actually comes from. For starters, coffee is a seed. It’s the seed of a small cherry-like fruit that grows on trees all around the world. The seeds are extracted from the fruit, dried, and then finally roasted so that we can brew and enjoy it in the form of coffee.
Just like all fruits, there are many different kinds of species and varieties, coffee is much the same, some of course are more common than others. Over the years, coffee producers have selectively bred and experimented with these varieties to cater to different consumer preferences.
As the demand for high-end specialty coffee surged, producers sought new ways to distinguish their product in a competitive market. One successful technique has been grafting, a practice that has proven to be as ‘fruitful’ as it is ingenious, enabling the cultivation of coffee plants that not only stand out for their quality but also for their resilience and distinct flavours.
What is grafting?
Grafting is a propagation technique employed by agronomists to combine desirable traits from different plants. This method involves taking a piece of tissue, known as the scion, from one plant and attaching it to another plant, referred to as the rootstock. The goal is to create a new, hybrid plant that exhibits specific characteristics from each of the parent plants. Grafting is especially effective for rapidly integrating distinct qualities from related plants and is most successful with plants within the same species or closely related genera.
Developing a new plant variety through traditional breeding methods, such as cross-pollinating often takes several years to decades. It’s a costly and expensive process doesn’t take into account the financial needs of farmers and producers. In contrast, grafting offers a more reliable, predictable, and quicker way to achieve the same result.
Grafting in coffee
In coffee cultivation, grafting is employed to develop varieties that combine the best attributes of their parent species or varieties, such as enhanced disease resistance and superior bean quality. Within just 3 to 4 years, producers can engineer new coffee varieties that possess highly specific traits. Over time, several new coffee varietals, like the Sidra variety, have emerged on the market, showing very promising results. These new varieties often outperform their parent strains in multiple aspects, ultimately providing significant benefits to the producers.
How Grafting Works
Selection of Scion and Rootstock: The scion is the part of the plant that grows above ground, like leaves, flowers, or fruits. The rootstock is chosen for its robust root system and resistance to soil diseases or pests. Both need to be closely related species or varieties to ensure successful grafting.
Preparation: The scion and rootstock are cut to fit together tightly. This usually involves a diagonal or specific cut, like a cleft or whip graft, to maximise contact between the vascular tissues of the two parts.
Joining: The scion is inserted into the cut made on the rootstock. It’s crucial to align the cambium layers (the part of the plant that generates new growth) of both the scion and rootstock to ensure successful integration.
Securing: The graft is secured tightly using grafting tape, wax, or a similar substance to hold the parts together and prevent drying out.
Healing: If successful, the scion and rootstock will grow together over time, functioning as a single plant. This process is known as “healing” or “callusing.”
The benefits of grafting
Disease Resistance: Grafting can introduce disease resistance to high-quality coffee varieties that are susceptible to certain diseases. For instance, a high-yielding Arabica variety can be grafted onto a Robusta coffee plant rootstock, known for its resistance to root diseases and pests, like nematodes.
Enhancing Vigour: Grafting can combine the robust root system of one coffee plant with the superior bean quality of another, potentially increasing overall productivity and resilience.
Propagation of Superior Cultivars: Some high-quality coffee cultivars don’t produce true-to-type plants from seed. Grafting ensures these superior cultivars’ propagation.
Adaptation to Soil Conditions: Coffee plants grafted onto specific rootstocks can better adapt to various soil conditions, including high salinity or low fertility, thereby expanding the areas where coffee can be successfully grown.
Grafting is a sophisticated cultivation method in coffee agriculture that can significantly improve the yield, quality, and disease resistance of coffee plants. By carefully selecting and pairing rootstocks and scions, coffee farmers can create plants adapted to their specific growing conditions and challenges.
The Zest Mission
At Zest, we embrace these types of innovations and strive to support producers’ initiatives. We believe that by backing this type of research and development, we can make it more financially sustainable for producers to push boundaries in quality, yield, and resistance to an ever-changing environment.
We currently have two coffees from Colombian producer Cafe Granja La Esperanza which were created via the grafting technique – the Mandela (a hybrid of Caturra, Timor, and Ethiopian landrace), and CGLE-17, a hybrid of Caturra and Gesha.
These coffees are absolutely delicious, and can try them for yourself via the link below.