Coffee News: from Seed to Cup

A Guide to Grafting Coffee Plants

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Why do some producers graft coffee trees? The process can be tricky and usually costs more than planting standard plants. 

But there can be advantages to growing grafted coffee, such as pest-resistance. Let’s learn a little more about what grafting is and the advantages and disadvantages of grafting coffee trees.

Lee este artículo en español Cómo Hacer Injertos en Las Plantas de Café

Producer Gilberto Benitez shows a grafted coffee tree at his farm in El Salvador. Credit: Maren Barbee via Flickr, CC BY 2.0

What Is Grafting & Why Do It?

Grafting is the joining together of two plants, which is done for a number of reasons.

Ray Taggart is Farm Manager at Heavenly Hawaiian, a coffee farm in Kona, Hawaii. He tells me that in coffee plants grafting is used to “take the best attributes of two coffee cultivars and combine them to get all the benefits of both in a single plant.”

To do this, a producer takes the rootstock of one tree and the scion of another and attaches them.

The rootstock is the lower part of a plant, made up of the roots and some stem. It provides anchorage and support to the upper parts of the plant.

The scion is the main component of the plant shoot when the plant is fully developed. It usually consists of the primary stem and branches. The scion determines the characteristics of the plant.

You may also like A Producer’s Guide to Pruning & Stumping Coffee Trees

A coffee plant at Finca La Fany in El Salvador. Credit: Julio Guevara

Ray says that in his experience, grafting usually pairs “pest and drought resistant rootstock with the flavorful and productive top or scion.” He tells me that “typically, Arabica is used for the scion since it has a more mellow flavor and good acidity, and Liberica has been the favored rootstock for its vigorous growth and resistance, although other cultivars have also been used.

Grafting can give you the edge you need for production and help prevent crop loss or plant death. In farming, you need every advantage you can get to stay in business, let alone stay competitive.”

Learn more in Origin Insight Video: Why & How Do Coffee Farmers Graft?

Coffee trees at Finca La Fany in El Salvador. Credit: Julio Guevara

Advantages of Growing Grafted Coffee Plants

The main goal of grafting coffee plants is to create a crop with the best attributes of two plants in one. For example, a grafted plant might offer the flavorful cherries and good yield of one variety, as well as the disease resistance of a second. Grafting can also provides anchorage and support to fragile or damaged trees.

Ray says, “For coffee specifically, we are mostly looking for the vigorous growth rate of the roots. The roots of the Liberica cultivar grow much faster than the Arabica cultivar. They can outgrow the damaging effects of a nematode that lives in the soil. The nematode eats the roots of the trees and Liberica grows so fast that the trees are not affected by the damage.”

So, grafting can reduce the risk of losing a coffee harvest to pests, and the need for pesticides.

A coffee tree affected by the Kona coffee root knot nematode. Credit: Scot Nelson

Cesar Echeverry is Farm Manager at Supracafé Farms. He says that “grafting is used mainly to propagate and allow the growth of varieties of commercial value in conditions that are unfavorable.”

In short, grafting allows producers with less-than-ideal conditions to grow varieties that would otherwise be poorly suited to their farm.

Ray says, “Liberica also is more drought and heat resistant, which can help trees survive climate changes that will happen from season to season. Overall, grafted plants are healthier, hardier, and more resistant to anything that mother nature can throw at them. Farmers can use the help anywhere we can get it.”

A coffee producer walks through his farm in El Salvador. Credit: Fernando Pocasangre

Downsides to Grafting Coffee Plants

The main downside of grafting is that it takes more time and labor than planting conventional coffee trees, as well as greater investment at the start. This means that not all farmers have the resources to use grafted plants.

Ray says, “Grafting is not an easy process to master and can be slow. It is very detail oriented. You will not be 100% successful even if you are an expert. You have to prepare at least 20% more plants than you need and many farmers will plant upwards of 40 to 50% more just to be safe.

“It also requires two plants for each single grafted coffee tree that you need. If a farmer needs 1,000 trees, they would typically plant around 3,000 seeds. Some seeds will not even germinate. Some plants will be weak or have defects and they will have to be discarded. The plants that make it to grafting will not all survive the process.”

But in the long term, grafting can be cost effective for producers. Ray says, “Even though there is an initial cost to get grafted trees, the overall cost impact is quickly canceled out by increased production and resistance to environmental factors like drought or heat stress and soil-borne pests.”

A coffee plant at Finca La Fany in El Salvador. Credit: Julio Guevara

How to Graft a Coffee Plant

Grafting is not something that farmers should invest in without instruction and practice. There is a great risk of plants failing if the method isn’t done exactly right. 

Seemingly successful grafts may fail for many reasons, including that the rootstock and the scion may not be compatible, grafting was done at the wrong time, or one or both of the rootstock and scion were not healthy. The cut plants are also vulnerable to pests and diseases if they aren’t properly joined.

Cesar says, “Specific knowledge and experience is required, as these are tasks of utmost precision.”

Young coffee plants at Finca La Fany in El Salvador. Credit: Julio Guevara

The process begins with germinating coffee in flats. Ray tells me that “due to the way the seeds and baby plants develop, we have to plan the germination so that the trees will be the same size when we are ready to graft. This means that the Liberica is planted first and the Arabica will be planted a few months later. It takes about 50 days for the seeds to germinate, so there is a lot of waiting and watching.”

Once the seeds have germinated and grown a few inches, the grafting process can be started. Ray says, “I have found grafting young trees is the most successful, but you can’t start too early either. You then select a tree from each variety that has the same thickness to the central stem.”

Ripe coffee cherries on a tree at Mapache Coffee in El Salvador. Credit: Fernando Pocasangre

The farmer uses sanitized equipment to separate the top of the root and the rootstock from the scion. Then, they use grafting clips or wax-based grafting tape to join the two freshly cut ends together, making sure they line up exactly. The clip or wrap will hold them in place while the two ends knit together into one plant.

Cesar tells me that it’s important to keep young grafted plants in the right conditions while they join together. He says, “The temperature and humidity of the graft must be controlled to favor the union. [The producer must be aware of] hydration, evaluation, and monitoring of the viability and health of the grafted plant.”

Ray says, “After the graft has healed, on many plants it is almost imperceptible. If you came back 100 years later and genetically tested, the tree roots would be 100% Liberica and the top 100% Arabica.”

 A producer grafts a coffee plant. Credit: Maren Barbee via Flickr, CC BY 2.0

Grafting plants takes expert knowledge and investment in labor and resources, but with careful planning it can be a useful tool for producers.

Successfully grafted plants can provide better resistance to pest and diseases and allow you to grow popular varieties in less-than-ideal conditions. These factors can help you reduce the cost of pesticides and fertilizers, and may provide you with better quality crops and higher prices.

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Written by Miguel A. Hernández Zambrano. Interview with Cesar Echeverry translated from Spanish. Feature photo: Detail of coffee berries of a grafted plant in El Salvador. Feature photo credit: Credit: Maren Barbee via Flickr, CC BY 2.0

Please note: Before implementing the advice in this article, we advise also consulting with a local technical expert, since differences in climate, soil type, varieties, processing methods, and more can affect the best practices for production and processing.

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