Photo: Coffee plantation, Kauaʻi, Hawaii (Wikimedia)

Coffee trees must be grown at certain elevations, with Robusta typically at 800m and below and Arabica at higher elevations, in certain countries up to over 2,000m. The best coffee is grown in deep, well-draining sandy loam or volcanic red earth with a slightly acidic pH of 5.3-6.0. Heavy clay, loam, or sand is unsuitable because of poor aeration, or because the soil will dry rapidly. Erosion can also be an issue.  (Assefa et al.; Bullough)

 

Much of the world’s coffee is grown in areas where tectonic activity has formed mountains and mountain ranges or chains, including the extinct Mount Kenya in Africa, the active Apaneca-Ilamatepec range in El Salvador, the Andes in South America, and even the islands of Hawaii. (Hoffmann)  Along with the tropical climates and high altitudes coffee needs to grow, these mountains provide fertile, nutrient rich soils the coffee trees can thrive in called Andisols.  Formed in volcanic ash, these soils can include elements such as phosphorus, nitrogen, potassium, calcium, zinc and boron which are all used by the plant to help it produce coffee. (Bullough)

 

Even though coffee trees are growing in young, fertile volcanic soils, intense coffee production continues to deplete nutrients, leading certain farmers to use chemical fertilizers as well as herbicides and pesticides. Many of these are not only bad for the environment but may also further deplete soils of what the trees really need. (Cerdán et al.)  Another issue faced by farmers is the danger of the proximity of farms to active volcanoes – a huge risk in order to grow in some of the best suited soils for achieving great coffee quality. (Hoffmann)

 

 

Photo: Coffee and banana agroforestry in Uganda by James Anderson, World Resources Institute.

While over 120 different species of coffee trees (coffea) have been identified, the two most commonly used in the production of coffee are Arabica (Coffea arabica) and Robusta (Coffea canephora).  Robusta is more resistant to disease, grown at lower altitudes, warmer temperatures, and produces higher yields; however, it generally makes coffee of lesser quality.  (Hoffmann)  The majority of coffee produced uses Arabica which originated in Ethiopia and is grown at higher altitudes.  It gained popularity as a drink in Yemen around 1500 and has spread throughout the world since, mainly due to trade and colonization. (Topik)  Coffee is grown in tropical climates between the Tropic of Capricorn and Tropic of Cancer in Africa, Asia, Central, and South America.

 

Coffee trees can grow up to 8 meters high but are usually pruned to a shrub size more suitable for harvesting. (Kew)  The fruit of the coffee tree is called a cherry, with two or sometimes one coffee seed, or bean growing inside.  After a period of rain that allows trees to begin flowering, most trees then take up to 9 months for these cherries to ripen.  Different varieties of Arabica include Bourbon, Pacamara, Typica, and SL-28 and the colors of ripe cherries can range from yellow to dark red-purple depending on the variety.  (Hoffman)

 

 

 

 

 

 

 

 

 

Coffee does well when grown as traditional in shade, well draining and nutrient rich soils (usually volcanic), and at altitudes of 950–2000+ m. Climate change and other effects such as diseases and pests -coffee leaf rust and the coffee cherry borer- threaten coffee production and quality.  (Kew)  Most trees are grown on small farms rather than large estates and there is increased effort in agroforestry, biodynamic farming, and farmer education to help produce healthier trees.