Coffee plant propagation
For propagation of Arabica coffee, ripe red cherries are collected, pulped, and the mucilage is removed by fermentation. The freshly picked coffee seeds (typically referred to as beans) can either be planted immediately or dried for later use. Coffee drying takes place on wire mesh trays in the shade. Correctly storing coffee beans is essential for a longer seed life. Dried coffee seeds can be used up to a year or more if properly stored.
Coffee bean germination process
There are two basic methods for the germination of seeds. In one method, coffee seeds are pregerminated by spreading on a sand bed and covering with moist burlap bag sacks or straw. The seeds are watched closely and removed as soon as radicals emerge. An alternative method of germinating coffee beans is to mix the seeds with moist vermiculite or expanded polystyrene and keep in the polythene bag. Coffee seedlings are grown in nursery beds or polybags and are planted in the coffee fields when they reach 20-40 cm.
Growing coffee seeds in nursery beds
Once pregerminated, the coffee seedlings are planted in nursery beds containing soil consisting of well rotted cattle manure (10-20 liters per meter) and phosphate fertilizer (100 g per meter). Nursery beds should be built to be 1 meter wide and 50 cm deep and seedlings are spaced between 12-15 cm apart (for 20 cm tall plants) or 20 cm apart (for 30-40 cm tall plants) (Mitchell, 47). The nursery beds are shaded 50 percent for the first couple of months. Shading is reduced slowly and completely removed the last two months before planting coffee seedlings.
Growing coffee seeds in polybags
Polybags, made of black diothene (200-gauge), are commonly used and filled with a mixture of topsoil, well rotted cattle manure, course sand, gravel, coffee pulp, and coffee husks. A ratio of three parts top soil to one part course sand and one part cattle manure is often used. A top dressing of nitrogen is applied by applying 20 g urea in 5.0 L of water per meter of bed.
Best climate conditions for growing coffee
For growing Arabica coffee beans, there are two optimal growing climates:
1. The subtropical regions, at high altitudes of 16-24°. Rainy and dry seasons must be well defined, and altitude must be between 1800-3600 feet. These conditions result in one coffee growing season and one maturation season, usually in the coldest part of autumn. Mexico, Jamaica, the S. Paulo and Minas Gerais regions in Brazil, and Zimbabwe are examples of areas with these climate conditions.
2. The equatorial regions at latitudes lower than 10° and altitudes of 3600-6300 feet. Frequent rainfall causes almost continuous flowering, which results in two coffee harvesting seasons. The period of highest rainfall determines the main harvesting period, while the period of least rainfall determines the second harvest season. Because rainfall is too frequent for patio drying to occur, artificial drying with mechanical dryers is performed in this type of coffee growing environment. Examples of countries that have this climate are Kenya, Colombia, and Ethiopia.
Robusta coffee is grown at much lower altitudes (sea level-3000 feet) in an area 10° North and South of the equator. It is much more tolerant to warm conditions than Arabica coffee.
Mitchell, H. W. 1988. Cultivation and Harvesting of the Arabica Coffee Tree. Coffee: Agronomy. Ed. R.J. Clarke. New York: Elsevier Applied Science.
Source: CoffeeResearch.org [www.CoffeeResearch.org]