By Michael Griffin, Coffee Research Institute
Growing a coffee plant at home is a rewarding experience that will help you learn and appreciate the work involved in producing coffee. It is a very easy plant to take care of and is a great conversation piece, especially during flowering or cherry development. Ideally you should start with a freshly picked coffee cherry, but unless you are in a producing country this will not be possible and you should skip to section 2.
Section 1. Harvesting and Preparing the Coffee Seeds.
Ripe cherries should be harvested and picked from trees with a high production and without any disease or other affliction. Pulp the cherry by hand, wash with water, and ferment in a small container until the pulp falls off. This can be determined simply by rubbing the bean in you hands during the fermentation process. Wash again with fresh water. Any coffee beans that float at any stage of washing should be discarded. The beans must then be dried to about 20% moisture content on mesh screen in open and dry air, but not in direct sunlight. After pulping a coffee will have between 60-70% moisture content so you can determine the appropriate stopping point simply by weighing the beans. Otherwise, you can bite the bean open to ensure that it is dry on the outside and slightly soft and moist on the inside. Alternatively, a pulped bean can be used immediately for planting and in some areas this is considered advantageous.
Section 2. Germination.
If coffee cherries are not readily available, green coffee can be purchased from a local supplier, but it is essential that the bean is of a recent crop and recent shipment. I would recommend ordering green coffee from Sweet Maria's and asking for the most recent crop. The potential for germination will continue for almost four months, but after this time the germination rate is several fold less and germination time is significantly longer. Fresh seeds should germinate in 2.5 months, but old seeds can take as long as 6 months. Coffee in pergamino is even better. If this is available plant the coffee face down in the pergamino.
It is advisable to pre-germinate the seeds. First soak the seeds in water for 24 hours. Then sow the seeds in damp sand or wet vermiculite in which the excess water has been drained. Otherwise, you can place the seeds between moist coffee sacks, which should be watered twice a day and drained well.
Once the seed germinates very carefully remove it from the sand, vermiculite, or burlap bags. Make a hole about 1.25 cm deep in a friable loam soil with a high humus content. Rotted manure, bone meal, and dried blood can also be added. If this type of soil is not readily available try a light weight and porous soil. Place the seed flat side down in the hole and sprinkle soil over the hole. Do not press the soil down firmly. Placing a 1/2 inch of mulched grass on top will help preserve moisture, but should be removed when the seed has fully germinated.
The seeds should be watered daily. Too much water or too little water will kill the seed. The soil should remain well drained, but moist at all times.
After germination the plant should either be left alone or carefully removed and planted in a soil with a low pH (acidic) and high nitrogen content. The soil should be porous. Therefore, course sand or basalt gravel dust can be added. Manure can also be added. A fertilizer that is appropriate for orchids can be used sparingly for the coffee plant to maintain mineral levels and a low pH.
Section 3. Care.
The plant thrives under artificial plant lighting indoors. The outside temperature in countries outside the Tropic belt is too volatile and too cold to allow the tree to develop. I recommend watering the tree twice per week in what I call a full watering and a half watering. In a half watering, I simply add some water to the soil and allow it to drain. In a full watering I add water, allow it to drain, and then add water with fertilizer and allow it to drain. The key is to keep the soil most, but well drained.
After two or three years flowering and possibly cherries can be expected, but do not expect high-quality coffee unless you are at a high altitude and are monitoring the conditions of the artificial microclimate carefully. For more details please see the rest of the agriculture section. In theory, it is feasible to grow a high-quality coffee at home under the right conditions.
To spur flowering wait until the beginning of winter and significantly reduce watering for 2-3 months. When Spring begins water the plant well, which should shock it into producing flowers. From this point forward water well and regularly. Arabica coffee is self-fertilizing so you will not need to worry about pollinating.
Once the cherries mature you can harvest, pulp, ferment, dry, roast, and drink the coffee.