There are two varieties of coffee plants: robusta and arabica. Arabica coffee plants produce larger beans that are less bitter than robusta beans. Both types of coffee beans are very sensitive to a number of factors. Unless arabica bushes are grown under good conditions, the plants may not survive and they may not produce a good crop of high-quality beans.
Arabica coffee bushes will not tolerate freezing temperatures. Ideal temperatures for growing coffee are between 59 and 75 degrees F. Above 77 degrees F, the growth of arabica coffee plants slows. If the temperature reaches or exceeds 86 degrees F, the leaves and the plant may be damaged.
Because of the limited ranges in which arabica plants thrive, they generally grow at higher altitudes between the Tropic of Cancer and the Tropic of Capricorn. In more northern climates, winter temperatures at lower elevations drop too low for the plants. In lower elevations in the tropics, temperatures are too high for effective cultivation. Arabica coffee plants grow best at around 3,500 feet in the tropics.
Arabica plants grow well in a variety of soils, as long as they drain well. They do especially well in volcanic soils that drain well. Topsoils that are leached of nutrients will not support coffee, nor will areas with very hard sub-soil layers or solid rock below the surface. In heavy soils, such as primarily clay soils, or other soils where drainage is a problem, arabica plants may not do well and may, possibly, die.
Newly planted bushes need regular water until they become well established. Although the amount of water will vary, depending on rainfall levels, 2 to 3 inches twice a week should be sufficient. Once established, you can control vegetative growth of your coffee bush by increasing or decreasing water amounts. Reduce water and stop watering sometime between January and February. Begin watering in March or April to stimulate flower production that will result in fruit and their resultant beans.
Whether your arabica plant needs fertilizer and how much fertilizer it needs depends a lot on where you are growing your coffee plant. Arabica coffee plants that are grown in the shade need less fertilizer and water than bushes grown in full sun. In some cases, in situations where you do not want to fertilize, planting the plants in the shade can reduce the plant's flowering, and thus reduce or eliminate the need for fertilizer.
Growing Coffee in the U.S.
The only part of the United States that has the combination of being in the tropics and having suitable soils, altitude and rainfall are certain islands in Hawaii. Kona is the best-known island. Coffee can sometimes grow outside in Florida, but Florida's high temperatures will not result in good growth and coffee production. In many cases, you can grow ornamental coffee arabica plants in pots.