Coffee (Coffea arabica) is a small evergreen tree with glossy leaves that thrives in cool, misty locations in Hawaii. Most of Hawaii's coffee is grown in the "Kona coffee belt," which ranges from 700 to 2,000 feet in elevation, and is only 2 miles wide and 20 miles long. Coffee can also be successfully grown in lower, windward locations, provided there is ample moisture. These trees grow and produce best on deep, rich, well-drained soils. Harvests can be significantly increased with timely fertilization, ample irrigation and regular pruning to facilitate air circulation.
Prepare planting holes with rich, well-draining soil, and add organic compost, mixing well with the shovel. Space your coffee trees at least 8 to 10 feet apart for optimal growth, especially on very porous soils or in cloudy areas. Select a sunny location, sheltered from harsh winds.
Place each 1- to 2-foot-tall coffee seedling in its hole at a 45-degree angle to encourage new vertical growth to form. Firm the soil gently and water thoroughly. Keep the soil moist until the plants are well-established.
Apply a 4- to 6-inch layer of organic mulch, such as composted macadamia nut hulls, around the base of each tree, avoiding the area right next to the trunk. Add more mulch several times a year, or as necessary to maintain a thick layer.
Feed your coffee plants four to five times a year by applying composted manure or a balanced fertilizer. Use fertilizers with higher potassium content for young volcanic soils. On very porous volcanic soils, feed more frequent lighter applications to offset leeching.
Harvest ripe cherries from August through December. Coffee cherries are deep red when ripe, and must be carefully monitored and harvested by hand, since the fruit on each plant ripens over a period of weeks, rather than all at once.
Prune sparingly with pruning shears or loppers just after harvest, from December through February, since coffee berries form on 1-year-old wood. Make all pruning cuts with a diagonal slant, and paint immediately with a protective pruning sealant to prevent rot. Prune away any suckers and dead wood, but leave as many healthy vertical shoots as possible.