Coffee beans grow on an attractive little plant with glossy green leaves and a compact growth habit. In their native habitat, they like to grow into medium-sized trees, but the plants are regularly pruned to a more manageable size by coffee plantation growers.
If you want to grow a coffee tree inside, you'll have to take that pruning to another level and keep the plant truly small. As a last note, you cannot grow coffee from the beans you buy in a store. Those have been treated and roasted and will not sprout. Instead, you'll have to either buy a seedling (and they are sometimes available as novelties) or get fresh seed.
Growing Conditions for Coffee Trees
Coffee trees prefer dappled sunlight or, in weaker latitudes, full sunlight. They are actually understory, or marginal plants so do not like a lot of direct, harsh sunlight. Plants that are exposed to too much light will develop leaf-browning.
These plants are water lovers and require both regular and ample water and high humidity. In their preferred growth habit, they grow on the sides of tropical mountains, where they get lots of rain and plenty of fog. A rich, peat-based potting soil with excellent drainage is beneficial.
Feed with a weak liquid fertilizer throughout the growing season. Cut fertilizer back to once a month or so in the winter.
Propagation of Coffee Trees
Coffee plants can be propagated from seeds or by cuttings or air layers (a somewhat involved technique used by professional programs). The coffee tree will flower in the spring with small white flowers and then bear half-inch berries that gradually darken from green into blackish pods.
Each of these fruits contains two seeds; these seeds are actually the coffee beans that are used to make the drink.
Repotting Coffee Plants
Re-pot your coffee plant every spring, gradually stepping up the pot size. As with many trees, to keep the plant manageable, prune it to the desired size, slightly restrict its pot size, and root prune for best results.
Coffee Plant Varieties
There are about 40 species of plants in the genus. One unrelated species, Psychotria nervosa, is known as wild coffee and grown as a landscape plant in southern Florida.
The true coffee species is C. Arabica, grown for its beans. This plant is a woody shrub native to tropical east Africa, where it grows at relatively higher elevations. The C. Arabica plant has been naturalized through the tropical world and is one of the world's most important plants.
Grower's Tips for Arabica Plants
To best grow C. Arabica plants, do your best to provide the conditions found on a tropical, mid-elevation mountainside: lots of water with good drainage, high humidity, relatively cool temperatures, and rich, slightly acidic soil.
Coffee plants do not like limey soils, so if your plant isn't thriving, add some organic matter like peat.
Coffee will sometimes suffer from infestations of mealybugs, aphids, and mites. Signs of infestation include tiny webs on plants, clumps of white "powdery" residue, or visible insects on the plant. Treat infestations as soon as possible to prevent them from spreading to the rest of your collection. As always, start with the least toxic treatment option first, only progressing to more serious chemicals if your initial efforts fail.