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 will have to take that pruning to another level and keep the plant truly small. Note that you cannot grow coffee from the beans you buy in a store; those have been treated and roasted and will not sprout.
- Botanical name: Coffea arabica
- Common name: Coffee plant
- Plant type: Evergreen perennial
- Mature size: 6 feet tall and 3 feet wide
- Sun exposure: Bright, indirect light
- Soil type: Rich and moist
- Soil pH: Acidic to neutral
- Bloom time: Spring
- Flower color: White
- Hardiness zones: 9 to 11
- Native area: Tropical Africa and tropical Asia
How to Grow Coffee Plants
To best grow C. Arabica plants, mimic 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 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.
A rich, peat-based potting soil with excellent drainage is beneficial. Coffee plants do not like limey soils, so if your plant is not thriving, add some organic matter like peat. Coffee plants can grow in soil that has a pH of 4 to 7. The ideal soil pH range is closer to 6 to 6.5.
These plants are water lovers and require both regular and ample water.
Temperature and Humidity
Since these plants naturally grow on the sides of tropical mountains, they thrive in highly humid conditions. They usually get a lot of rain and plenty of fog. Their optimal average temperature range is between and 64 and 70 degrees Fahrenheit. Hotter temperatures may accelerate growth, but that is not something you want when growing plants for beans. The fruits should ripen at a slower, steadier pace.
Feed with a weak liquid fertilizer throughout the growing season. Cut fertilizer back to once a month or so in the winter.
Potting and Repotting
Repot 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.
Keep an eye out for bugs, too. 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.
Propagating Coffee Plants
To propagate a coffee plant, you will have to buy a seedling (they are sometimes available as novelties) or get fresh seed. Coffee plants can also be propagated from 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 which eventually become the coffee beans you use for the coffee drink.
Toxicity of Coffee Plants
All parts of the coffee plant, with the exception of the mature fruit (the coffee bean), are toxic to humans, cats, and dogs. Ingestion of these plants may cause vomiting or diarrhea.
Varieties of Coffee Plant
There are more than 120 species of plants in the genus. C. arabica, accounting for about 60 to 80 percent of all the consumed coffee in the world. Another popular bean comes from the C. canephora plant, which is also known as Coffea robusta. This species comes from sub-Saharan Africa. Its plants are more robust, however, the coffee beans are less favored because they tend to have a stronger, harsher taste. Arabica beans tend to be sweeter with undertones of sugar, berries, and fruit.
One unrelated species, Psychotria nervosa, is known as wild coffee and grown as a landscape plant in southern Florida.