How to Grow and Care For Arabica (Coffee Plant)
The coffee plant is an attractive little specimen with glossy green leaves and a compact growth habit. It makes a surprisingly good potted indoor plant. Native to Ethiopia, the coffee plant (Coffea arabica) will flower in the spring with small white flowers and then bear half-inch berries that gradually darken from green to blackish pods. Each of these fruits contains two seeds, which eventually become the coffee beans you use to brew coffee. Other than the seeds, it's important to know that all plant parts are toxic to both humans and animals.12
In their native habitat, coffee plants grow into medium-sized trees. But growers regularly prune the plants to be a more manageable size, especially when the plants are grown indoors. (Note that you can't grow coffee plants from the beans you buy in a store; those have been treated and roasted and will not sprout.) Even though coffee plants are vigorous growers, it will typically take a few years before your plant produces flowers and subsequent fruits. All parts of the plant are toxic to pets and humans—the beans are edible to humans.
Coffee Plant Care
The best environment in which to grow coffee plants is to mimic its natural conditions found on a tropical, mid-elevation mountainside: plenty of water with good drainage, high humidity, relatively cool temperatures, and rich, slightly acidic soil.
You can grow coffee plants outdoors if the conditions are similar to their natural environment. Indoors, coffee plants do best placed near a window but not in direct sunlight. Make sure to keep the plant away from drafts, such as those produced from air conditioning. Be prepared to water at least weekly to keep the soil moist.
Coffee plants prefer dappled sunlight or full sunlight in weaker latitudes. They are actually understory plants (existing under the forest canopy) and do not thrive in direct, harsh sunlight. Coffee plants that are exposed to too much direct sunlight will develop leaf browning.
Plant coffee plants in a rich, peat-based potting soil with excellent drainage. Coffee plants prefer acidic soil, so if your plant is not thriving add organic matter such as sphagnum peat moss to increase soil pH. The ideal pH range is closer to 6 to 6.5.
These plants are water lovers and require both regular and ample watering. The soil should stay evenly moist but not waterlogged. Never allow the soil to dry out completely.
Temperature and Humidity
The optimal average temperature range for coffee plants is a daytime temperature between 70 to 80 degrees and a nighttime temperature between 65 to 70 degrees. Higher (hotter) temperatures can accelerate growth, but higher temperatures are not ideal for growing plants for their beans. The fruits need to ripen at a slow, steady pace.
In addition, because these plants naturally grow on the sides of tropical mountains, they thrive in highly humid conditions which usually receive plenty of rain and fog. A humidity level of 50 percent or higher should suffice. If the air is too dry, the leaf edges might start to brown. Mist the plant daily to raise the humidity level.
Feed with a weak liquid fertilizer throughout the growing season every couple of weeks. Cut the fertilizer back to once a month or so in the winter.