Coffee beans grow on an attractive little plant with glossy green leaves and a compact growth habit. 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.
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. The best time to start a coffee plant is in the early spring. (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.
|Botanical Name||Coffea arabica|
|Common Name||Coffee plant, Arabian coffee|
|Plant Type||Evergreen perennial|
|Mature Size||6 to 15 feet tall and wide|
|Sun Exposure||Bright, indirect light|
|Soil Type||Rich and moist|
|Soil pH||Acidic to neutral|
|Hardiness Zones||9 to 11|
|Native Area||Ethiopia, tropical Africa|
How to Grow Coffee Plants
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 its 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. Coffee plants can grow in soil with a pH range of 4 to 7 but 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 Fahrenheit and a nighttime temperature between 65 and 70 degrees Fahrenheit. 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 rain and fog. A 50% or higher humidity level 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.
Potting and Repotting
Repot your coffee plant every spring, gradually stepping up the pot size. Make sure the container has several drainage holes. If you want, you can prune the plant to the desired size, slightly restrict its pot size, and root prune to keep its growth manageable.
Propagating Coffee Plants
To propagate a coffee plant, you must use seed from an existing plant or purchase fresh seed.
Coffee plants can also be propagated from cuttings or air layers (a somewhat involved technique where you root branches still attached to the parent plant). The best time to take a cutting is in the early summer. Select a straight shoot that's about 8 to 10 inches long and remove all but a pair of upper leaves. Then, plant the cutting in a small pot of soilless potting mix, and keep the soil slightly moist. When you can gently tug on the plant and feel resistance, you'll know roots have formed.
Toxicity of Coffee Plants
All parts of the coffee plant are toxic to cats, dogs, horses, birds, and other animals. Likewise, all plant parts except for the mature fruit (the coffee bean) are toxic to humans.
Symptoms of Poisoning
Common symptoms of coffee plant poisoning for both humans and animals include vomiting, diarrhea, nausea, and lack of appetite. More severe toxicity can cause an irregular heart rate, seizures, and occasionally death.
Coffee plants will sometimes suffer from infestations of mealybugs, aphids, and mites. Signs of infestation include tiny webs, 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. Start with the least toxic treatment option first, only progressing to more serious chemicals if your initial efforts fail.
Varieties of Coffee Plants
There are more than 120 species of plants in the Coffea genus with Coffea arabica making up the majority of global coffee production. Some plants in this genus include:
- Coffea arabica 'Nana': This is a dwarf variety that only grows 12 inches tall making it ideal to cultivate indoors.
- Coffea canephora: Commonly known as robusta coffee, this species comes from sub-Saharan Africa. Its plants are robust; however, the coffee beans are less favored because they tend to have a stronger, harsher taste than arabica beans.
- Coffea liberica: This species is native to central and western Africa, first discovered in Liberia. It produces large fruits that have a higher caffeine content than arabica beans but lower than robusta beans.
An unrelated species, Psychotria nervosa is a Flordia native that known as wild coffee and is grown as a landscape plant in southern Florida.