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.

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 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.

Light

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.

Soil

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.

Water

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.1

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 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.

Fertilizer

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.

Is Coffee Plant Toxic?

All parts of the coffee plant are considered 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. Official listings of toxic plants categorize it as a minor toxic—a category normally reserved for plants causing non-fatal intestinal discomfort.2

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 in animals. Horses grazing on outdoor plants are particularly susceptible. Human deaths are extremely rare (perhaps nonexistent), but you should still call a poison control agency if any plant parts other than the dried and ground-up coffee beans are consumed. Remember that the attractive red berries are NOT edible, only the coffee beans inside.2

Coffee Plant Varieties

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 known as wild coffee and is grown as a landscape plant in southern Florida.

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.

Harvesting Coffee Beans

When grown indoors, coffee plants are normally grown for ornament rather than production, but as a novelty, you can harvest the berries of your coffee plant once the plant has matured for three to five years and is producing fruit.

When the fruits ("cherries") of your plant have ripened to red and are slightly soft to the touch, pick them off the plant by hand. Separate the inner coffee beans from the fruit by pulping the cherries in a bowl of water.

After separating the inner beans, lay them out on wire mesh and dry them until the skins can be flaked off easily. This can take several days or even weeks. The dried beans can now be ground in a coffee mill, just as you do with beans purchased in the store.

Common Pests/ Diseases

Coffee plants grown indoors will sometimes suffer from infestations of mealybugs, aphids, and mites.1 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.