Coffee plants are one of the most widely cultivated plants in the world, and coffee beans, the seeds of the coffee plant, are one of the world's top agricultural products. Native to tropical and sub-tropical Africa, coffee plants require a particular climate to thrive. Frost will kill them, and sustained temperatures above 80 degrees F (27 degrees C) are too warm. For this reason, coffee plants are often grown in mountainous areas of the tropics. Providing water, soil, light, and fertilizer ensures success in growing a coffee plant indoors.
Certain things must be kept in mind when growing a coffee plant indoors. They require warm temperatures that average around 70 degrees F (21 degrees C), so typical home temperatures are very well suited for growing a coffee plant. Humidity can be a problem, however, as coffee plants prefer very humid conditions. For this reason, a humidity tray, humidifier or frequent misting may be necessary.
A humidity tray is a tray on which the potted plant sits that is often filled with pebbles and a shallow layer of water. The water must not reach the bottom of the pot itself as coffee plants do not do well when their roots are too wet or sit in standing water for extended periods. The water in the tray serves to create a microclimate of humid air around the plant. Frequent misting with a spray bottle will also benefit the plant and a room humidifier can also help.
Light is of course another consideration for growing a coffee plant. Coffee plants prefer bright, indirect light, so they should be situated near a window that gets a good amount of light or under a skylight. They are often grown commercially under the shade of larger trees, so the conditions near a brightly lit window are perfect.
Soil for growing a coffee plant should be loose, rich in organic material, and very well drained. It should not dry out too quickly, but should allow excess moisture to drain easily. A basic potting soil should be sufficient for growing a coffee plant, but be sure to place a layer of lava rock, terra cotta shards, or pebbles in the bottom of the pot before planting.
A coffee plant requires a good deal of water and should be watered frequently but not kept wet. Slightly less water is required during the winter. A basic houseplant fertilizer should be applied regularly every two to three weeks during spring, summer, and fall but less frequently in the winter. After three or four years, the plant may flower and if hand pollinated may produce berries which take several months to ripen to a rich red color. These berries contain seeds that are the well known coffee bean.