Indoor Australian Tree Fern

The Australian tree fern (Sphaeropteris cooperi) can give any indoor setting a tropical appearance. This tree fern can easily grow 20 feet in height with a 15-foot spread. The fern has a single trunk that has a unique furry appearance. The evergreen foliage is lacy and measures over a foot in length. The tree is only capable of living indoors or outside in tropical conditions in Zone 10. It flourishes when grown in a container as a deck or patio plant and moved indoors during cool weather.

Light Requirements

The Australian tree fern flourishes in shady conditions. Place it in a window where direct sunlight will not reach the plant during the height of the day. Filtered light situations are ideal for indoor growth. Direct sunlight from a south-facing window can easily burn the tree's foliage when focused through the window glass. The tree is often set outside in the shade beside a pool, patio, deck or pond during the height of summer when there is no danger of frost. It benefits from the added air circulation it receives outside.

Soil Requirements

The tree enjoys well-draining, sandy soil conditions that are slightly acidic. A high quality potting soil is normally ideal for the Australian tree fern's requirements.

Humidity

The Australian tree fern requires a humid environment to flourish. When the tree suffers from lack of humidity the fronds will often dry and shrivel at the ends. Spray the plant daily to add moisture to its indoor environment. Place the entire pot in a saucer filled with pebbles and rocks. The water evaporates from around the pebbles and forms humidity around the tree, without allowing the roots to sit in water. Adding a humidifier to the room in dry wintertime conditions is also ideal for the plant's health.

Watering Needs

Keep the soil moist to the touch but not overly damp. The Australian tree fern enjoys moist soil conditions and will suffer if it becomes too dry. The tree enjoys being taken outdoors in the height of summer and hosed off.

Fertilizing During Growth

Fertilize the Australian tree fern once a month in the spring and summer, using a diluted fish emulsion. The substance is available at most garden centers. Follow the instructions on the label for application. The fertilizer will not burn the tree's root system when the plant is grown indoors in a container, as commercial chemical fertilizers often do.