True pine trees don’t do well as houseplants, though some potted pines can be brought indoors for several weeks each year to serve as holiday decorations. Yet at least one member of an ancient family of tropical evergreen conifers does fine indoors, assuming sufficient light and humidity. The graceful Norfolk Island pine, or Araucaria heterophylla, grew worldwide during the Jurassic and Cretaceous periods, when dinosaurs ruled the earth. In nature these pine-like trees grow to 220 feet tall with trunks 10 feet across. When thriving as houseplants, Norfolk Island pines grow 6 to 9 inches per year.
Choose an indoor location that mimics natural growing conditions, starting with light. Provide bright but indirect light, such as a north-facing window, making sure that sunlight doesn’t touch the plant. Rotate the tree a quarter-turn each week, to keep it growing straight, if light comes from one direction only.
Provide a “cool climate,” with daytime temperature of 68 to 72 degrees Fahrenheit and 50 to 55 degrees at night, though Norfolk Island pines can tolerate a low of 45 and a high of 85 degrees. Avoid placing these trees near a heating vent or other heat source.
Plant your Norfolk Island pine in a container with multiple drainage holes, in light houseplant soil that provides good drainage. These pines require less water than many houseplants, and don’t like “wet feet;” in nature, they thrive in very sandy soil.
Provide moist air for Norfolk Island pines, which do best at about 50 percent humidity. Fill the drain tray with rocks or pebbles and place the tree’s pot on top of the rocks. Add water to the tray, to just below the rocks’ tops. Alternatively, provide a room humidifier.
Mist Norfolk Island pines with distilled water also, to support high humidity but also to discourage the spider mite, a common houseplant pest. Start by misting daily. As the outdoor temperatures go down--and the heat comes on--increase misting to twice daily.
Water your tree only as needed, when the top inch of potting soil is dry. Pick a time when “humidity water” in the drain tray is at a low level. Use sufficient water so some excess drains out of the pot.
Feed Norfolk Island pines during the growing season with soluble houseplant food mixed with water at the suggested dilution. Fertilize new or recently repotted plants once every four to six months, and established plants once every three or four months. Don’t fertilize during the winter when plants rest.