I was first exposed to Norfolk Island pines in James Michener's South Pacific, where he described rows of the huge pine trees on, well, Norfolk Island. Later, I moved to a place where Norfolk grow easily and where they are called suicide trees because they have a tendency to fall onto houses. Indoors, however, Norfolks are pretty little pine trees with a lacy, delicate appearance. They are, in fact, not even pine trees at all, but belong to a different plant family.
In the nursery trade, you're most likely to see Norfolks sold as mini-Christmas trees throughout the Christian world. They are frequently decorated with ribbons or ornaments and sold as specimens and easiest to find in the fall. If you're not interested in a Norfolk as a stand-in Christmas tree, they make pretty foliage plants and are usually kept below about three feet tall in smaller containers.
Light: They prefer full sun and tend to stretch out in dimmer conditions (see below). Give your plant the best light possible, or alternate between full sun and short periods in dimmer conditions.
Water: They are somewhat drought-tolerant, so they are a bit more forgiving where water is concerned, and it's advisable to let the soil dry out slightly between waterings.
Soil: These are acid-loving plants, with a preferred pH of about 5.5 or even 4.5. A peat-based mixture is perfect for them as the mix will gradually acidify as the peat breaks down.
Fertilizer: Feed with a weak liquid fertilizer throughout the growing season, although you may have to suspend fertilizing in low-light periods.
The Norfolk Island pine is a gymnosperm, meaning that a single plant contains male and female reproductive organs. Virtually all Norfolk Island pines are grown from seeds, which are usually imported from the Pacific region.
Most home growers will never bother with seeds or propagation.
Young Norfolk Island pines are not very fast growers, so it might be possible to repot every other year instead of every year. As the plant matures, it will begin to grow faster. Repot in the springtime, and if your plant has attained a larger size, make sure to use a pot with plenty of heavy material in the mix, such as potting sand, to provide enough weight to keep the plant upright.
There is only one variety on the market: the Araucaria heterophylla. This plant does not have cultivars or named varieties. A few other species from this family sometimes show up in the trade, mislabeled as the original plant. These include A. columnaris, A. araucana, and A. bidwillii. It's unlikely you'll see these, but the cultural requirements are similar just in case.
Norfolk Island pines—especially younger trees—have notoriously weak root systems, which is how they earned the name "suicide tree." To strengthen their roots, make sure you're supplying regular fertilizer and don't hesitate to stake your tree up if it needs it. Although they are full-sun plants whenever possible, they can also handle relatively long periods (months at a time) in dimmer conditions.
Thus, you can keep your plant inside during the winter, and then move it to a sunny spot outside when the summer comes around. If your plant begins to stretch while growing inside, the odds are that the combination of low light and heavy fertilizer is causing leggy growth. In that case, cut back on the fertilizer until the plant has more access to sunlight. Norfolk Island Pines are vulnerable to pests including aphids, mealybugs, scale, and white fly. If possible, identify the infestation as early as possible and treat with the leave toxic option.