Potting media used for Norfolk Island Pine must be supportive of trunks and help make up for the limited root systems of these trees. Mixes with slightly more aeration should be used for seedling trees, but care must be taken not to transplant them before they start leaning because of weak root systems. Norfolk Island Pine will tolerate a wide temperature range. Temperatures below 25 F can cause severe freeze damage, especially if accompanied by wind. Suggested production temperatures are 60 to 90 F for seedlings and liners and 45 to 90 F for potted trees.
Light levels can also have a tremendous effect on growth and appearance.
Trees grown in full sun will be compact, have a strong trunk and a light to medium green color, whereas shade grown plants have a more open appearance, a weaker trunk and dark green foliage. Producers usually stake trees in 3 gallon pot sizes and larger because they do not form a strong root system and plants often lean, causing unsightly bending of the growing terminal. Fertilization regimes required depend on light intensity utilized. Symptoms - Trunks are loose in pots causing trees to lean and develop bent growing points. Control - Moderately tight potting media, proper fertilization, adequate light intensity and protection from wind will all contribute toward prevention of leaning trunks.