Soil Requirements for an Indoor Norfolk Pine

Basic Soil Requirements

• Norfolk Island pine grows in clay, loamy and sandy soil consistencies and a range of pH levels. Regardless of consistency or pH, the plant prefers well-drained soil. Commercially available potting mixture works just fine for indoor Norfolk Island pines, or you can use a mixture of sterilized potting soil, peat moss and sand or perlite, amended with about 1 teaspoon of bone meal.

Soil Care

• Horticulturalist Colleen Wheeler of Grow Native nursery in Los Angeles, California, recommends applying a four-month, slow release fertilizer with a 15-15-15 NPK ratio to your Norfolk Island pine three times per year. Work about 0.4 ounces of fertilizer per 1 gallon of potting soil into the top 2 inches of soil or follow the application rates on the fertilizer's label. Alternatively, you can use a 15-15-15 water-soluble fertilizer diluted to 1 1/2 teaspoons per 1 gallon of water, giving the Norfolk Island pine a light watering twice per year during the growing season. Repot the plant in new soil once every three to four years.

Watering and Soil Drainage

• Feel the top of the indoor Norfolk Island pine's soil to determine when it needs water. If the top 1 inch of soil is dry to the touch, water the plant slowly and deeply. Use a pot with holes to encourage healthy drainage for your plant -- you've watered enough when a bit of water seeps through the pot's drainage holes. Although the Norfolk Island pine likes moist soil, don't allow the soil to stay waterlogged soil or let it sit in water -- poor soil drainage may lead to root rot.

Other Requirements

• Although the Norfolk Island pine is a fairly low-maintenance plant in regards to soil and other needs, it does require high humidity -- about 50 percent relative humidity is best. Use an indoor humidifier to meet the tree's needs in this department. Similarly, misting the leaves and soil twice daily helps provide humidity to this moisture-loving plant. This indoor tree flourishes in bright, indirect sunlight and indoor daytime temperatures of about 60 to 72 degrees Fahrenheit. With the right soil, environmental conditions and care, the Norfolk Island pine leads a long life and grows about 3 to 6 inches per year.