The olive tree, or Olea europaea, is a species of small tree native to the eastern Mediterranean region. Growers in this area cultivate olives trees commercially for the oil in the olive fruit. Olive trees do not grow true from seed, so olive trees propagated in this manner may produce smaller olives than the cultivated varieties. Olive trees require warm weather throughout the year, so gardeners in the United States typically grow them in containers.
Obtain olive seeds from a commercial seed provider. Raw, unprocessed olives may also contain viable seeds.
Mix a rich potting soil for olive trees that provides good drainage. A good soil mixture consists of 2 parts loam, 2 parts peat moss and 1 part sand. Fill a planting tray 3 inches deep with the potting soil.
Place the seeds in the potting soil, at a depth of 1/4 to 1/2 inch and move the planting tray to a sunny location. Water the soil regularly to keep it moist but not wet. Spray the soil with fine mist to create a humid environment for the olive trees. The seeds should germinate in several weeks.
Transplant the olive seedlings to individual pots once they grow two pairs of leaves and move the plants outside when the temperature stays above 8.89 degrees Celsius. Water the seedlings twice each week during the growing season to keep the soil moist. Apply a balanced fertiliser each month according to the manufacturer's instructions.
Move the plants inside before the temperature drops below 8.89 degrees Celsius. Reduce the watering schedule to twice a month during the winter.
Transplant the olive trees to larger containers as they grow. A mature olive tree can withstand temperatures as low as 0-9.444 degrees Celsius, so it can grow outside in U.S. Department of Agriculture of hardiness zone 9 and higher.