Avocado trees (persea americana) grow well in USDA zones 9, 10 and 11 -- zones with average winter temperatures that remain above 20 degrees Fahrenheit -- because they are tropical plants. They can reach heights of 40 feet as long as they are planted in a hot, sunny location. Grow an avocado tree from a sapling because it's much easier than starting with a pit. As long as you plant it in a good spot and keep it watered, avocados are relatively low maintenance plants. However, expect your avocado tree to take about 10 years to bear fruit.
Choose a planting spot that is protected from the sun because avocado trees do not have bark, making them prone to damage. Avocados traditionally grow in the shade of another tree or against the north-facing side of a building.
Dig a hole at least twice as wide as the avocado tree's root mass. Use the nursery plant pot as a guide. The hole should be as deep as the pot because avocados need to be planted at or above the surrounding soil. Use the sharp edge of the shovel to loosen the dirt on the sides and bottom of the hole. This will allow the roots to expand.
Pour water into the planting hole and let it drain. If it drains slowly, layer a few inches of soil on the bottom of the hole to boost the avocado tree up higher so it drains quicker.
Remove the avocado tree from the nursery container. Place it upright in the hole and fill in around it with an even mixture of compost, soil and sand. Press it down to remove air pockets and then water until moist.
Create a berm or mound around the base of the avocado tree to improve drainage. Make the soil about 4 inches high, cover it with water, then add 4 inches of compost.
Water the avocado tree enough so the soil is always moist. During the winter, water it less because avocados do not grow well in cold, damp soil.
Fertilize avocado trees after their first year in the ground. Buy a fertilizer with an even ratio of nitrogen-phosphorus-potassium and apply in the fall and winter.