Avocados, also called alligator pears, are fruits native to southern Mexico. Avocado trees (Persea spp.) grow best in warmer regions with mild winters, but some varieties tolerate cold better than others. Although the West Indian avocado varieties cannot tolerate freezing temperatures, and the Guatemalan types are hardy down to only 26 to 30 degrees F, the Mexican avocado tree varieties are the hardiest. The cold-hardiest avocado tree varieties are the Mexicola (18 to 20 degrees), Duke (22 degrees), as well as Ganter and Topa Topa (23 degrees).
Plant the hardy avocado trees in an area that receives full sunlight and has up to 20 feet of space for each tree to grow. Select a planting site that has loose, well-draining soil. Plant the avocado tree near your house for additional protection from cold if you live in a colder region.
Water the trees enough to moisten the soil the depth of the roots two or three times per week during the growing season. Water the trees only during prolonged dry spells or droughts during the fall and winter.
Feed the avocado trees four times each year with a 10-10-10 NPK fertilizer after one year of growth, and follow the dosage instructions on the package.
Wrap the trunk of the tree with a foam pipe sleeve during hard freezes in winter. Harvest all the avocado fruits before the first frost.
Whitewash the tree's trunk, from the ground level to the first set of branches, to protect the tree from sunburn. Hardy avocado varieties especially need this protection.