Avocados feature tough, wrinkled green skin and light green, creamy inner flesh with a seed in the center the size of a pingpong ball. The wrinkly skin gives avocados the additional name "alligator pear." These subtropical trees grow best in warm areas with mild winters. Those living in areas where temperatures dip below about 35 degrees Fahrenheit should not grow avocados in the ground. Avocados, however, can do quite well in pots in all climates and seasons.
Wash an avocado seed in cool water to remove the avocado flesh. Microwave about a cup of water in a glass measuring cup for about 45 seconds. Soak the seed in the warm water (about 105 F) for about a minute to eliminate mold and bacteria potential. Cut about a quarter inch of the pointed end away and dip the cut part in liquid fungicide.
Fill a 16-oz. pot with sandy potting soil. Push the seed, rounded end down, into the soil. Leave the cut part and the top one-eighth inch below it exposed. Water the soil around the seed until the soil is damp but not muddy.
Place the avocado seed in a warm, sunny window or outdoors in the summer. Water the seed as before every three days until it grows about 6 inches high.
Fill a five-gallon pot with sandy soil. Transplant the seedling to the new pot, untangling the roots before settling it into a hole as large as the root ball. Cover the roots, and water as usual. Leave the avocado tree outdoors as long as it is warm.
Move the potted avocado tree indoors when the nights cool consistently to 50 F or below. Place it in a room with plenty of natural light and keep the temperatures no lower than 60 F. Water as usual, and make sure no drafts come through the windows.