When planting avocado trees from pits, give the pits sufficient time to develop roots. Rushing them and putting them in the ground too soon will most likely kill them. Avocado trees come from Mexico, the West Indies and Guatemala. The tropical plants need very warm climates to survive outside. They do well in USDA Hardiness Zones 9, 10 and 11 and will produce fruit in about 10 years. If you live in other parts of the country, plant avocado trees for use as a houseplant.
Run the avocado pit under cool tap water to wash away fruit residue. Scrape away stubborn debris with your fingertip, if necessary. Blot it dry with a towel.
Stick three or four toothpicks into the middle, fleshy part of the pit. Evenly space them out around the pit so they can act as a brace to hold up the seed.
Fill a drinking glass or vase almost to the top with tepid tap water. Place the avocado pit in the glass so that it's suspended from the ridge, held up by the toothpicks. Immerse the pit so that it is 1 inch into the water. If there isn't enough water, add more.
Set the glass in a sunny indoor spot. Allow three to six weeks for the pit to split open. Add more water if some evaporates. Wait for stems to sprout out of the top and roots to grow from the bottom of the pit.
Pluck off the top set of leaves by hand when the plant reaches 5 inches tall. Let a new set of leaves and roots grow over the next couple of weeks.
Transfer the young avocado plant from the glass to a flower pot. Fill the pot with a few inches of soil and set the plant in the center. Fill the rest of the pot with soil. Water until moist and keep the container in a location that gets sun.
Move avocado plants to larger containers in the spring so that the roots have more room to grow. Give the avocado plant a diluted liquid food twice a month. Follow the instructions on the label. Water the plant to keep the soil moist to the touch.
Choose a protected spot outdoors if your climate is warm enough to plant avocado trees outside. They are susceptible to sun damage because they don't have bark, so choose a spot under the shade of another tree.
Plant avocados in the spring, once the threat of frost is over. Dig a hole two to three times as wide as the tree's root mass. Place the tree in the hole and then fill it back up with an equal amount of the removed soil, compost and sand. Pat it down firmly and water until moist.