Growing an avocado plant from the fruit's pit is a popular science project for school-age children. The project is simple to set up, requiring just a few household items. Although you can grow an avocado tree from a pit, the fruit will taste different than that from an avocado tree purchased from a nursery, according to the California Avocado Commission. Additionally, it can take up to 15 years for an avocado tree to begin producing fruit.
Wash the pit from an avocado to remove any remaining fruit.
Fill a glass or glass jar with water.
Insert three toothpicks or wood skewers into the avocado pit. The toothpicks should be inserted about halfway down the pit, and be spaced an equal distance apart.
Place the avocado pit on the rim of the glass so it hangs on the toothpicks. Half the pit should be submerged in the water and half above the water. The pointy part of the tip should face upward, and the rounded part of the pit should sit in the water, according to the University of Nebraska-Lincoln Extension.
Set the glass in a warm and sunny location such as in front of a window. Within two to four weeks, you should see sprouts that will form the roots and stem of the tree.
Replenish the water in the glass as necessary. How often this will need to be done will depend on heat and humidity, but the bottom of the pit should remain in the water.
Cut the stem back to 3 inches in length once it is 6 or 7 inches long. You can use scissors or other pruning tool to cut the stem. No leaves should remain on the stem once it is cut back.
Fill a flowerpot that is 10.5 inches in diameter with potting soil. For best results, use a rich humus soil, according to the California Avocado Commission.
Transplant the avocado pit from the glass to the pot, leaving the top half of the seed exposed, once the root has thickened and the stem has sprouted leaves, according to the California Avocado Commission. The pot should be placed in a sunny location.
Water the plant lightly and frequently, with occasional deep waterings.
Cut the stem back to 6 inches once it reaches a height of 12 inches. After this, you can allow the tree to grow without any additional prunings.