Growing an avocado pit (or stone) is an interesting project for a child and a fun way to grow an attractive houseplant for free.
To grow an avocado pit:
- Find a ripe avocado. Avocado pits are most likely to grow if they come from a ripe fruit. When you eat the avocado pear, clean off the pit and then soak it for 48 hours in warm water. If you can keep the water warm (in a propagator or on top of a heater), then the pit will grow more quickly.
- Find the top. Most avocado pits are egg-shaped, with the bottom broader than the top. Some are rounder, but the top is always smooth and the bottom, wrinkled.
- Find a container. If you want to see the roots grow, you will need a clear container, such as a tumbler or a jar. Otherwise, a plant pot will do fine.
- 'Plant' your pit. To see the roots grow, you need to suspend the pit above water. Find 3 or 4 toothpicks or hair grips and push them into the pit gently, until they will just support its weight. Then fill the container with warm water so that the bottom of the pit just touches the water. If you're using a plant pot, then bury the pit in potting compost so that half of the pit is still above the soil.
- Keep warm. Warmth is the key to getting an avocado pit to grow. The ideal temperature is around 70 F. At this temperature, the pit should start to grow in around 10 days. At cooler temperatures, it can take 5 weeks.
- Keep watered. Keep the water level in your container topped up so that the pit is just touching the water. If you planted your pit in compost, then keep it moist - putting it in a plastic bag will help.
- Keep an eye out for growth. The first sign of life will be root growth, which will not be visible if your pit is planted in compost. Only when the roots have started to grow will the pit send out a shoot. If the water goes cloudy and starts to smell before this happens, then your pit will not grow. If this happens, it probably wasn't fertile to begin with, and you should start again with a fresh pit.
- Pinch out the main shoot when it is 6 inches long. This is to help make a bushy plant rather than a tall tree. It may leave your avocado with no leaves, but don't worry - it will grow a new shoot and new leaves in about a week.
- Re-pot. Your avocado plant can survive on just water for several weeks. When the roots are well developed, plant the avocado in potting soil in a small pot. It will be happy there for several months.
- Move into a final pot. When the avocado looks too large for its pot, or unhappy, it is time to replant it in a 10-inch pot, which will be its permanent home. It will probably be 2 feet tall before this is necessary.
- Pruning. Your avocado wants to grow into a tree, and you will need to keep pruning it to keep it bushy and manageable. Simply cut back shoots that are too long.
- Ongoing maintenance involves feeding with liquid feed every two weeks when the avocado is actively growing. Every 3 or 4 years, replant it in the same pot with some fresh potting soil. Your avocado will need plenty of light and water plus an occasional misting and dusting.