Stop Buying Avocados. Here’s How to Grow an Avocado Tree from Seed

Roots and Sprout Development Once the roots are a few inches long and the stem has grown to about 6 inches its time to transplant the seedling
into soil.
Planting in Soil Choose a large pot with good drainage holes and fill it with a welldraining potting mix. Make a hole in the center of the soil and gently place the seedling inside ensuring the top half of the seed is above the soil surface. Water the plant thoroughly after planting.
Caring for the Avocado Tree Avocado trees need plenty of sunlight so keep your plant in a sunny location. Water the tree regularly but be careful not to overwater as avocados 

prefer slightly dry soil. Allow the soil to dry out between watering sessions. Fertilize the tree with
a balanced fertilizer during the growing season.
Support the Plant As your avocado tree grows you might need to provide support for the stem. Use a stake or tie it to a trellis to ensure it grows straight and strong.
Pruning Once your tree is established you may need to prune it occasionally to encourage branching and maintain a desirable shape.
Patience is Key Growing an avocado tree from seed takes time and patience. It can take several years before your tree produces fruit and theres no guarantee that the fruit will be the same as the parent avocado you used to start the tree.

Remember that not all avocado seeds will successfully grow into healthy trees and even if they do they may not bear fruit. However its a rewarding and educational process and the lush green foliage can make for a beautiful houseplant even without fruit. Happy growing!