Starting an avocado tree from seed is not difficult. However, it can take 10 to 15 years for avocado trees planted from seed to bear and the trees may not grow true to the variety from which the seed was taken. If you are looking for a tree that will bear more quickly and that will produce a known avocado variety, planting a nursery tree is a better option than starting one from seed. However, planting a tree from seed is a good way to plant an ornamental tree that may, or may not, eventually bear fruit.
Rinse a fresh avocado pit. The pit should be started immediately after the donor avocado is eaten. The longer the pit is allowed to dry, the lower the chances of germination.
Poke three toothpicks into the pit. Make sure the toothpicks are inserted deep enough to secure the pit when placed on the rim of a water glass.
Place the pit in a water glass with the toothpicks resting on the rim of the glass.
Fill the glass with fresh water until the lower half of the pit is submerged.
Place the glass in a sunny window. Change the water every couple of weeks until you have an inch or two of roots growing from the bottom of the pit.
Plant the sprouted pits in a pot with potting soil. Keep the soil moist, but not soaking wet, to encourage growth. Grow your young tree in a sunny window.