The next time you make guacamole, save the pits from your avocados. You can grow your own avocado plant from the seed inside any grocery store avocado. If you live in a warm climate like California or Mexico, you can grow avocados outside and harvest your own fruit in a few years. Gardeners in cooler regions can grow avocado trees as unique houseplants, although you probably won't ever get any edible avocados off of them.
Use a knife to carefully cut around the pit inside the avocado. The pit is about 1-1/2 inches in diameter and is located at the center of the fruit. Cut through the flesh all around the pit, then gently twist the two halves of the avocado to pull them apart. Discard the skin, use the green flesh in guacamole, sandwiches or salads, and set the pit aside.
Rinse the pit under running water to remove any residual fruit.
Prepare a container in which to grow your avocado. You can start with a pot that is about 6 inches in diameter, and it should have drainage holes on the bottom. Fill the container with all-purpose potting mix.
Bury the avocado pit so that the flatter end is on the bottom and the pointier end is sticking up. The pointed end of the avocado pit should just poke above the surface of the soil.
Place the container in a warm location in full sun, such as a south-facing window, or outside in the summertime.
Water thoroughly and keep the soil evenly moist. Depending on the weather and the age of the original fruit, your avocado pit should sprout in one to four weeks.
Feed your avocado plant one to four times a year with a general or houseplant fertilizer.
Repot your avocado once a year in the spring. If you live in zones 9 through 11, you can transplant your avocado outside once it is established. Avocados prefer well-drained sandy or loamy soil and need lots of room to spread out. Outdoor avocados will benefit from an annual dose of nitrogen fertilizer in the winter.