You can grow your own avocadoes.
image by HarmonyRae/flickr.com, Maria Keays/flickr.com
If you love avocados, the next time you eat one don't throw the seed away. Growing an avocado tree from the seed is a fun project to share with your kids. It's very easy to do, and you'll all love watching the baby plant emerge from the seed and grow into a tree that can be enjoyed as a beautiful houseplant. If you live in zones 9 to 11, where sustained winter temperatures don't remain below 45 degrees F, you can plant your avocado seedling in your yard. Edible fruit will begin developing on your seed-grown tree in 3 to 15 years, depending upon the variety.
Sprouting the Seed
Remove the seed from a ripe avocado and rinse it well under cool water to remove any of the fruit's flesh that might be clinging to it. Pat the seed dry with a paper towel.
With the pointed end upward, carefully push 3 or 4 toothpicks about ½ inch deep into the broadest part of the pit. Space the picks more or less evenly apart.
Place the rounded bottom of the seed in a drinking glass, resting the toothpicks on its rim. Pour enough water into the glass to cover about an inch of the base of the seed. Set it on a warm, bright windowsill out of direct sun. Replenish the water as needed. The seed will begin to split open in 2 to 6 weeks, and a stem and some roots will sprout.
Pinch out the top set of leaves when the avocado seedling's stem is about 5 or 6 inches tall. In two to three weeks, the roots will thicken significantly, and new leaves will sprout. The avocado tree seedling should be potted once the leaves and roots are well formed. The plant will begin to deteriorate if it isn't planted in soil within a month or two of germination.
Fill a 10-inch pot with well-draining organic potting soil to about 1 inch from the top. Make a slight impression in the center of the surface with the heel of your hand. Remove the toothpicks from the pit and place the seedling roots down in the depression. Cover the lower portion of the seed with soil, leaving the upper half exposed. Firm the soil gently around the roots and seed. Thoroughly moisten the soil with water, but not so much that it's soggy.
Set the potted seedling on a warm, sunny windowsill. The tree needs all the direct sun that you can provide from now on. Water frequently but lightly, just enough to evenly moisten the soil. If the leaves begin to turn yellow, you're watering too much; let it dry out for a few days before watering again.
Feed your avocado seedling a dilute liquid fertilizer every other week once the leaves and roots are thriving. When the stem has grown another 6 inches tall, pinch out the top two sets of leaves. Thereafter pinch the leaves back every time the plant grows another 6 inches to encourage the branching of side shoots.
Planting the Tree
Select a well-draining sunny spot outdoors for your avocado tree in the spring, when nighttime temperatures no longer drop below 50 or 55 degrees F. The ideal time for transplanting outside is typically March through June. Avocado trees planted in the shade will grow, but they won't produce fruit.
Dig a hole as deep and a little wider than the tree's pot. Try not to disturb the delicate root system any more than necessary when removing the tree from its container. If it has become root-bound, loosen the soil around the edges gently with your fingers. Cut away any roots that have grown into a circle. Position the tree in the hole so it will be planted at the same depth it occupied in the container. Backfill the hole with the soil, not potting medium.
Water the newly planted avocado tree thoroughly, enough to evenly moisten the soil. Thereafter keep it moist but never give it so much water that it will be soggy or waterlogged.
Feed your avocado tree a good, balanced fruit tree fertilizer four times each year.