It isn't easy to grow an olive tree from an olive. The pit must be from an olive that has freshly dropped from a tree, and it can take up to a year to germinate. The tree eventually grows may not bear fruit. But olive trees are highly ornamental, so no matter what, you will have a striking tree for your landscaping. Olive trees thrive in warm, dry climates with mild winters. The official USDA hardiness zones for the olive tree are 10 and 11, but some varieties do well in zone 9.
Collect the olive from the ground on the day that it drops. Use pliers to carefully crack the outer shell of an olive pit. You don't need to break it, just create a crack so that water and nutrients can get to the embryo.
Moisten a handful of sand. Push the olive pit into the moist sand. Place the sand into a plastic bag and put it in the refrigerator. Leave it there for 90 days.
Mix together equal parts of sand and vermiculite. Pour the mixture into a 6-inch (diameter) planting pot. Water it until the mixture is saturated and water drains from the bottom of the pot.
Remove the olive pit from the refrigerator and push it 1 inch deep into the soil.
Turn the heat mat on and set it to 70 degrees Fahrenheit. Place the planting pot on the mat and allow it to remain until it sprouts. Once the olive sprouts, which could take up to one year, place the pot on a sunny windowsill.
Water the soil in the pot to keep it moist while the pit germinates.
Transplant the tree into the garden in the spring when it reaches 3 to 4 feet in height. Don't amend the soil prior to planting it in the ground, just dig a hole the same depth and height as the pot, place the roots into the hole and backfill with soil. Set a soaker hose next to the base of the tree and run it for 1 hour, daily, during the summer.