An olive tree, or Olea europaea, is an evergreen tree native to many parts of the Mediterranean region. Planting olive trees can be done using either seeds, known as pits, or seedlings sold in pots at most nurseries. Olive trees planted from seeds may not produce much fruit, though, if any. These trees must be planted in the right type of climate and soil, and special care should be taken during planting and during the first few years for the tree to thrive.
As olive trees are native to the Mediterranean, they prefer milder climates. Warm, sunny regions are best, and planting olive trees in wet regions or where the temperature drops below 15 degrees F (-7 degrees C) is not recommended. Also, these types of trees have a shallow root system, and areas with frequent periods of high winds may not be the best place to plant an olive tree. The winds can uproot the tree and, possibly, cause the fruit to drop too early, resulting in a poor crop.
Olive trees can often grow in a variety of soil types. It is believed that mildly fertile soil is best, though. The soil should be well-draining because these trees prefer a somewhat dry environment.
When planting olive trees from a pot, the hole should be dug approximately the same size as the pot. Without disturbing the root ball too much, roots that are tangled or circling the outside of the root ball should be untwisted or cut, and the tree can be placed in the hole just below the surface. It is recommended that the root system be placed no more than 1 inch (2.5 cm) below the surface, and the root ball should fit snugly into the hole.
To ensure proper growth, many experts agree that pruning and shaping of the tree should be kept to a minimum in the first few years. One strong main trunk should be left, along with five or ten of the strongest top branches. If, after planting olive trees, they seem to lean or fall over, the top branches can be pruned, or they can be staked until they are able to stay upright.
Watering olive trees is recommended until the tree is established. To ensure that the trees are not over watered, gardeners can install a drip irrigation system. After new growth begins to appear on the trees, they do not need to be watered as much. Gardeners can then gradually reduce the amount of water given to the trees and, afterward, only water them during dry spells.
If a gardener is planting olive trees simply for the crop, to make olive oil, for example, more than one tree would be ideal. Depending on a number of factors, an average olive tree will produce between 10 and 500 pounds (4.5 to 227 kg) of olives each season, and it takes roughly 40 pounds (18 kg) of olives to make 1 gallon (3.8 l) of oil. Younger trees will generally produce fewer olives. If a person is planning to produce a few gallons of olive oil, a small olive tree garden is usually preferred. In this case, many experts agree that the trees should be placed no less than 20 feet (6 m) apart to allow for maximum growth.