In this system it is very important the variety that you choose to plant your orchards. The majority of olive varieties begin production not before the fifth or sixth year, and are too vigorous to fit in this system. After trials with more than 100 Spanish, Italian, Greek and French varieties, the clones Arbequina I-18, Arbosana I-43, and Koroneiki I-38 have been shown to be the best varieties for high density orchards. These clones are designed to grow slowly, mature early, bear abundantly with an olive that has a fruity, delicate and elegant top quality olive oil.
Olives trees are able to grow in ground where nothing else can grow. High salt content, rocky soils can be suitable for olive trees. Also, they need a small amount of water. That makes a big difference because the grower can find inexpensive land and does not need too much water avaibility. Some farmers say that the most difficult tree to kill is an olive tree.
Typical spacing of varieties for high density orchards (Arbequina I-18, Koroneiki I-38, and Arbosana I-43) is 12-13 feet between rows and 4-6 feet between trees, depending on the type of soil.
The trees are produced in pots, they have a healthy and well developed root system, so once the ground is ready and the irrigation system is installed, they can be planted at any time of the year. This offers a big advantage of planting flexibility to the grower and dramatically reduces the number of losses.
Varieties used in high density olive orchards are pruned to a central leader. A bamboo, wooden stake or metal pole must support the plant to be trained in the first three years. The tree stakes are supported by a one-wire trellis system with end poles and metal stakes spaced for support of the wire down the row. The trees are not headed when planted and are allowed to grow up the stakes in a central leader fashion. The tree canopy is kept to about 2 feet above the orchard floor and topped to a level of 7 feet.
By using over-the-row mechanical grape harvesters, expensive hand labor is all but eliminated, harvesting time is much shorter, and the olives do not fall on the ground. You can harvest at the perfect ripening time, that way olives can be processed much faster. All these factors are critical to having the highest quality of extra virgin olive oil.
A typical two-man grape harvester can be used to effectively harvest 1 to 1.5 acres per hour.