Basic Planting & Care Information
It is always better to plant in areas where olive trees have been farmed for at least a few years. The presence of healthy and productive trees is reassuring while projecting a new planting. If you are the first to plant in a new area, it is wise to study the weather records for at least 10 previous years. If the records are not available, you many want to plant a test plot only. A test plot should not be bigger then 10% of your potential growth area, where you can establish that the area is suitable for farming and production.
Olive trees grow well in a variety of soils, from very sandy to clay loams. The texture of the soil is to be considered only in extreme cases. If the soil is too sandy, the organic matter will be too low, and too much clay will interfere with root growth, which will cause root suffocation. It is very important to have well-drained, loose and aerated soil. Fallow land with a history of soils being compacted by cows or other factors, should be ripped at least 2’ deep after the field is amended. In cases where a ripper cannot be used, it is suggested to dig holes of at least 4’ square and 3’ deep.
Direction and Spacing of Rows
In most cases a layout should be rectangular and whenever possible, evenly spaced rows should run north to south. This row direction will limit shading between trees, which will help to contain diseases, and will maximize sun exposure to the fruit. Spacing depends very much on the vigor of the cultivar(s), weather and soil conditions of the site, and farming equipment intended to be used. Low vigor cultivars for intensive planting should be planted between a spacing of 12’ X 6’ to 15’ X 7.5’. The less optimum the growing conditions, the closer the spacing within these ranges. The more optimum the growing conditions the greater the spacing within these ranges. Regular vigor cultivars, about 90% of existing cultivars, should be planted between a spacing of 17’ X 9’ to 20’ X 14’. The less optimum the growing conditions the closer the spacing within these ranges. The more optimum the growing conditions the greater the spacing within these ranges. Note: Optimal growing condition for olive trees doesn’t always pair with optimal condition for farming, quality of product and or cost management.
The best and most cost effective way to stake olive trees is with bamboo stakes held in place by 1 or 2 wire(s) running from end post to end post and supported with middle posts.
There are 3 basic different pruning methods for olive trees.
- Forming Pruning: The pruning depends on the age and the conditions of the trees. A tree, which was well cared for in the nursery, once in the field, should be pruned for the first 2 to 3 years only to help it achieve the shape the grower has chosen (forming pruning). The most common shapes used for mechanized and functional groves are the Monocone and the Vase.
- Production Pruning: Once the tree enters its productive life, the tree is pruned to maintain constant production avoiding alternating cycles and to ease picking. This is obtained by thinning the canopy (production pruning) and by eliminating the majority of suckers, crossed and tangled branches. The ratio between suckers and productive canopy is essential. While most suckers need to be cut off, a few left throughout the productive areas guarantee a flow of sap to those areas, which is essential to production.
- Reform Pruning: The third type of pruning is called restoration or reform pruning. This type of pruning is performed on rare occasion such as when a tree has grown too much, or it is intended to change its shape or when an adult tree is transplanted.
Watering incorrectly can kill or slowdown the growth of olive trees. In order to water correctly, weather, water table, soil texture, density and drainage should be considered. Water schedule can vary from a few times per season to 3 or 4 times per week. Monitoring how quickly the soil dries out after watering will help determine a watering schedule. Newly planted trees should be sufficiently over-watered for the first 2 to 3 weeks, and then put on their optimal watering schedule. Not watering enough can kill a tree immediately. Look for dry, opaque and curled leaves as signs of water stress. Over-watering can also kill olive trees but the process will be longer. Olive trees roots love water but can’t stand wet feet, they rot if they are constantly wet. Look for signs such as defoliation on the lower part of branches, yellowish leaves throughout the canopy and rubbery branches to recognize over-watering stress.
Olive trees as most of plants mainly need Nitrogen, Phosphorus and Potassium in order to grow and produce. Every season they consume a certain amount of these nutrients depending on their size and on how much they grow and produce in that season and the grower should replenish them with regular applications. Generally speaking it is always better to apply a complex fertilizer, which contains higher amount of nitrogen, from early spring to early summer, and then reduce the amount of nitrogen for the rest of the season. Higher potassium during summer and fall is optimum for fruit development. It is also important that the microelements are well balanced with special attention to Boron, which is essential to bud and flower development.
The greener the olive, the higher are the contents of chlorophyll, the darker the olives the higher are the contents of carotene. Higher level of chlorophyll will most likely produce oils very lean in density, with greenish color, aromas of green apple and/or fresh cut grass with a pungent and bitter taste. These oils will generally contain higher levels of antioxidants. Higher levels of carotene will most likely produce oils with yellowish color, thicker density, aromas of chamomile and/or straw, with a buttery nut taste. These oils will generally contain lower level of antioxidant. The quantity of oil within the olive increases up to the time when the fruit starts to turn black. After that the olives only absorb water. Usually, olives should be picked when the majority of them are around this maturation stage, which in Italian is called “Invaiatura”.
Every location and site has its specific conditions and needs as well as each grower, therefore we urge you to seek professional advice on your specific needs, situation, area, and site, prior to starting your olive production project.