Nowadays the olive tree is grown for commercial or personal use all over the world. Although an olive tree can live over a thousand years, like many other plants, certain conditions need to be met for it to thrive. Read on if you want to grow an olive tree from when it is small to maturity and if you want to know the tricks used by farmers to obtain delicious fruit and flavorful oil.
Steps
Part 1 of 3: Creating the Right Environment
Step 1. Define if it is possible to grow olive trees in your region
This crop develops best in climates with mild winters, long, dry summers. The most suitable geographical areas are the Mediterranean area and the coastal valleys of California, while it is difficult - even if not impossible - to cultivate the olive tree in tropical climates.
- Frost can kill trees if you don't take care of them. Temperatures that reach -6 ° C can harm small branches; when they drop below -9 ° C they can kill larger ones and even entire trees. Although branches and trees can survive the cold, the flavor of the olives and the resulting oil may be affected by frost. Therefore, avoid growing this plant if you live in a geographic area prone to such temperature drops.
- However, the olive tree needs a certain amount of cold; for the flowers to develop correctly, temperatures must also drop beyond 7 ° C, although this value may vary according to the type of olive tree you are growing. This is why its cultivation is extremely difficult in tropical climates and very hot regions.
- Make sure the flowering season is dry and with moderate temperatures. The months of April-June (when the olive tree blooms) should be quite dry and not too hot; pollination occurs through the wind, therefore atmospheric conditions can hinder fruit development.
Step 2. Check the pH of the soil and modify it if necessary
The soil should have moderate acidity or alkalinity and the ideal pH should be between 5 and 8.5; most growers believe that the ideal value is 6, 5. To perform the test you can go to a private laboratory or use a home kit that you can buy at garden centers, nurseries or even online; if the pH is not within the ideal range, adjust it as needed.
- Limestone is used to increase the pH of the soil, while sulfur is used to lower it; you can buy both products in powder or pellet form online, at garden centers or hardware stores.
- You can adjust the pH by spreading sulfur or limestone on the soil; the right dose depends on how much you need to change the acidity (or alkalinity) value; to do this, read the instructions on the package. It may take a few days for the substances to be properly absorbed into the soil.
- Once the pH reaches the right levels, continue to control it throughout the plant growth process, especially after using fertilizers that can modify it; periodic intervention may be necessary during the development of the olive trees.
Step 3. Look for an area with good drainage
Observe how water affects the soil in the area where you want to grow olive trees. These plants thrive in well-draining soil; check it after a rain and do not grow in spaces where puddles form. To check the drainage, dig a hole 60 cm deep and pour some water; if it remains stagnant without flowing away, choose another area.
Planting trees on slightly sloping ground can solve many drainage problems, as the slope helps to drain the water away
Step 4. Preferably look for spaces where olive trees have already been grown in the past
The best indicator to ensure successful cultivation is the presence of healthy olive trees in the same land in the past. If you know these plants have already been grown, choose the same place; eventually, you can also opt for an area adjacent to other existing olive trees.
If you know other farmers or gardeners nearby, ask them where they have grown these trees in the past
Step 5. Find a space that is exposed to direct sunlight
The ideal is an area in full sun, without shaded areas that can block the light rays. Whichever place you choose, make sure it gets direct sunlight for at least six hours a day; shaded places are not recommended for growing olive trees.
Part 2 of 3: Plant the Trees
Step 1. Bury them in the spring
Frost can be the main danger for young olive trees; in general, you have to plant them in spring, when the temperatures remain constantly higher and there is no longer the risk of frost. Most gardeners plant them between April and May, but consider the best time based on the region you live in.
The more time they have to develop before the next winter, the better; plant them as soon as possible after the last expected frost of the cold season
Step 2. Start with the seedlings in the pots
Buy small olive trees online or at garden centers. Growing from seeds is a difficult process, because they are very delicate; instead choose plants that are already 1, 2-1, 5 m high and whose branches are already 90 cm long.
Step 3. Dig a hole that is about the same size as the pot the sapling is in
Measure the container - including the outer circumference and height - and dig the soil based on this data. A precise calculation is not necessary, but make sure that the hole is large enough to comfortably accommodate the entire root system of the seedling.
Step 4. Remove the sapling from the pot and check the roots
Remove it taking care to free the entire root system as well; Cut or loosen tangled roots as best you can, but do not touch the root ball, otherwise you could damage the plant.
Step 5. Fill the hole
Use the same soil you dug before and the surrounding soil to fill in the rest of the hole; put 2-3 cm of soil over the root system. Do not add enriching material such as manure or compost at this stage, as the tree should initially grow from the original soil.
Step 6. Install water diffusers near the logs
It is a drip irrigation system that allows the olive trees to receive an adequate amount of water. During the first year you should place a diffuser next to each individual trunk, while the following year you should move it about half a meter from the trees; you should also add a second sprinkler system, always half a meter away from the logs.
- Installing the water diffusers is a rather complicated process. While you can buy them at a hardware store, positioning them correctly and putting them into operation is a complex task if you are not an experienced gardener; therefore consider appointing a competent professional in the sector.
- These diffusers are usually connected to a water source, for example an external tap; a pipe is then attached that runs through the entire field or garden to reach the base of the plants. At this point, it is necessary to create holes along the entire pipe and install a hydraulic device to irrigate the olive trees.
Step 7. Water and add straw based mulch
By using the drip sprinkler you should be able to water the plants properly.
You can use other types of mulch instead of coarse straw; alfalfa, soy, pea hay - just to name a few - are perfect, packed with nitrogen and other valuable nutrients
Part 3 of 3: Feeding the Plants to Maturity
Step 1. Water and irrigate the olive trees in moderation or as needed
With the drip irrigation system, trees need to receive water every day during the summer season; water them for an hour. You can also keep mini diffusers open to wet the ground within a radius of 60 cm from the trunk and keep the olive trees properly hydrated. Look for models that distribute about 2-4 mm of water per hour and place them between the various trees.
The frequency of watering depends on whether you want to grow the plants for fruit or oil. If you opt for olives, more frequent watering is required, which can vary from every week to every two or three; if you want to produce oil, it is necessary to wet the plants less frequently, so that the aroma is more concentrated
Step 2. Prune the olive trees regularly
Don't cut young branches often; during their first year of life you should limit yourself to detaching those that develop at a height of less than 90 cm; as the plant grows, it takes on its final shape and you can eliminate any weak or unwanted branches. However, early pruning should be minimal to avoid blocking the olive tree's development.
Step 3. Manage diseases and parasites
Like most plants, olive trees are also susceptible to diseases, especially cochineal half a peppercorn, or Saissetia oleae. As a farmer you need to find a good balance between organic farming and protecting trees from disease and infestation. In some cases it is necessary to resort to insecticides; evaluate the different possibilities with an expert to get the best results.
- Half peppercorn cochineal causes black scales to form on the bark and the infestation can easily get out of control, as these insects quickly lay many eggs. Although such pests affect trees that are already sick, healthy ones are not immune; if you spot the signs of these insects, apply the appropriate substance right away.
- Verticillium is a fungus that can affect olive trees causing the leaves and branches to wither unexpectedly; although some cultivars are resistant to mycosis, remember that there is no treatment. If you do not remove the already affected branches, the disease spreads to the whole tree; in this case, you must also prune the very young specimens. If you have faced mycosis in the past, avoid planting new olive trees in the same soil.
Step 4. Apply a moderate dose of fertilizer
These trees are able to thrive even with just water and the right care, although a mild fertilizer can promote development; choose a mildly aggressive product and spread a minimal amount during the growing season. The instructions on the package should state how to use; generally, the fertilizer is sprinkled directly on the soil. Use the smallest amount possible, preferring to err on the side of things rather than excessively.
The packages of fertilizers generally report the proportions of the substances that make up the product and indicate the quantity of nitrogen; for olive trees you should use a 10-10-10 or 13-13-13 fertilizer
Step 5. You have to wait several years for the tree to bear fruit
A well-watered olive tree begins to produce olives two to three times faster than a dehydrated specimen. While some cultivars can be harvested at two or three years of age (if well grown), many are not productive until 10 years. When growing these trees, remember that this is a long-term project; you may notice a few olives after the first two years, but be aware that it takes a lot longer to actually harvest.
Step 6. Determine when to reap the rewards
Initially, they are green but turn black when fully ripe. Olives harvested while still green have a grassy and peppery flavor, while those that have ripened on the tree are more delicate and buttery. Many oils are made from a blend of green and black olives that are harvested as they change color. Decide what kind of olive you want and wait accordingly.
Remember that you cannot eat olives immediately after removing them from the tree; most must be preserved in brine, a mixture of water and salt, before consumption
Advice
- An olive tree can also grow in a very large container indoors.
- The trees can reach 15 m in height and the fronds spread up to 9 m in diameter.
- It is possible to plant an olive tree on sloping or terraced land, but in this way the harvest becomes more complicated.
- To prevent olives from growing in certain places on the plant, prune the flowering branches in early summer.
Warnings
- Check that the pruning tools are clean when you cut the plant in the rainy season; the blades could become contaminated with olive mange, a bacterial disease that spreads from tools.
- The mycosis caused by verticillium can affect Californian olive trees; you can avoid it by removing diseased specimens and branches and giving up planting new trees in infected soil.
- Do not spray chemicals on the olive trees you grow for oil, because the latter retains the odors of the substances.
- The Mediterranean fruit fly and the olive fly are insects that can damage trees that grow in the Mediterranean area.
- Ripe olives dent easily and must be handled with care during harvest.
