How to Grow an Olive Tree and Make Olive Oil
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Growing your own olives is a lot less difficult than most folks may think – and doing so will provide you with a sustainable stockpile of this highly versatile oil. We’ll go through how to grow an olive tree and how to make olive oil.
Indoor Olive Tree & Growing Zones
Olives are traditionally grown in a subtropical climate, particularly USDA growing zones 10 and 11. But, if you cultivate dwarf olive trees, have a greenhouse, or have enough space and the right light inside your home, olive trees can also be grown in containers and moved indoors during the winter.
Make sure you choose an olive tree variety that’s suitable for growing in containers if you want to grow an indoor olive tree or keep your tree on your patio. The Arbequina olive tree (Olea europaea “Arbequina”) is highly adaptable, does well in the ground and containers, and is self-pollinating. It grows more olives if you have other varieties planted nearby, however, so consider choosing another variety as well.
Some folks have had luck growing olive trees outdoors down to USDA growing zone 5, as long as the trees were relocated to a greenhouse or grown as indoor olive tree during the cold weather months.
The Arbequina olive tree is also available on Amazon as smaller plants:
There are some olive tree plant varieties that are more cold-hardy than others. For example, the Leccino olive tree (Olea europaea “Leccino”) is very adaptable to weather conditions. It will grow well in areas where the winter temperature goes down to 50 degrees, just above freezing.
It’s best suited to zones 8 and 9, but some people successfully grow it in parts of Oregon and the Northwest! The Leccino olive also grows well in containers, which means you can bring it indoors in winter if you need to. This olive tree plant starts producing after only two years, and you’ll have a full harvest after 6 to 8 years.
History of Olive Trees and Olive Oil
Olive cultivation predates 300 B.C. and is believed to have begun in Syria. The growth of olives spread rapidly into both ancient Rome and Greece. By 900 B.C., Homer referenced not only olives but olive oil as one of the essential parts of the then-modern culture.
It was not until 1803 that olive oil was first known to be produced in the United States. The first known commercial olive oil mill began in California in 1871. Just a few decades later, when the still-young olive oil industry started to focus exclusively on the production of just olives, did it become apparent they could not compete with the far lower-priced olive oil being imported to America from Europe.
The California table olive production thrived and did not turn again to the production of olive oil until the latter years of the 1980s. The initial effort by a handful of olive growers determined to fulfill a need in the gourmet olive oil market once again began planting oil-grade olives. Now, more than 10,000 acres in the state are devoted to olive oil production.
How to Grow an Olive Tree Plant
So, how to grow an olive tree in your own garden? Olive trees can grow to live for hundreds of years – some perhaps even a thousand years old. These evergreen trees have shallow roots. The olive fruit appears on new wood growth from each previous year, making olive trees an alternate bearing fruit.
The structure of an olive tree’s growing pattern allows it to both produce and support a bountiful crop of olives. But, not much new wood growth occurs when a large crop is being supported, which often results in a smaller crop the following year. Diligent and careful management of shoot growth can help you keep your olive tree production from experiencing extra large or extra small yields.
Pruning the abundance of flowers that grow on an olive tree during a single year can help prevent it from producing too heavily – causing a smaller yield to generate during the following growing season. Pruning olive trees becomes even more vital during poor weather and when pollinators are in short supply. Even though olives are nearly self-fruiting, they do benefit greatly from nearby pollinator trees.
Olive Tree Care Tips
These trees require a bit of special, unique care to thrive.
Olive Tree Soil & Planting
- An olive tree can not only survive but thrive on land that is suitable for little else to grow, like rugged hillsides with dry or poor soil.
- Olive trees are exceptionally drought hardy.
- The one surefire way to kill an olive tree, as quickly as exposing it to chilly temperatures, is to plant it in soil that does not drain well. Olive trees, especially the roots, loathe being damp or wet. But, young olive trees can tolerate and even thrive when kept only slightly more moist than mature trees.
- Olive trees were once planted from 30 to 60 feet apart, but most modern commercial orchards now plant the trees 8 to 20 feet apart to conserve space as part of “high density” growing operations.
- Olive tree rows are typically placed 16 to 24 feet apart.
The Best Climates For Growing Olive Trees
- Olive trees are fragile when the temperature drops below 22 degrees. Frost damage will occur on large and small branches alike when olive trees are exposed to such low temperatures. An entire tree can be killed when exposed to 15-degree temperatures for only a single night.
- While some varieties of olive trees are a bit more cold weather hardy than others, none can withstand freezing temperatures. When exposed to chilly weather, the flavor in the olives or olive oil tends to taste “off” or unpleasant.
Olive Tree Pollination & Fruit
- All olives are wind-pollinated. If you experience wet weather from April through June, the natural pollen cycle the trees need to flourish and produce fruit can be vastly impacted in a negative manner.
- These trees love warm weather! Olive tree flowers bloom best when exposed to approximately 45-degree temperatures as they grow into bloom – depending on the variety being grown.
- Olives will grow best when planted and exposed to moderate to dry conditions during the blooming stage.
- Periods of intense heat during the flower blooming stage may cause poor fruiting for the season.
Fertilizing Olive Trees & pH
- Olive trees typically demand 40 to 100 pounds of nitrogen per acre to grow productively. Legume crops are an excellent companion for olive trees due to the nitrogen they infuse into the soil.
- While a pH level of 6.5 is best for olive trees, they can tolerate pH levels that fluctuate between 5 to even 8.5.
- Highly fertile soil is not recommended due to the overabundant production nature of olive trees.
How to Choose an Olive Tree Variety
When purchasing olive trees, carefully consider the level of cold sensitivity and the speed of maturity. The type of olive oil you want to produce should also be taken into consideration when selecting a variety of olives to cultivate.
While some olive tree varieties are recommended either for table olive or olive oil making, varieties exist that produce fruit that are equally good for both. The maturity of the olives and the growing environment will always influence the taste of oil to varying degrees.
For example, the Olives range in color from the common green to black, with some having a pepper-like pungent smell. Most olive oils are made from a mix of both ripe and green olives where the fruit is harvested from the tree just as they are changing color.
Best Olive Tree Varieties
Olive Harvesting Tips
- Olives are typically ready to harvest from the middle to late October, but some varieties, depending on the growing climate, grow through to the end of the year.
- Hand harvesting is common in all but large orchards. A net is placed on the ground around the base of the olive tree to catch the fruit that falls as the branches are shaken, pulled, or pneumatic rakes are used to remove it.
- The moment olives leave the tree, they begin to deteriorate. Olives that are collected in bins turn into a type of compost that cause “fustiness” to occur, which reduces the quality of olive oil.
How To Make Olive Oil
How to make olive oil is an incredibly simple process that does not necessarily require any expensive mechanical equipment.
1. Wash The Olives
Start by washing approximately five pounds of olives in cool water. You do not have to remove the olive pits, but doing so may reduce the chances of damage to your blender later on in the olive oil-making process.
2. Crush The Olives
Place the olives into a bowl and grind them into a paste with a mill, meat tenderizer, mortar and pestle, or the primitive way with a clean stone. It is the crushing process that releases the oil in the olives. Alternatively, to make the olive oil-making process easier or if you’re planning on making bulk olive oil, get yourself one of these:
3. Add Water To the Mash
With the manual method, place the olive mash or paste into another bowl or blender pitcher – neither should be filled more than three-quarters full. Pour three tablespoons of hot water into the pitcher or bowl for every cup of olive paste. Do NOT use boiling water.
Stir the mixture together to ensure the water is fully infused into the mash. Blend to grind the olive mash down so oil droplets begin to rise to the surface. This process typically takes about 5 minutes. You do not want to blend any longer than necessary because doing so will infuse more oxygen into the mash and decrease the shelf life of the olives.
Stir the mash with a mixing spoon at a rapid clip for a few minutes to help the small droplets of oil fuse together and create larger ones. This forces the pulp in the mash to draw up more oil.
4. Let The Olive Mash Rest and Strain It
Cover the blender, pitcher, or bowl you have poured the olive mash into loosely with a paper towel or dishtowel. Let the mash rest for five but preferably 10 minutes to allow more oil to be drawn up to the surface.
Place cheesecloth into a strainer and pour the olive oil mash into the new bowl. Wrap the top of the cheesecloth over the top of the olive oil paste so that it is completely covered. Wrap a brick or something equally heavy in plastic wrap and place it on top of the olive oil paste.
Place the strainer on top of a large bowl. Press down firmly but gently on the weight. Every 5 minutes for the next half an hour, repeat the brick pressing process.
Remove the strainer containing the paste. Use a baster or syringe to extract the olive oil from the puddle of solids in the bowl. Repeat the brick pressing process as necessary if the olive oil mash looks as if it contains more oil.
How to Store Olive Oil
Store the olive oil in a container in a cool dry place out of direct contact with sunlight. Sunlight will degrade the oil and reduce its shelf life. The DIY olive oil should be used within two to four months of its creation date.
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