Growing any type of olive tree indoors takes a few considerations before purchasing.
Olive trees require at least six hours of sun per day, so select a window with sun, away from a heat source and not close to the window, especially during the winter months.
During the spring and summer months, the olive tree could be placed outside, always being aware of the temperatures during the evening, especially in the fall. Olive trees do not like temperature below 40 degrees.
The olive tree needs to be self-pollinating if you are growing inside. Use a clay pot because a plastic pot will retain more water which olive trees do not like over watering. Olive trees prefer well-drained soil, even a bit rocky with small pebbles included in the soil.
Some things to consider:
Make sure the olive tree is not ornamental if you would like a harvest and that the olive tree is fruit-bearing or fruit producing.
Dwarf varieties would be a good idea for moving inside and outside.
Select a reputable grower.
Check the different varieties of the olive tree, particular for dwarfs, self-pollinating and cold hardy.
Water as soon as the soil on top is dry, but do not overwater. During winter, the olive tree will receive less water than in the summer.
What type of olive trees to grow – olives to eat or olives to process as oil.
Types of olives
Arbequina Olive – grown for oil, from Spain
Maurino Olive – compact tree from Tuscany, produce eating olives
Mission Olive – dual variety for green and black pickling as well as oil production
Pendolino Olive – pendulous habit from Tuscany, produce eating olives
Leccino Olive – originally from Tuscany, fruit ripens early
Mansanillo Olive – vigorous plant Spanish cultivar, olives for eating
Frantoio Olive – Tuscan style oil, high yield with very fruity oil
There are many other varieties of olives
Harvesting olives for oil:
After the olives are picked and wash, the olives are crushed.
Stir, by crushing and stirring the olives release the liquid/oil.
The crushed olives are processed by using a sieve and a large spoon, called pressing. The remaining liquid is the olive oil. The olive oil will have varying taste. The taste differs due to the type of olives that are grown, the type of habitat and the type of extraction process.
NOTE: Extra virgin olive oil has set rules and must have no more than .8% free acidity, thus the pricing usually tells about the processing of olives.
It takes about 80-100 pounds of olives to make a gallon of olive oil
Harvesting olives for table:
Pick green olives when they are mature but before the olives change colors. This also depends on the variety you have chosen.
Typically all olives begin in the color green, then gradually change various colors to black. Harvest begins when the tree is about five years old, but it can take a seven year old tree to start producing.
All olives on the same tree do not mature at the same rate.
When olives are picked, the olives are made bitter by a compound named oleuropein. The olives need to be cured immediately:
Olives need to be cured in a brine – salt and water, about ¼ cup kosher salt to 4 cups of water. Other flavors can be added such as wine, cider or vinegar.
The olives need to be submerged and covered for one week. Drain the olives and repeat the same brining process for one more week.
The longer the process takes, the less bitter the taste. There are several processes of brining that can be found on the internet or tried at home.
Instead of using salt, just use water to decrease the bitterness of the olives, then store the olives in a brine in the refrigerator.
Olive trees needs a subtropical climate, plant zone 10 and 11. Some varieties are hardy enough for plant zones 8 or 9, which is why the olive trees need to be indoor plants.
For further information, contact our horticulture hotline for your questions on Wednesday and Friday between the hours of 9 a.m. and noon, 315-736-3394 or review the agency website at cceoneida.com.