How much sunlight do olive trees need?
Written by
Benjamin Miller
Reviewed by
Prof. Martin Thorne, Ph.D.How to grow olives begins with understanding their appetite for Mediterranean sunshine. These trees require a minimum of 6-8 hours of direct sunlight each day to optimize oil production. I had an Arizona client who did not prune their tree and poorly maintained it. The tree produced little fruit until it was finally moved to a south-facing slope. Sunlight drives photosynthesis, which directly affects fruit sugar levels.
Oil Varieties
- Frantoio: 8+ hours for complex oil flavors
- Leccino: 7 hours minimum, tolerates light shade
- Morning sun reduces fungal risks in humid zones
Table Olives
- Manzanillo: 6 hours sufficient for fleshy fruit
- Mission: Tolerates partial afternoon shade
- Avoid dense foliage blocking sunlight
Growers in the northern regions face difficult situations. For example, my own Michigan client's trees received 4 hours of sunlight during the winter. We installed full-spectrum LEDs that were programmed to be 12-hour cycles and 18" above the trees. We found the trees to produce 60% more flowers than trees grown outdoors in the shaded areas! Just as a suggestion, rotate the potted olives weekly so that they are evenly distributed in receiving light.
Artificial Lighting
- LED grow lights at 6000K temperature
- 14-hour daily cycles during winter
- Adjust height to prevent leaf burn
Site Modifications
- Paint walls white to reflect sunlight
- Prune surrounding trees annually
- Use mirrored surfaces strategically
Leaf coloration gives evidence of light maximization. A deep green color indicates proper exposure. If yellowing occurs, there is too much shade. My Greek mentor recommended that I also examine leaves on the southern-facing side of the tree - if they begin to pale in color, you should move the tree. At the same time, sun-stressed olives will recover faster than light-starved olives. Early morning light is always most important to decrease evaporation and drying of moisture from dew-producing processes.
Sustaining sunlight management over many years will grow a legacy tree. I recently visited a California orchard, where the 50-year-old trees continue to bear over 100 lbs per year, due to the ideal spacing of the tree's canopy. To allow for photosynthesis to continue down to the lower fruiting wood, trim away the upper branches. Your children and grandchildren will be thanking you for the sunlight you harvested today.
Read the full article: How to Grow Olives: Step-by-Step Guide for Home Gardeners
