The development of an olive is marked by three perfectly sequenced phenological phases; in each of them, the fruit builds a distinct resource: first volume, then structure, and finally oil. We are currently in Phase 2, the lignification of the pit. This is a key moment in agronomic management when the goal is to produce maximum quality extra virgin olive oil. Supported by our agronomic experience and current scientific research, this article explores what is happening today in olive groves and explains the biological sequence that defines every great extra virgin olive oil.
Phase 1: Rapid Cell Growth (Division and Expansion)
When? Late May to late June, in Mediterranean olive groves. After pollination and the formation of the first fruits, the olive begins its first growth spurt. During the next five to six weeks, the fruit's mission is simple: multiply cells and expand them. Up to 80% of the cells that will house oil are formed during this brief window. New cells appear while existing ones fill with water and sugars, allowing the olive to double its diameter in just one month. The pit remains soft, forming but not yet lignified. What will you not yet find? Oil. Lipid bodies only appear when the pit hardens, so oil content in Phase 1 is practically zero. Why is this phase crucial? Think of each new cell as a "tank" that will later be filled with oil. If its production is limited now by heat, water stress, or lack of nutrients, the fruit will not be able to compensate later, even if conditions improve. Indicators in the field:
- 10 days after fruit set: olives look like small green pearls, still translucent.
- ≤30 days after fruit set: diameter reaches ~1 cm; the growth curve levels off. If the pit resists gentle pressure, Phase 1 ends and Phase 2 begins.
In short, Phase 1 focuses on building capacity. The tree defines the cellular architecture that will contain the oil, aromas, and antioxidants that give extra virgin olive oil its value.
Phase 2: Pit Lignification (Endocarp)
When? Early July to early August, depending on variety and climate. After the first growth spurt, the olive pauses to build its "armor." During Phase 2, the endocarp deposits lignin and becomes the rigid pit that will protect the seed.
- Lignin formation: cells stop dividing and concentrate lignin in their walls, turning a flexible tissue into hard stone.
- Slowdown in growth: resources are diverted to lignification, temporarily halting mesocarp expansion.
- Physiological turning point: once lignification is complete, biochemical signals trigger oil synthesis.
Why is it important? The completion of lignification marks the actual beginning of oil accumulation. In Mediterranean varieties, it is usually completed 80 to 90 days after flowering: mid-July for Arbequina and late July-August for Lecciana or Koroneiki.
Phase 3: Maturation and Oil Accumulation (Lipogenesis)
When? Early August to late October, depending on variety and altitude. In Phase 3, the olive resumes its growth in diameter, but the real change is in weight and oil content. Mesocarp cells fill with triglycerides, and the fruit generates phenolic and aromatic compounds that define bitterness, pungency, color, and antioxidant capacity.
- Early harvest: green fruit, intense, herbaceous, bitter, and slightly pungent oils, rich in polyphenols. Highly valued in haute cuisine.
- Late harvest: as it acquires purple tones, the oil is smoother, rounder, and fruitier, with better yield and lower phenol content.
Conclusion
Phase 1 builds the fruit's "cellular stores", Phase 2 hardens the pit and activates metabolic change, and Phase 3 fills each cell with oil and phenolic compounds that determine flavor, color, and shelf life. Interpreting these phases allows harvesting at the optimal moment, when chemistry, aroma, and yield are aligned.
To understand how this entire process translates into the cup, tasting, and cooking, consult our complete guide to extra virgin olive oil. And to learn about the oils born from this process, explore the range of JANIROC estate monovarietals.
Sources:
- Camarero, M. C., et al. (2023). Characterization of transcriptome dynamics during early fruit development in olive. IJMS, 24(2), 961. doi
- Rosati, A., et al. (2023). From flower to fruit: Fruit growth and development in olive — a review. Frontiers in Plant Science, 14. doi
- Gucci, R., et al. (2009). Water deficit-induced changes in mesocarp cellular processes. Tree Physiology, 29(12). doi
- Sánchez-Piñero, M., et al. (2022). Endocarp development study in full irrigated olive orchards. Plants, 11(24). doi