Your cart
There are no more items in your cart
St. John's Day in El Olivar. What you should know
San Juan is a celebration surrounded by myths and popular beliefs. There is one particular belief that affects us olive lovers: the fall of San Juan. It is commonly known that with the arrival of this celebration on June 24, there is a significant drop in the fruits in the olive groves. But what is the truth behind this? Let’s explain it below
What is the Fall of San Juan in Olive Trees?
The Fall of San Juan refers to the loss of fruits that occurs in olive trees during the month of June.
This process is not a myth; it is a physiological process in which the plant selects and eliminates the fruits it cannot develop, thus preparing the ground for the harvest.
The olive tree evaluates and discards some of the fruits it cannot support, a process that extends until the end of June or early July. This selection period provides an initial glimpse of the actual harvest.
Once the fruits that cannot be sustained have fallen, the process of stone formation begins. This moment is crucial for the plant, as it marks a turning point in the cultivation cycle. When the plant successfully forms the stone within the fruit, the first phase of fruit development will have been completed, leading to the summer vegetative halt.
In short, June is a decisive month for the future olive harvest.
Causes of the Fall of San Juan
The main factors that influence the extent of the Fall of San Juan include climatic conditions, particularly that temperatures are not excessively high and that there is sufficient availability of water. In recent years, Andalusia has faced a shortage of rainfall that is significantly impacting olive harvests. If this situation persists for several consecutive years, it results in reduced oil production.
Another important cause of the Fall of San Juan is the attack of pests, specifically the third generation of the olive moth (prays), which targets the newly formed fruit. The adult moth is a small butterfly that lays its eggs on the freshly formed olives during this period. When the eggs hatch, the tiny larvae burrow into the fruit, where they spend the entire summer feeding on the olive seed within the still undeveloped and soft stone. By the end of summer, the larvae drill through the stone and emerge, causing a significant drop in the olives.
Importance and Implications
As we mentioned earlier, this process is very important because it is when the olive tree discards the fruits that it cannot nourish and retains only those it is capable of supporting, continuing with the following phases like veraison.
It is also a crucial stage for making a more realistic estimation of what the harvest will be like. This has significant repercussions in the oil market, as it is regulated by the law of supply and demand, and the oil production that each harvest offers will be decisive in establishing the price.
This month also sees the leaf drop in the olive grove. Although the olive tree is an evergreen tree, it replaces its leaves when they are damaged, lack nutrients, or are no longer functional. The plant itself sheds the leaves that are no longer useful.
Some leaves turn yellow before falling. In this way, the plant removes the leaves that do not benefit it and reduces moisture loss. It is worth noting that during transpiration, plants generate a flow of moisture from the roots to the upper parts, with the leaves being the primary driver of this process.
When the plant transpires, it loses moisture through the leaves, creating a capillary effect that drives water absorption from the roots and its distribution through the xylem vessels to the leaves. If there is an excess of leaves in situations of water scarcity, this increases moisture loss, so the plant protects itself by eliminating unnecessary leaves.
It is important to point out that the plant has defense mechanisms against high temperatures, not only slowing down its metabolism but also closing the stomata of the leaves to prevent moisture loss. These stomata are the primary organs through which fertilizers applied to the leaves are absorbed, and if they close, foliar fertilization does not occur optimally.