June: the physiological fall, a key turning point in olive cultivation

In June, the olive tree goes through the physiological fall of the fruit, eliminating those that it cannot develop. This natural adjustment allows resources to be concentrated on the most viable fruits. At the same time, the formation of the pit begins and the tree enters a phase of vegetative stop. Thermal stress and lack of water can seriously affect this process. In addition, surveillance on the prays is intensified and foliar treatments are finalised.

During the month of June, the olive tree goes through one of the most decisive stages of its annual cycle: the physiological fall of the fruit, known in the agricultural field as the "fall of San Juan". This natural process consists in the plant, after the curdling of the fruit, makes an internal selection and decides what percentage of the freshly curdled fruits can successfully develop until its maturation. Those fruits that it cannot sustain, either due to water, nutritional or energy limitations, are actively eliminated by the tree.

This phenomenon takes place progressively and usually extends until the end of June or beginning of July, depending on the climatic conditions and the general state of the olive grove. It is a biological strategy of self-regulation that allows the plant to guarantee the development of the most viable fruits, thus ensuring the quality and quantity of the future harvest.

Although in the previous months very positive data were recorded in terms of floral fertility and curd, it is in this phase when the plant begins to adjust its resources. Therefore, the initial estimates should be taken with caution, since after this physiological adjustment we will have a more precise first approximation to the actual production of the year.

Thermal stress and the importance of water

The success of the curd and retention of the fruit at this stage are directly conditioned by factors such as temperature and water availability. If the temperatures are not excessively high and the plant has sufficient reserves of water and nutrients, it will be able to develop a greater number of fruits.

It is essential to remember that the nutrients accumulated in the tree's tissues during previous phases, as well as their level of hydration, determine their ability to sustain the effort involved in the development of the fruits. If the plant perceives that it cannot maintain that physiological effort, it sacrifices part of the fruit to ensure the survival of the rest.

Leaf renewal: leaf molting

Parallel to this process, leaf moulting also occurs in June. Although the olive tree is a species of evergreen, the plant carries out a continuous process of leaf renewal, eliminating those aged, damaged leaves that no longer fulfil a useful function.

The farmer usually observes how certain areas of the tree show yellowish leaves that end up falling. This phenomenon responds to an adaptive strategy: the tree eliminates structures that involve an unnecessary loss of moisture. It must be taken into account that the leaves are the main organ of transpiration of the plant, and in situations of water scarcity, their reduction minimises the loss of water by evaporation.

By reducing the number of inefficient leaves, the tree manages to maintain a balance between perspiration and water absorption from the roots, thus preserving its reserves at a critical moment of the cycle.

Final line of foliar fertilisation

During this month you also enter the final phase in which the plant can effectively take advantage of foliar fertilisation treatments. As the summer stop approaches, the olive tree's metabolism slows down, and with it, the effectiveness of leaf absorption decreases.

This is because the stomas of the leaves, through which the nutrients applied via the leaf penetrate, tend to close to prevent moisture loss. Once closed, the leaf absorption is very limited, which makes this stage the last opportunity of the cycle to perform really effective treatments in this way.

Therefore, the farmer must act with precision and good judgement, applying fertilisers only if they are necessary and prioritising the most favourable climatic conditions (mild temperatures, environmental humidity, etc.) to maximise their effectiveness.