Spring:
In spring, the olive trees start to blossom after a long pause during the cold months of winter. The soil around the trees must be fertilized and tilled to improve storage of water near the roots. The trees must also be pruned at this time. The reason for pruning is to help increase olive productivity by promoting even, well-balanced growth throughout the year. The spring fertilizing provides minerals and other nutritional elements necessary for blossoming. It is estimated that for every 100 pounds of olives removed from the soil, an average of 409 g (14.3 oz) of nitrogen, 91 g (3.2 oz) of phosphoric dioxide and 45 g (1.6 oz) of potassium are displaced. Since olive quality and quantity are dependent on optimum fertilization, it is critical that cultivators replenish the soil in the Spring. An old and effective treatment involves the use of organic fertilizers (dung, green fertilizer, etc.) that can supply nitrogen, phosphorus, potassium and many other microelements.

Summer: Olive trees can survive in a dry climate. In fact, a great number of trees (especially those in the mountains) are not watered during the summer months because water is not available. Conversely, olive trees that are located on flat land nearer the sea are more dependent on water, because it is essential at certain times of their vegetative cycle. Flat-land olive trees are watered every 2-3 weeks during the summer months when the olive fruit is in its early stages of growth and the pits hardening. Olive fruit continues to grow until the green colour of the skin fades and reddish spots appear. Any lack of water during this stage can cause olives to be stunted and smaller, with lower oil content. And, the lack of water can also cause olives to fall from the trees.
During the summer months, improperly nurtured olives can be damaged by exposure to harsh weather, disease and parasites. The Olive Fly (Dacus Olei) is the most feared enemy of olive tree growers and harvesters. Depending on summer conditions, this insect can destroy entire crops. The Olive Fly is found in most olive-producing regions throughout the world. Its larvae can have a devastating impact on crops; causing premature olive fruit drop which can greatly diminish the cultivators yield, and undermine months of hard work and planning. Any level of infestation will seriously affect oil volume – including altering oil colour and increasing its acidity. To combat infestations, cultivators use fly antiparasitics, poisoned bait and certain parasites that attack olive fly larvae during summer. Despite the threat of the fly, olive farmers never use pesticides. These poisons have been banned for decades.
Autumn: At this time, olives grow ripe and lose the identifiable green colouring. This colour change results from increased oil content and decreases water content.