The olive orchard should be plowed or cultivated at least four times during the year, but not to a greater depth than five inches, or the surface roots may be injured.
As soon as the berries are picked which may be in December, January or February, the tree rests. Its labors have not been light in sustaining and nourishing its burden of fruit so long. As soon as it is relieved of its heavy load it begins to recuperate and prepare for the following May when it will blossom again. The orchard should first be pruned and cleaned, and then plowed in order to give the trees the greatest possible assistance.
To keep down the weeds, it will be necessary to plow again before flowering time arrives, but on no account should any cultivation be attempted while the olives are in flower, as the exhalations from the ground, caused by turning over the soil, are very prejudicial to the tree when in this condition. Until the flower has withered and fallen off and the new berry has formed, nothing should be done that would cause any emanations from the soil.
The olive buds first, then flowers, fecundation becomes complete when the pollen comes in contact with the flower eggs, to which it communicates the power of freeing the embryo and transforming itself into seed. To judge whether this has successfully taken place or not, an inspection of the withered blossoms under a tree will demonstrate. If the corolla only has fallen, making a flat, star-shaped flower with a well defined hole in the center, all is well; but if the pistil is attached to it, then fecundation has not taken place and the crop has aborted. This may happen from a variety of causes, and it is the critical period to the olive grower. Too great heat, a late frost, excess of rain, heavy winds, a lack of certain necessary elements in the soil, or an excess of these, may singly or in combination, bring about this untoward result. The first, or too great heat at the time of blossoming, will probably be the source of greatest danger to the California grower. The olive in flower is said to be able to endure a temperature of one hundred and seven
