Olives generally take longer to come into bearing than other fruit trees although this is dependent on cultivar, climate and cultural practices.
The olive is a day-neutral, which implies that day length is not stimulus for flower initiation. Optimum chilling temperatures are required for floral development. There is now evidence however, that floral induction can already begin in summer at the time of pit-hardening and is usually already accomplished by mid-autumn, although this depends on the bearing conditions of the tree and type of shoot.
Some factors other than temperature, such as the presence of fruit with seeds, have a negative effect on the following season’s flowering, while the presence of the sufficient healthy leaves is vital for reproductive development. The temperature requirements are complex, with lower temperatures being necessary early in winter and slightly higher temperatures later.
A large number of small, white flowers open over a period of about three weeks in mid to late spring a day later it turns brownish before dropping off. Only about one percent of the flowers setting fruit is enough for a heavy crop. The olive is wind pollinated.
The first 42 days after full bloom is a critical period during which active vegetative growth takes place. Normally olive fruit mature, reaching maximum mass and oil content, about four to six months after blossoming, but can hang on the tree for a considerably longer time. Fruit change from green to a straw-yellow in colour, then on ripening become dark red to black, or even white, depending on the cultivar. The heavier the crop the later it is harvested, the more severe is the effect of reducing the following season’s crop.
- Olive Production in South Africa. (A Handbook for Olive Growers), by Carlo Costa.