Why do growing oranges split before they are ripe?

Question

I live in the Canary Islands and grow fruit in my yard - i.e. Oranges. They get watered three times a week through an automatic watering system at the rate of 6 liters of water each session. I have been growing Oranges for the past three years - this is the first time they split before they ripen. What is the cause?

Answer 1

From September through November, splitting in navel oranges often occurs on green fruit. The split usually starts at the stylar, or navel, end of the fruit, the weakest point in the rind. The split may be short and shallow or it may be deep and wide, exposing the segments and juice vesicles.

Splits probably occur when water and sugar are transported from the roots of the tree to the ripening fruit, and the rind is unable to expand quickly enough to accommadate the added volume. The rind bursts open under the pressure. Some citrus varieties, especially thin-skinned ones, may be more likely to split than other varieties. Rinds that have been sunburned or otherwise damaged may be less elastic than normal and therefore more apt to split.

Splitting is a long-standing problem in most areas where navel oranges are grown. The number of fruit affected by splitting varies from year to year and from one citrus-growing area to another. In some years, the percentage of split fruit is high; in other years it is negligible. Usually only a small portion of the fruit on each tree is affected.

Although the exact cause is unknown, fruit splitting is likely the result of stress to the tree. SPlitting appears to be most closely related to extreme fluctuations in temperature, humidity, soil moisture, and possibly fertilizer levels, and the disorder is probably caused by a combination of these factors rather than by a single cause. For example, when hot weather is combined with high winds, the tree becomes drought stressed and begins to take water from the fruit, casing the fruit to soften and the leaves to cup. If the tree is then irrigated heavily, the dehydrated fruit swell, causing them to crack. Young trees or dwarf varieties with realitively small or shallow root systems, as well as trees grown in very sandy or porous soils that do not retain moisture well, may be more susceptible to fruit splitting.

Resonable cultural practices to avoid extreme fluctuations in soil moisture and fertilization leverls throughout the growing season may help to minimize fruit split. Trees should be irrigated regularly to assure a continuous supply of soil mositure, especially during hot or windy weather. When hot winds are anticipated, irrigate before the winds begin. After the hot winds subside, irrigate lightly for a few days and then resume a normal irrigation schedule. Instead of a single large application of quick-release fertilizer each year, smaller monthly applications throughout the growing season (Feb-May) may help keep nutrient levels constant. Timed-release fertilizers offer the convenience of supplying nutrients at an even rate over the length of the growing season, but theya re usually more expensive than other fertilizers.

Split oranges are edible, although they are usually not ripe enough to be usable; they break down quickly and eventually drop from the tree. Damaged fruit should be removed and discarded, since they are susceptible to invading organisms that may cause disease such as Alternaria rot. Decaying fruit may also harbor fungi, bacteria, insects, or other unwanted pests.

Answer 2

Fruit with a heavy water content sometimes split when they receive excess water.If you are watering the same way as previous years, and rainfall was heavier this year that could be the problem.