Why are the blood oranges on my tree splitting before they are ready to pick?
San Diego County California citrus
Oranges and other thin-skinned citrus splitting prior to maturity is a physiological response to fluctuations in soil moisture. This problem is usually most prevalent in sandy, well-drained soils that do not retain moisture. When a tree experiences dry soil during the fruit enlargement phase, the fruit loses size and elasticity. Subsequent wet periods then can exert excess pressure on the fruit and splitting. This problem can be avoided by avoiding soil drying through regular irrigation throughout the fruit development period. Mulch can also stabilize soil moisture and help prevent soil drying. Provide appropriate mineral nutrition by fertilizing with complete fertilizers that contain micronutrients. Certain micronutrient deficiencies may also be involved with fruit splitting due the role they play in water translocation.