Navel Oranges Splitting on Tree

Jan 29, 2018

Advice for the Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County

Client's Request:  The photo shows an example of navel oranges that are splitting and falling from our large orange tree.  It's occurring at a rate of about 1 a day.  The oranges are not quite fully ripe; so we would prefer not to have to pick them early.  Have you seen this problem in the area?  Any suggestions?

MGCC Help Desk Response:  Thank you for contacting the UC Master Gardener Program Help Desk with your question about navel orange fruit splitting.

Splitting citrus fruit is a common problem, especially with navel oranges. The following link ( is a short 1-1/2 page informative UC document which describes the condition, along with suggestions for resolution. Very briefly, fruit splitting is likely the result of stress to the tree, and is probably related to extreme fluctuations in temperature, humidity, soil moisture, and possibly fertilizer levels. The disorder is often caused by a combination of these factors rather than by a single cause.

Avoiding fluctuations in soil moisture (suggest adding mulch under the tree and consistent and ample water, especially during heat spells) as well as fertilizer levels throughout the growing season may help to minimize fruit split.

I hope this is helpful, please contact us again with any further questions.

Help Desk of the UC Master Gardener Program of Contra Costa County (MCW)

Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone:  (925)646-6586, email:, or on the web at  MGCC Blogs can be found at You can also subscribe to the Blog  (//

By Steve I Morse
Author - Contra Costa County Master Gardener