Fertilizing Fruit Trees

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

Client's Request:  We've recently moved into a new home with several fruit trees in the back garden. I would like some advice on what fertilizer is recommended for them. Additionally, one of the trees is a pomegranate, could I use some citrus fertilizer I brought when we moved here. Thanks!

MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Help Desk with your questions about fertilizing fruit trees. 

The first things to consider when deciding on a fertilization program for your fruit trees are their age and your soil type. Trees are typically fertilized one way at planting and at the first year, and differently when aged two years to maturity. Most soils in this area are clay and mineral soils, which are rich in both Potassium and Phosphorus, and generally lacking in Nitrogen. Sandy soils, which would be more common in East CCC, tend to be low in Potassium.

The link below takes you to a free UC publication that will give you specific information on fertilizing fruit trees. It includes information on organic choices, manures, and chemical fertilizers. It also provides information on the specific amounts and timing of fertilizer application.. http://homeorchard.ucanr.edu/The_Big_Picture/Fertilization/.

I have also included a link following to information on general care of fruit trees that you may find helpful:. Fruit trees, nuts, berries, & grapevines.

Your second question was whether you can use citrus fertilizer on your pomegranate tree. Pomegranates prefer a neutral to slightly acidic soil- a pH of 5.5 to 7.0. Citrus prefer a more acidic soil, at a pH of 4.5 to 5.5. Packaged citrus fertilizer mixes will tend to increase the acidity of the soil (i.e. lower the pH). Without knowing the pH of your soil, it is impossible to say whether the citrus fertilizer would be harmful to your pomegranate by changing the soil pH to level that is too acidic. Home soil testing is relatively inexpensive and easy to do. There are a variety of home test kits available at garden centers and plant nurseries. Attached is a document containing information on home soil test kits. If you choose not to test your soil, and you pomegranate tree is healthy and thriving, my suggestion would be to not use the citrus fertilizer. You can use it on your citrus; and citrus usually require routine fertilization during the year. Following is another link- this one gives information on pomegranates. https://www.crfg.org/pubs/ff/pomegranate.html .

I hope you find this information helpful. Please feel free to contact us again if you have further questions or concerns.

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

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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: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/  MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (//ucanr.edu/blogs/CCMGBlog/)