Got Citrus? Learn How and When to Fertilize

Updated: Jan. 27, 2023

Every year, it never ceases to surprise me that winter is a busy season when you have citrus trees growing in your garden.

Growing up in Southern California, we always had lemon and orange trees in our backyard.  Later, after moving to Arizona, our first home had a huge grapefruit tree along with a orange tree.  In our current home, I have a young orange tree that is growing nicely.

Orange Tree

This time of year most citrus fruit is ripe for eating.  Often, your citrus tree gives you more fruit than you can eat, so if you are lucky, your neighbors are most likely generous with sharing their bounty.  Between my mother’s lemon tree, our friend’s blood orange tree and our neighbor’s grapefruit – we have a lot of citrus in our kitchen right now.  Thankfully, we all love to eat it.  (The only problem with enjoying a bounty of citrus in winter is that you get spoiled.  Later this summer, it will kill me to have to pay up to a $1 per lemon at the grocery store when all our fruit is gone 😉

If you have citrus trees, you want them to be healthy so that they bear delicious fruit.  In order to achieve this, a regular fertilization program is needed.

Lemon Tree

Citrus need to be fertilized 3 times a year with the most important nutrient for citrus being nitrogen.  Other nutrients needed by citrus trees include iron, zinc and manganese which are all micro-nutrients.

Manganese Deficiency
Nitrogen Deficiency

The best and easiest way to get these nutrients to citrus trees is to use a fertilizer specially formulated for citrus, which should contain all these nutrients.

Because citrus need to be fertilized 3 times a year – the timing of when you apply fertilizer is important.  The first application is in the winter, the second in late spring and the last in late summer. Sometimes, it can be hard to remember when to fertilize, but there is an easy way to remember…

**Fertilize your citrus trees on or around VALENTINE’S DAY, MEMORIAL DAY and LABOR DAY.**

Grapefruit Tree

How you fertilize your citrus trees is as important as when you fertilize.


– Fertilizer should not be applied to newly planted trees – wait until they have been in the ground for 1 year.

– Water the soil around the tree before and after you apply fertilizer.

– Follow the directions on the fertilizer bag. Be sure that you divide by 3 the annual amount of fertilizer needed by your tree – do not apply all at once!

– When in doubt, apply slightly less fertilizer then you think you need. You don’t want to over-fertilize and end up with fertilizer burn. Smaller trees require less fertilizer than larger trees.

– Apply granular fertilizer around the perimeter of the tree, extending just past the drip line. Rake into the top few inches of soil.

– For mature Grapefruit trees, (over 6 years old), apply only 1/2 the amount of fertilizer recommended on the fertilizer label because high amounts of nitrogen promote a thick rind (peel).

Kumquat Tree

If you choose to use only organic fertilizer for your citrus, there are some organic products available or you can use composted cow manure, working it into the top few inches of soil and watering it in afterwards.

For more detailed information on how to fertilize, including how much nitrogen to apply, check out this helpful link.