Got Citrus? Learn How and When to Fertilize

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.

HERE ARE SOME GENERAL GUIDELINES:

- 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.

  1. BJ says

    I have one each fruit bearing Lemon, Lime and Orange trees in LARGE containers. I love my babies and winter in the greenhouse (cold here in Central Texas). Can anyone help with a couple issues:
    1) what is the correct brand/type of fertilizer to use?
    2) My Lime tree started dropping all it leaves last fall, they are now popping back out. I noticed when I moved to the GH there was 2 slugs under my pot. Could this be my issue? If so is there anything I can safely treat the soil with?
    Thanks for any advise!

    • Noelle says

      Hello BJ,

      There is not one ‘right’ fertilizer brand. Just choose one that is specially formulated for citrus and follow the directions for fertilizing citrus in containers. There are also organic citrus fertilizers available, which work well, if you prefer to use organic products.

      Citrus can loose their leaves when moved indoors (not due to the slugs). Please see my response above to Alona for the reason why they lose their leaves and how to prevent it.

      Good Luck!
      Noelle

  2. Alona Adams - Dallas,OR says

    As you can see I live in Oregon (Willamette Valley). I have three lemon tree indoors then put them out during summertime. Every winter, most of the leaves dropped off but never come back so I’m left with bunch of twigs. Should I cut/prune them ? What’s left is one single stalk. Should I cut it all the way back? HELP!!

    • Noelle says

      Hello Alona,

      Unfortunately, this is a common occurrence. The problem is that the leaves of your lemon trees, when they are growing outdoors, are acclimated to high amounts of sunlight. Then you bring the trees indoors and they go into a bit of shock with lower light levels, so they drop their leaves.

      To help avoid this – slowly acclimate your lemon trees by shading them using window screen material 3 weeks before it is time to bring them indoors. Then add another layer of window screen the next week and then the final layer of window screen the last week. This should help your tree’s leaves to gradually acclimate to lower sunlight and help them to keep their leaves.

      Don’t prune the twigs, as long as they are still alive :-)

      Noelle

  3. says

    I have a large dog sharing the yard with my orange tree. I am afraid to put down granular fertilizer for fear my dog will sniff it out and eat it. Is there something safe I can use with my dog in the same yard? The tree is planted in the grass and my dog loves to sniff around in the yard. Is there a liquid fertilizer I can use?

    • Noelle says

      Hello Justene,

      There are liquid fertilizer products for citrus trees, which work very well. In addition to liquid fertilizer, there are also organic citrus fertilizers available. Good Luck :-)

      Noelle

  4. sophie says

    Dear Noelle, One year ago this March, my Father and late Mother’s beautiful southern Texas gardens were devastated by a horrific hail storm. Although their orange tree is going to pull through, it did not bear fruit for the first time in 30 years. As this is not where I grew up but where my parents retired and since my Mother was such a gifted gardener and always had things under control, I never bothered to learn from her. Ditto for my Dad who is lost without her in the garden as he simply followed her directions. Thanks to your “Valentine’s Day, Memorial Day and Labor Day” tip for remembering when to fertilize, I feel like I’m one step closer to properly caring for my Mother’s beloved citrus trees. My concern now is when to prune. Before or after fertilization. There are still dead sections on the outer most parts of the branches which took the full brunt of the hail. We did not prune these as we thought there had been too much trauma to do so immediately and then the temperatures quickly soared into the 100′s where they remained until this past Oct./Nov. only weeks prior to the freezing temp. time frame. So now’s my chance but before or after fertilization and when I do prune, is there a rule of thumb like with roses? At the joint before the joint?…HELP! Thank you so much! Looking forward to your advice!

  5. says

    I have a lemon tree and an orange tree I got from friends. I live in Meadview,AZ. Can I plant these trees in the ground? We do get freezing temperatures during the winter months, down to about 30 degrees. The freezing temperatures only come in a couple days at a time, Thank you for your help :)

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