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The Complete Guide to Orange Tree Fertilizers

If you’re growing an orange tree, you want to give it the best possible care. Generally speaking, the more effort you invest in caring for your tree, the healthier and more productive it will be.

Closeup of mandarins on a tree.

Just as people need nutritious food to be healthy and strong, so does your orange tree. Obviously, your tree’s dietary needs are different than yours. But in the same way you need a good proportion of complex carbohydrates, healthy fats, and complete proteins, a productive orange tree needs fertilizer to be at its best.

So, keep reading this guide on orange tree fertilizer. We’ll provide information on what fertilizers are, how they work, the types of fertilizers, the fertilizer needs that orange trees have, and more.


What Are Fertilizers?

Fertilizer is plant food composed of three essential elements: nitrogen, phosphorous, and potassium. They’re the macronutrients fertilizer supplies to an orange tree and they provide the tree with the energy necessary for growing and fruiting.

What Plant Macronutrients Do

Nitrogen, phosphorous, and potassium have specific roles in a plant’s health and development.

Nitrogen (N)

Nitrogen is essential for the development of the bulk of the aerial zone of the plant, (that is, the part of the plant that is above the ground). This includes the woody growth that comprises the trunk and branches as well as the green development such as the shoots and leaves.

Phosphorous (P)

Phosphorus is essential for the health and development of a plant’s roots. Additionally, phosphorous is vital for the flowering and fruiting processes.

Potassium (K)

Potassium is required for a plant’s general metabolic fortitude. It helps the plant transport water and nutrients as well as withstand unfavorable temperatures, pests, and infections.

Person holding handfuls of granular fertilizer, one form of orange tree fertilizer.

NPK Ratios

When you’re shopping for fertilizer, be sure to read the labeling on the bag. You’ll notice there are three numbers separated by two dashes. For instance, this bag of complete organic fertilizer from Hoss Tools is labeled “5-4-3” in big numbers on the front of the bag.

These numbers are important because they inform you of that particular fertilizer’s NPK ratio, which is the ratio of nitrogen (N), phosphorous (P), and Potassium (K).

Why is the NPK something you need to be aware of? Because different kinds of plants vary in their macronutrient needs. Giving your orange tree fertilizer with the wrong NPK could spell disaster!


On Orange Tree Fertilizers

Like all plants, orange trees have their own optimal nutritional blend.

The best orange tree fertilizers not only have citrus tree-specific NPK ratios, but specialized proportions of every other nutrient as well.

“Orange Tree Fertilizer” or “Citrus Tree Fertilizer”?

All trees require nutrients to grow. They often get enough from the soil they’re planted in, but they do even better when they’re fed fertilizer and cared for. Fruit-bearing trees in particular benefit from fertilizer.

Citrus trees are heavy feeders, even compared to other kinds of fruit-bearing trees. They require a lot of nutritional supplementation so you’ll want a fertilizer tailored for those kinds of trees.

Fortunately, you aren’t strictly limited to products labeled as orange tree fertilizers. From lemons to grapefruit to blood oranges, any citrus trees will do just fine with a basic citrus tree fertilizer.

The Unique Nutritional Needs of Citrus Trees

a potted orange tree

Again, citrus trees require a lot of nutrients. Beyond sheer quantity, it’s important to pay attention to the proportions of those nutrients, especially nitrogen.

Nitrogen is vital for producing large, healthy fruit in these trees.

Citrus trees direct a high amount of energy into producing fruit yields. You want to ensure that the fertilizer you’re giving your tree maximally enables it to do that.

Look for an NPK ratio that emphasizes nitrogen – somewhere in the range of a 6-3-3 should be ideal. Roughly half of the macro-nutritional makeup of the fertilizer should be nitrogen.

The phosphorous and potassium should be in equal proportion with each other.

Read the label to make sure your fertilizer has plenty of micronutrients like iron, manganese, magnesium, copper, zinc, and boron.

What is the Optimal Orange Tree Fertilizer?

There are many excellent orange tree fertilizers on the market. To find some of the best ones, check out our guide on the Best Orange Tree Fertilizers.


How Fertilizers Work

Essentially, all fertilizers work by mixing with and enriching the soil. When a plant’s root system draws up nutrients from the soil, the added nutrients of the fertilizer are there for the plant’s usage.

There are differences between different kinds of fertilizers, but those differences are primarily in how quickly the fertilizer releases its nutrients.

For example, granular fertilizers are likely going to be slow-release while liquid or water-soluble fertilizers are typically fast-release varieties.


Applying Orange Tree Fertilizer

Because different fertilizers and situations call for specific fertilizing approaches, always follow the directions given on the label.

Person holding handful of granular fertilizer mix.

How Much to Apply

Amounts For First-Year Trees

For young trees in their first year, apply a half to a two-thirds cup of the orange tree fertilizer at the start of the growing season.

The start of the growing season depends on where you are, but if you are in a climate that can support orange trees, this generally means February.

Keep applying another half cup every six weeks through October.

Amounts For Second-Year Trees

In the tree’s second year, double the amount. Begin applying it at the start of the growing season and reapply it every seven weeks.

Amounts For Third-Year Trees

In the third year, double it again and begin applying at the start of the growing season. Reapply every nine weeks.

Amounts For Trees Older Than Three Years

For mature trees, or trees past their third year, a rule-of-thumb is to use roughly a pound of fertilizer per year the tree has aged.

A backyard orange tree.

When to Apply

When you fertilize your orange tree depends on several factors such as what kind of fertilizer you’re using, (fast vs. slow release), how old your tree is, whether it’s in a pot or in the ground, and how healthy it is.

Apply the proper amount of fertilizer three times a year. Apply first at the beginning of the growing season, then in either April or May, and then once more in September or October.

How to Apply

Applying orange tree fertilizer to the soil around your tree is very simple and the bag will probably have instructions to follow. Best practices are as follows:

If you’re applying the orange tree fertilizer to a potted tree, simply mix the fertilizer into the top layer of soil all around the tree in a ring. Be careful to not let the fertilizer touch the base of the trunk.

For older or larger trees planted in the ground, do the same thing in a wider radius around the trunk. The fertilizer should be spread as far out as the canopy of the tree extends.

After fertilizing, water the soil well. This will help the fertilizer to start breaking down so that the tree can absorb it through the root system.


Common Orange Tree Fertilizer Mistakes

Person spreading granular fertiiizer around a tree.

Not Applying Enough Fertilizer

If you’ve gone through the trouble of finding and purchasing orange tree fertilizer for your tree, you should use it.

Not applying enough fertilizer means your tree will grow and produce fruit at a much lower rate than if it were receiving the proper nutrition.

Applying Too Much Fertilizer

On the other hand, applying too much orange tree fertilizer can have a far more harmful effect.

Rather than helping the tree to grow, applying too much fertilizer may stunt your tree’s growth, injure the root system, make the tree less robust, and cause overall damage to its health.

Over-fertilizing can also invite problems with infections and pests.

Additionally, using too much of your orange tree fertilizer can have a negative environmental impact. Runoff of fertilizer can toxify water and even poison wildlife.

Applying Fertilizer Inappropriately

Applying fertilizer to your orange tree incorrectly can be harmful and it’s a very easy mistake to make. Be sure to read the label carefully to ensure you’re following the directions.

It’s very important to know what kind of fertilizer you’re using. An organic fertilizer will likely need to be applied differently than a synthetic fertilizer, a granular will need to be applied differently than liquid, and so on.


Healthy Trees Produce Delicious Fruit

Mandarin oranges on a tree in sunlight.

With the proper orange tree fertilizer, your orange tree will be stronger, healthier, and more productive than ever! Give your orange tree the nutrition it deserves, and it will reward you with abundant, sweet, juicy fruits.

At Minneopa Orchards, fruit trees are our specialty. We have so much to share on the topic in the form of articles and posts. Be sure to visit our Orange Trees page for more information on different orange varieties, as well as helpful growing and care guides.