5 Best Orange Tree Fertilizers (And How To Use Them)

All trees, especially fruit trees such as orange trees, require certain nutrients to grow big and strong. When those nutrients aren’t available, problems can and probably will arise.

While nitrogen is the most important nutrient for orange tree growth, there are other nutrients your orange tree needs to produce amazing fruit.

The best orange tree fertilizer has all of the main components (nitrogen, phosphorus, and potassium) and micronutrients such as zinc and magnesium.

If you’re growing an orange tree, you probably want it to produce lots of tasty fruit which will require specific nutrients. That’s where we come in, to make sure your orange Tree Journey is successful!

What Should Be In An Orange Tree Fertilizer?

Unlike most trees in your yard, your orange tree is going to need a little extra when it comes to fertilizer.

Since your tree is producing oranges, which requires a lot of input from the tree, you need to make sure you’re giving it everything it needs so you end up with some delicious fruit! That means giving it proper nutrients along with full sun. 

Here are the components that should be in any good orange tree fertilizer.  

How Your Orange Tree Uses Nitrogen

Nitrogen is the most important element in fertilizers for orange trees. It is present in every cell of the tree which is why your orange tree will use more nitrogen than anything else. 

Nitrogen is used in making amino acids, proteins, and enzymes within your orange tree. It is required for many key functions of the cells including respiration, cell division, and growth of the tree. 

As important as nitrogen is, without other key nutrients present in the fertilizer you use, nitrogen will not be able to properly function within the tree.

Don’t forget to make sure your fertilizer has the other important nutrients required for optimal orange tree growth as well. 

How Your Orange Tree Uses Phosphorus

Phosphorus, like nitrogen, is present in all of your orange tree’s living tissues. Your orange tree requires phosphorus so it can photosynthesize and transport energy within the tree.

In order for your orange tree to produce and store energy while photosynthesizing, it needs to have enough phosphorus. 

Unlike nitrogen, phosphorus does not leach easily from the soil and therefore isn’t required in as large of quantities as nitrogen. Leaching is the loss of water soluble substances from the upper layers of soil due to precipitation carrying it deeper into the soil.

While phosphorus does not easily leach from soil, it can become less mobile in clay soils with excess iron, aluminum, or calcium. That’s why having properly balanced nutrients present in your soil and fertilizer is so important! 

Proper watering will also prevent leaching. For a detailed guide, read our article on how often you should water your orange tree.

How Your Orange Tree Uses Potassium

Potassium in your fertilizer is critical for fruit development on your orange tree.

If you don’t have enough potassium, your orange tree won’t produce as much fruit. The fruit will be smaller in size, and the overall quality of your fruit will suffer. 

Potassium is necessary for the formation of sugar and starches in your oranges which is why it can significantly impact the flavor and color of your oranges. 

Potassium can significantly limit the function of nitrogen, so you’ll want to make sure you have enough potassium to ensure your orange tree can use nitrogen efficiently. 

How Your Orange Tree Uses Nutrients

Other nutrients which significantly impact your orange tree, and the quality of its fruit, include boron, calcium, sulfur, iron, zinc, copper, magnesium, manganese, molybdenum, and nickel. 

These nutrients are needed in much smaller quantities than nitrogen, phosphorus, and potassium, but are still extremely important especially when it comes to your orange fruit quality.

Some of these nutrients help regulate cell functions while others are important for the development of tasty fruit.

By using a complete fertilizer made for citrus trees, you’ll ensure your orange tree gets all of the nutrients it needs! We’ll cover the details of the best fertilizers for your orange tree below. 

Soil pH Can Impact Fertilizer

Soil pH is just as important as fertilizer when it comes to plant nutrition. The soil pH is measured on a scale of 0 to 14. A pH of 7 is considered neutral while lower numbers are more acidic and higher numbers are more basic. 

All plants have an optimal soil pH range. For orange trees, the soil pH is recommended to be slightly acidic between 5.5 and 6.5. 

If the soil pH is too high (basic) then some nutrients will bind to the soil and not be available for the plant to use. If the soil pH is too low (acidic) then nutrients may be available in excess which can cause nutrient issues as well. 

Now that you know how pH impacts the availability of nutrients to get from the soil to your orange tree, let’s discuss how you can tell if your tree has a nutrient problem.

Are you interested in learning more about soil pH, check out our article on why your trees might actually like acidic soil.

How Can You Tell If Your Orange Tree Has A Nutrient Problem?

As with most things, too much or too little of certain nutrients will cause problems for your citrus tree. Here’s how to spot a nutrient issue with your orange tree so you can address it quickly.

If you’re ever uncertain about what nutrients your orange tree needs, or doesn’t need, you can always have your soil or leaf tissue tested to find out exactly what’s wrong.

The University of California provides a great tool that explains how to collect soil and leaf samples for testing and how to interpret your results.

Nitrogen

A nitrogen deficiency in your orange tree will cause the leaves on the entire tree to turn yellow-green to yellow depending on how extreme the deficiency is. 

There are several other things that can cause orange tree leaves to yellow too. A nitrogen deficiency will cause the entire leaf to turn yellow with no distinctive pattern to the discoloration.

A nitrogen deficiency will lead to slower tree growth, reduced fruit production, and may reduce fruit size. 

Excess nitrogen leads to increased vegetation growth, delays the rate of fruit maturing, may thicken fruit peels and lower fruit sugar content. Excess nitrogen can also lead to a late flush of leaf growth in late fall which will be vulnerable to frost damage. 

Phosphorus

The most obvious symptom of phosphorus deficiency is seen in the orange tree’s fruit. The rind of the fruit will be thicker, the orange will contain less juice, and be more acidic. 

On rare occasions, phosphorus deficiency may cause the leaves to have a dull, bronze appearance, with the oldest leaves being impacted first. 

Excess phosphorus can cause there to be a deficiency in either copper or zinc by limiting their uptake in the orange tree. Excess phosphorus can also impact the fruit, decreasing its size and making the juice more acidic. 

Potassium

Potassium deficiencies in your orange tree can be difficult to detect. It will lead to reduced tree growth and smaller fruits. Rarely, the leaves can develop a yellow-bronze color, especially leaves closest to the fruit. 

The best way to detect a potassium deficiency is with a soil test or leaf tissue test. 

Excess potassium will impact the orange fruit quality, leading to thicker rinds and increasing the amount of acid in the fruit juice. 

Iron

Iron deficiency will also show in the leaves, with the leaf turning a lighter green except for the veins which will remain dark green. The light green will become more yellow if the problem is not addressed. 

Iron deficiencies can also cause new leaves to be smaller and can eventually lead to dieback of the tree. 

Magnesium

Magnesium deficiency will cause symptoms in your orange tree leaves. The damage will start as a yellow-green spot near the base of the leaf on either side of the midrib. 

The area will become larger and more yellow in color, ultimately turning the entire leaf yellow except for the tip of the leaf and an inverted v-shaped area near the base of the leaf.

Manganese

A manganese deficiency will turn the leaves a light green color except for the areas around the mid-rib and the larger leaf veins which will remain dark green. The light green areas will eventually turn a yellow-bronze color as the deficiency becomes severe. 

Zinc

Zinc deficiency will make small yellow blotches appear between the dark green veins on the leaf. 

If the deficiency is severe, the leaves will become increasingly yellow with the exception of the dark green veins. In the most extreme cases, the leaves can also become smaller and have a more narrow tip. 

Now that you know what your orange tree may look like if it has too much or too little of certain nutrients, let’s discuss the 5 best fertilizers for your orange tree!

1. Granular Fertilizers Are A Common Choice

Granular fertilizers are probably the most common type of fertilizer that most homeowners use for lawns, flowers, and gardens.

It is easy to apply and comes in all sorts of formulations at your local hardware or gardening center. 

Granular fertilizers can either be quick-release or slow-release. For your orange tree, we recommend using a slow-release fertilizer so that your tree has time to use all of the nutrients.

With a quick-release fertilizer, you’ll have to reapply it more often and some of it may wash out of the root zone before your orange tree can actually use it. 

Whichever formulation of granular fertilizer you use, make sure it is a complete fertilizer.

Complete fertilizers have the standard nutrients (nitrogen, phosphorus, and potassium) but also have micronutrients such as magnesium and iron as well. 

Below is a table showing how many pounds of nitrogen the University of Florida recommends for orange trees per year based on their age. They recommend splitting up the total nitrogen needed per year into several different applications throughout the year based on the tree’s age as shown in row 2. 

The table also provides examples of how many pounds of three common fertilizers (6-6-6, 8-8-8, 10-10-10) you should use per application to meet the overall nitrogen requirements. 

Age of Tree	1	2	3	4	5+
# of applications per year	6	5	4	3	3
Pounds of Nitrogen per Year	0.15 – 0.30	0.30 – 0.60	0.45 – 0.90	0.80 – 1.0	1.1 – 1.4
Pounds of 6-6-6 per application	0.4 – 0.8	1.0 – 2.0	1.9 – 3.8	4.4 – 5.6	6.1- 7.8
Pounds of 8-8-8 per application	0.3 – 0.6	0.8 – 1.5	1.4 – 2.8	3.3 – 4.2	4.6 – 5.8
Pounds of 10-10-10 per application	0.3 – 0.5	0.6 – 1.2	1.1 – 2.3	2.7 – 3.3	3.7 – 4.7

When using a granular fertilizer, always follow the recommendations for how to apply it, which should be on the back of the bag, and always wear gloves. 

Most granular fertilizers will recommend that you spread the fertilizer around the tree but don’t let the fertilizer touch the trunk of the tree. You should spread the fertilizer evenly from the trunk and 1 foot past the drip line for each year of growth up to 10 feet. 

For example, if you have a 5-year-old tree, you’ll want to spread the fertilizer evenly under the canopy and then another 5 feet past the drip line. 

For best results, once the granular fertilizer is applied, it should be raked into the soil and then watered in.

This Miracle-Gro Shake N’ Feed Citrus Tree Fertilizer eliminates a lot of the measuring and guesswork required for some other granular fertilizers. It feeds for up to three months per application and includes the micronutrients needed for growing healthy orange trees. 

2. Fertilizer Spikes Make It Easy

Fertilizer spikes are probably the easiest form of fertilizer to use. You can simply place them in the ground where they will slowly release fertilizer for a certain amount of time.

However, there are a few drawbacks to using fertilizer spikes for your orange tree. 

Fertilizer spikes are only releasing fertilizer when it rains. If you aren’t getting rain on a regular basis, your tree won’t be getting nutrients on a regular basis and you’ll have to water them manually to get them to work. 

There is also a bit of debate on how far the fertilizer from a spike will spread through the soil. Since most spikes recommend a spacing of 3 feet or more, some growers worry that the fertilizer isn’t being distributed evenly throughout the root system. 

Drawbacks aside, if you don’t have a lot of time to invest in your orange tree, fertilizer spikes are a great option to minimize the amount of effort you’ll have to use when fertilizing your orange tree. 

These Miracle-Gro Fruit & Citrus Plant Food Spikes only have to be placed twice a year! That can be a huge time saver compared to granular fertilizers. 

3. Liquid Fertilizers Are Known For Speed

Liquid fertilizers are another form of fertilizer you should consider for your orange tree. They can be especially useful if you need to get nutrients to your tree quickly. 

Since it is in a liquid form, your tree will have instant access to all the nutrients liquid fertilizer provides! This can be a huge benefit of using a liquid fertilizer if you’re dealing with one of the nutrient deficiencies we mentioned above. 

Since the nutrients from liquid fertilizers are available all at once, this usually means it will get used by the orange tree quicker and will require you to fertilize the tree more often. 

Most liquid fertilizers come in a concentrated form. You’ll have to add plenty of water, according to the directions, before you can apply it to your orange tree.

Make sure to follow the application directions exactly to avoid adding too much fertilizer to your tree at one time. 

If you’re interested in using a liquid fertilizer for your orange tree, EZ-gro Citrus Fertilizer has all of the essential nutrients your orange tree will need. 

4. Organic Fertilizers Cut Out The Synthetics

Organic fertilizers are derived directly from plant or animal sources rather than being produced synthetically.

Granular, spike, and liquid fertilizers are all available in organic forms. There are a couple of benefits to using organic fertilizers. 

By using organic fertilizers, you don’t have to worry about introducing any foreign toxins into the soil.

Using organic fertilizers also protects water sources in your area from any synthetic nutrients leaching out of the soil into the water. Anything that may leach out of organic fertilizers is all-natural and safe. 

Organic fertilizers are especially important if you live where other oranges are grown, like in our article, the 4 most common places where orange trees grow.

Organic fertilizers also tend to break down more slowly in the soil. While they tend to contain lower amounts of nutrients than synthetic fertilizers, you may not have to apply them as frequently because they will last longer in the soil. 

The downside to using organic fertilizers is that they do tend to cost more, and you usually have to apply more to get the same results. 

A great option for a granular organic fertilizer for your orange tree is Dr. Earth’s Organic 9 Fruit Tree Fertilizer. It contains the nutrients your orange tree needs as well as beneficial soil microbes which will improve root health.

5. Foliar Sprays Focus On The Leaves

If you’re noticing a nutrient deficiency in your orange tree, a foliar spray may be the quickest way to resolve it.

Foliar sprays are applied directly to the leaves of your orange tree.

Before attempting a foliar spray, you should consider if your orange tree is too large for you to properly apply it. You need to get good coverage over the entire tree canopy for the best results. If your orange tree is too big, you’ll need to stick to the other fertilizer options we’ve outlined above. 

If your orange tree is suffering from magnesium, manganese, or zinc deficiencies, a foliar spray may be the quickest way to help your tree.

Manganese and zinc are best delivered through foliar sprays in a sulfate form. They should both be applied at a rate of 1 to 2 pounds per acre. 

If you decide to apply a foliar spray to your orange tree, make sure you follow all of the product directions and wear the appropriate protective clothing as recommended by the manufacturer. 

That’s A Wrap!

Providing your orange tree with the proper nutrients is critical to its overall health and production of delicious oranges. However, it’s not as simple as just throwing down a generic fertilizer around your tree. 

You’ll want to make sure you give your orange tree plenty of nitrogen, phosphorus, and potassium, as well as all of the other nutrients we’ve discussed here. 

Remember to check the pH of your soil! If the pH isn’t correct, it won’t matter how good your orange tree fertilizer is. You should take a look at our guide on the best places to plant an orange tree so you can choose a spot with the best soil types!

You can use granular, spike, or liquid fertilizers depending on your preferred method of application and how much time you’re willing to invest.

Either way, knowing what you know now about what nutrients your orange tree needs, you’re sure to have a productive orange tree to enjoy for many years!

References

Obreza, T.A. and Rouse, R.E., 1993. Fertilizer Effects on Early Growth and Yield of Hamlin’ Orange Trees. HortScience, 28(2), pp.111-114.

Obreza, T.A. and Schumann, A., 2010. Keeping water and nutrients in the Florida citrus tree root zone. HortTechnology, 20(1), pp.67-73.

Rasmussen, G.K. and Smith, P.F., 1961. Evaluation of Fertilizer Practices for Young Orange Trees. In Proceedings of the Florida State Horticultural Society (Vol. 74, pp. 90-94).