3 Best Lemon Tree Fertilizers (And How To Use Them)

Lemon trees are an amazing addition to any yard where there’s plenty of sunshine and warm weather. Those fortunate enough to live where lemon trees grow may be surprised to learn that lemon trees need more than just sunshine and water. Lemon trees benefit from fertilizer, too!

The best lemon tree fertilizers include citrus tree fertilizers, ammonium sulfate, and monoammonium phosphate. Lemon trees should be fertilized three times per year to produce the best fruit and keep the tree healthy and growing.

Below, we’ll go over the BEST lemon tree fertilizers, how to use them, and when to apply them to make sure your lemon tree thrives.

What Is Fertilizer For Lemon Trees?

Some trees and plants do just fine with the nutrients from the soil. Others, like lemon trees, are considered heavy feeders and need a boost of fertilizer to grow properly.

Fertilizers are commonly called ‘food’ for plants, but this isn’t really the case. Plants produce food for themselves through photosynthesis. 

According to the University of Minnesota, fertilizers aid the plant in promoting new leaves, buds, roots, flowers, and fruit.

But not just any fertilizer will work for every plant. Some benefit from higher nitrogen content while others need more phosphorous or potassium. It all depends on what kind of plant is growing and the soil it is growing in.

Lemon trees have a fairly common timeline of growth, however fertilizer can easily speak up this timeline!

The Best Types Of Fertilizer For Lemon Trees

There are TONS of fertilizers out there. How do you know which is the best for your lemon tree? There are 3 main types of fertilizers for lemon trees:

• Ammonium Sulfate Fertilizer
• Ammonium Phosphate Fertilizer
• Citrus Tree Fertilizer

Each fertilizer has advantages and disadvantages when it comes to providing your lemon tree with nutrients.

Ammonium Sulfate Fertilizer

Ammonium sulfate fertilizers aren’t the most popular fertilizer. According to Oklahoma State University, it represents only 2% of the fertilizers used in the United States, though it was one of the most widely used back in the day. 

The nitrogen content of ammonium sulfate fertilizers is higher than phosphorous and potassium. It contains an NPK ratio of 21-0-0. 

(NPK = the percentage of nitrogen, phosphorous, and potassium, respectively). 

Ammonium sulfate fertilizers also have a significant source of sulfur, which is one of the 17 elements necessary for lemon tree survival.

So, when should you use ammonium sulfate compared with other fertilizers? The best time to use ammonium sulfate is if your soil lacks nitrogen and sulfur, or if you need to bring down the PH of the soil.

Lemon trees prefer slightly acidic soils, so if you perform a soil test and find that the PH is too high (basic), then you can use ammonium sulfate to lower the PH.

Ammonium Phosphate Fertilizer

Ammonium phosphate fertilizers come in the form of monoammonium phosphate. They contain a good source of both nitrogen and phosphorous.

The percentages may vary depending on how the product is produced, but most of the time the NPK ratio will be around 11-52-0.

Ammonium phosphate and ammonium sulfate fertilizers are both water-soluble, meaning they are released rapidly in the soil and are available right away for lemon trees. 

Fast-release means ammonium phosphate is a great choice for fertilizer if you are seeing signs of nutrient stress in your lemon tree. However, with fast-release fertilizers, there is always the chance for root burn if there are already enough nutrients in the soil.

Signs of root burn include:

• Brown leaf tips
• Reduced growth
• Discolored roots (where visible)

If you have not performed a soil test and aren’t sure of the conditions of your soil, it may be better to go with a citrus food fertilizer that is slow-release.

Citrus Tree Fertilizer

Citrus tree fertilizers come in a variety of NPK ratios and may be water-soluble or slow-release, depending on if the fertilizer is coated or not.

If your lemon tree is exhibiting signs of nutrient stress, you’ll want to look for a water-soluble citrus tree fertilizer. These will give your lemon tree the nutrients it needs right away.

Slow-release fertilizers are better if your tree isn’t stressed and you simply want to provide nutrients for better growth and fruit production. As we said before, lemon trees are heavy feeders and should be fertilized three times per year.

The best citrus tree fertilizers will have an NPK ratio of 6-6-6, 8-8-8, or 10-10-10. They may have 6-3-3 or something similar. Lower percentages are better than high percentages since the fertilizer will be applied multiple times per year.

Citrus tree fertilizers are a little less targeted toward lemon trees specifically. Instead, they target all citrus trees. Even so, they are an effective fertilizer for lemon trees.

How Does Fertilizer Work For Lemon Trees?

Fertilizers will come with instructions on the back that will help guide you in how much to apply and how often.

But how exactly do fertilizers work once applied?

Most of the time, fertilizers will need to be spread over the soil and then worked into it by watering the soil. There are also fertilizer spikes that are driven into the ground and liquid fertilizers.

Once the fertilizers are worked into the soil, the nutrients will be released into the soil and water that is absorbed by the tree’s roots. 

As the roots of the tree absorb the nutrients, they are then processed by the tree through metabolic processes and used wherever they’re needed most.

Lemons are evergreen trees, so they need enough nutrients and energy to support leaf growth and maintenance all year long!

Should You Fertilize Your Lemon Tree?

We’re talking about all these different kinds and types of fertilizers, but do you really need to fertilize your lemon tree?

According to the University of Arizona, lemon trees should be fertilized three times per year. Once in January, once in March, and again in August.

You don’t always have to fertilize your lemon tree. Lemon trees that are recently transplanted or just starting to grow should not be fertilized. Wait until you start to see growth before fertilizing. This can take up to 2 years.

How To Tell If Your Lemon Tree Needs Fertilizer

Your plants have a great way of telling you when they are stressed. Whether that stress is from nutrients, pests, or water is a whole other question.

Using fertilizer on drought-stressed lemon trees can do a lot more harm than good. Fertilizers promote growth, but without water, that growth can put too much stress on the tree.

Signs of drought-stress include furling leaves and a droopy appearance of both the leaves and branches.

There are some instances where fertilizers are necessary. Lemon trees should be fertilized three times per year no matter if there is a deficiency or not. 

In addition to the normal application of fertilizer three times per year, be on the lookout for some of the obvious nutrient deficiency symptoms listed below:

Nutrient	Deficiency Symptoms	Notes
Nitrogen (N)	Yellow leaves, limited growth, limited fruit production.	Yellow leaves may also occur in fall when temperatures cool or if the soil is too wet.
Phosphorus (P)	Thicker rinds on fruit. Fruit juice is highly acidic.	Unusual to have a phosphorous deficiency.
Potassium (K)	Extremely thin rinds. Small fruit.	Lemon trees may exhibit bronze leaves as well.
Magnesium (Mg)	Yellowing of the middle of the leaves. Tips and base will remain green.
Manganese (Mn)	Leaves are banded with dark green.	This issue may resolve itself throughout the season.
Zinc	Yellow leaves but veins will remain green.
Iron	Dark green or yellow veins on leaves.	Iron deficiency can also indicate that the roots are too wet.

Even if you’re not seeing any of these symptoms, you should still fertilize your lemon tree at least three times per year. This will promote new growth, new fruits, and root growth.

According to Purdue University, healthy lemon trees will have dark green leaves with light green undersides. The fruit will be light yellow with a medium to thin rind. 

Your lemon tree should have an annual growth of 6-12 inches. If you’re seeing stunted growth, it is a sign that your lemon tree is unwell.

You can read more about the growth timeline of a lemon tree here.

How Often And How Much Should You Fertilize A Lemon Tree?

We touched on this a bit earlier, but it warrants going over. Over- or under-fertilizing your lemon tree can have negative consequences that will affect your tree’s health and growth.

Once you choose a fertilizer, you should divide a whole year’s worth of fertilizer into thirds. This way, you can apply the equivalent of a full dose of fertilizer spread evenly over three applications.

It’s best to fertilize your lemon tree once in January/February, once in March/April, and again in August/September. 

Once September hits, you’ll want to cease all fertilizing until January. This is when temperatures are coolest, and lemon trees need to conserve their energy to stay alive rather than producing a lot of fruit.

According to Texas A&M University, apply one cup of fertilizer for every year the tree is old. So, a 5-year-old lemon tree needs 5 cups of fertilizer, split into thirds, for the entire year.

3 Best Fertilizers For Lemon Trees

When it comes to lemon trees, you don’t want to skimp out on fertilizing. Lemon trees are heavy feeders that need a nutrient boost to produce plentiful fruit and continue to grow.

An article in the International Journal for Research in Applied Sciences and Biotechnology found that when lemon trees are given fertilizer, they have a larger stem diameter and a higher number of branches and leaves.

Without fertilizer, lemon trees will most likely still survive but they will not grow as quickly and they will not produce as much fruit. 

Below is a table summarizing the 3 best lemon tree fertilizer types, with a few options under each. We’ll go over each one in detail after.

Fertilizer	Type	NPK Ratio	When To Use
Hi-Yield’s Ammonium Sulfate	Ammonium Sulfate	21-0-0, 22% sulfur	Good source of nitrogen. Best used when soil PH needs to be reduced due to sulfur content.
Greenway Biotech Ammonium Sulfate	Ammonium Sulfate	21-0-0, 24% sulfur	Slightly higher sulfur concentration and larger bag.
Greenway Biotech Monoammonium Phosphate	Ammonium Phosphate	12-61-0	Great for foliar application. Fixes nutrient deficiencies quickly.
Miracle-Gro Shake ‘N Feed Citrus	Citrus Tree Fertilizer	8-2-10	Great for an all-around lemon tree fertilizer. Good for when you don’t know the nutrient content of your soil.
Miracle-Gro Fruit and Citrus Spikes	Citrus Tree Fertilizer	15-5-10	Good all-around fertilizer. Only needs to be applied two times per year. Slightly more difficult than granule fertilizers – must be hammered into soil.

The Best Ammonium Sulfate Fertilizers For Your Lemon Tree

As we mentioned before, ammonium sulfate may not be used as often today as it was back then, but it’s an excellent source of nitrogen and sulfur for lemon trees.

Hi-Yield’s Ammonium Sulfate comes in a 4-pound bag and has an NPK ratio of 21-0-0. It contains 22% sulfur as well. This product comes in the form of course crystals of varying sizes.

The instructions on the bag indicate to use ½ pound per inch of trunk diameter, which is good to go by if you’re not sure of your lemon tree’s age. If you do know its age, you can use the 1 cup per year rule we mentioned above.

For this product and all ammonium sulfate fertilizers, you’ll want to water the soil immediately after spreading it around your lemon tree. If not, the ammonium may react with the air and instead of your nutrients going into the ground, they float away with the wind.

This type of fertilizer is a good choice if the PH in your soil is on the high end. The sulfur in the fertilizer will lower the soil’s PH. This is also an excellent source of nitrogen to help your lemon tree produce fruit.

Four pounds should be plenty for a single lemon tree. However, if you have more than 2 or 3, you may want to consider grabbing a bigger bag.

Greenway Biotech’s Ammonium Sulfate comes in a 25-pound bag and has the same NPK ratio as Hi-Yield’s, 21-0-0. However, Greenway contains 24% sulfur, a little higher than Hi-Yield.

The instructions to apply to your lemon tree are the same as Hi-Yield’s – ½ pound per inch of trunk diameter.

The Best Ammonium Phosphate Fertilizers For Your Lemon Tree

Ammonium phosphate fertilizers are straightforward. They contain some nitrogen, a high amount of phosphorous, and little to no potassium.

This type of fertilizer works great on vegetable and fruit plants as it helps promote vegetable and fruit development.

Nitrogen is an essential nutrient for fruit trees, so any fertilizer you use for a lemon tree should contain at least some nitrogen.

Greenway Biotech’s Monoammonium Phosphate 12-61-0 100% Water Soluble fertilizer is a great option. It comes in a 5-pound bag but is available in both smaller and larger batches if needed.

The great thing about Greenway’s fertilizer is that it can be mixed with water to create a foliar fertilizer spray. What this means is you would create a mixture that gets sprayed directly on your lemon tree’s leaves, as opposed to spreading the fertilizer around the soil.

There are TONS of benefits to using a foliar application as opposed to soil fertilizers:

• Corrects nutrient deficiencies quickly: According to the University of Hawaii, fertilizers that are applied directly to the leaves will correct nutrient deficiencies faster than if applied to the roots (soil).
• Less chance of leaching: Applying fertilizer to leaves means the chances of the nutrients leaching into the soil and eventually the water table is far less.
• Requires less fertilizer: When you use a foliar application you do not need as much fertilizer as you would when applying to the soil. 

For example, Greenway Biotech’s fertilizer suggests 2-10 pounds per 1000 square feet for soil application, but just 2-4 tablespoons per gallon of water for foliar application.

There are a few downsides to foliar applications. If it rains immediately after spraying, the plant will not have time to absorb the nutrients. 

On the plus side, this just means the nutrients make their way into the soil and are absorbed more slowly.

Always read the label and directions carefully before use.

The Best Citrus Tree Fertilizers For Your Lemon Tree

Unlike our last two types of fertilizer, citrus tree fertilizers are designed specifically for citrus trees like lemons.

Citrus tree fertilizers are the best choice if you’re not sure what type of soil you have. The nutrient content is typically a small percentage, which means even if those nutrients are present in the soil, the fertilizer is unlikely to burn the roots.

Miracle-Gro tends to be the standard when it comes to citrus tree fertilizer. Miracle Gro’s Shake ‘N Feed Citrus, Avocado, Mango Plant Food is a popular choice, and for good reason.

In addition to an NPK ratio of 8-2-10, it also contains magnesium, sulfur, and iron. These micronutrients are important for lemon tree health and will help in combination with nitrogen, phosphorous, and potassium to produce plentiful fruits and lush green leaves.

It is simple to use and comes with a feeding guide on the back of the container so you can be sure you’re using the right amount for your lemon trees. Simply shake the amount over the soil and water it into the soil after application.

Miracle-Gro suggests applying the fertilizer every 3 months, which is on par with how often you should be fertilizing your lemon tree.

If you still want to stick with Miracle-Gro but would rather not use granules, you can try Miracle-Gro’s Fruit & Citrus Plant Food Spikes.

These are placed into the ground early in the season – for lemon trees, this would be January or February. It is then suggested to apply them again later in the season such as at the beginning of fall.

If you decide to go with fertilizer spikes, here are a few suggestions to make it easier to get them into the ground:

• Apply after a rainfall – the soil will be easier to work if it’s soft and moist.
• Dig with a spade first – this way, you’re not driving your spikes into rocks or roots, which can shatter the spikes.

If your spikes shatter, it’s not the end of the world. Crumble the spike up and spread it around the soil as if it were a granule fertilizer. Be sure to water the spikes after applying.

Always follow the directions on the label before use.

That’s A Wrap!

There’s nothing quite like a fresh glass of lemonade made from your very own lemons. Or maybe a lemon cheesecake, pudding, or meringue pie. Yum!

To stay healthy and continue producing lemons, lemon trees need a little nutrient boost during the growing season. That’s where lemon tree fertilizers come into play.

To recap, the 3 best lemon tree fertilizers include:

• Ammonium Sulfate Fertilizer
• Monoammonium Phosphate Fertilizer
• Citrus Tree Fertilizer

Granule fertilizers should be applied around the dripline of your lemon tree and then watered into the soil. Fertilizer spikes should be driven into soft soil and then watered.

You should fertilize your lemon tree three times per year, or if you use fertilizer spikes, two times per year. Do this, and you’ll have a happy and healthy lemon tree for life!

References

Alila, P., & Srivastava, A. K. (2008). Slow Release Fertilizers and Citrus: Emerging Facts. Agricultural Review, 29(2), 99-107.

Majeed, A. W., & Altaai, A. F. (2022). Response of Lemon Transplants to the Addition of Organic Fertilizer to Withstand Water Stress. International Journal for Research in Applied Sciences and Biotechnology, 9(3). https://www.ijrasb.com/index.php/ijrasb/article/view/375

Morgan, K. T., & Kadyampakeni, D. M. (2020, May 03). Nutrition of Florida Citrus Trees Chapter 6. Fertilizer Sources and Formulations (3rd ed.) [Bulletin SP169 and SL253]. University of Florida.

Zekri, M., & Obreza, T. (2013, July). Calcium (Ca) and Sulfur (S) for Citrus Trees [Bulletin SL382]. University of Florida.