Every gardener has a soft spot for certain flowers, and we in Indoor Garden Nook have a particularly soft spot for gardenias.

Gardenias look like a perfect snowflake, and just like any other flower, they need to be nurtured and loved, which means that they need nourishment in the form of good a fertilizer.

We’re here to offer some excellent fertilizers for your gardenias, and also share a couple of pieces of advice about how to properly fertilize them, how often, and when. Let’s see what’s in store!

Top 8 Fertilizers for Gardenias

After testing more than 20 fertilizers, I’ve came up with the list of 8 that really do great job with gardenias. So, without further ado, here’s the list!


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✓Formulated for acid-loving plants;
✓Strengthens roots;
✓Long-lasting 20lb bag;
✓Versatile 8-4-8 fertilizer. 

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✓Lowers pH of the soil ensure the health of all acid-loving plants
✓0-0-0 fertilizer excellent for gardenias
✓Versatile – works in all types of soil
✓Easy to use

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Nelson Plant Food 

✓Stylish pack easy to use
✓High quality
✓9-13-11 fertilizer perfect for acid-rich soil
✓Great for all acid-loving plants

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✓Excellent for acid-loving plants
✓Starts working immediately after the application
✓Feeds the plants through both leaves and roots

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Jobe's Azalea Spikes

✓Simple to use
✓Continuous supply of nourishment
✓9-8-10 formula
✓Full-season activity

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✓Simple application
✓Perfect for acid-loving plants
✓Price friendly

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EB Stone

✓All organic chemicals
✓Excellent for acid-loving plants
✓Easy to use

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Jobe’s Organics Food    

✓Organic and biodegradable
✓Easily dissolve in water
✓Great for acid-loving plants

1. Sunniland


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Sunniland’s product is designed primarily for feeding gardenias and camellias, but you can also use it for growing other acid-loving plants. It’s safe to use for both indoor and outdoor gardening.

Rich with magnesium and iron, this fertilizer will give your gardenias more beautiful green leaves, stronger roots, and more vibrant color.

As per Sunniland’s recommendation, you should use this fertilizer early in the spring, after the blooming, and then again later in August. That way the soil can reacquire the necessary nutrients it lost after the summer growing season.

Sunniland’s granular fertilizer comes in a 20 lb bag. It’s made to be consistently released, so we strongly advise you to spread it at your gardenias’ base and then water the granules into the soil for maximum effect.


  • It’s acidic and perfect for Gardenias
  • Doesn’t need to be constantly applied
  • Pack last quite long
  • Especially effective on large patches


  • None so far

Bottom line

If you’re tending mostly to acid-loving plants and you’re looking for a long-lasting and efficient fertilizer, Sunniland’s product is just what you need!

2. Bonide


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Due to it being made of aluminum sulfate, Bonide’s product is one of the best fertilizers you can use for your gardenias. This aluminum sulfate-based fertilizer is perfect for gardenias and not only them but for the rest acid-loving plants, since it causes the soil pH to drop, that way providing almost ideal growing conditions.

Another great feature of this product is its sheer versatility. It is equally effective no matter the type of soil you use to grow your gardenias or azaleas. Whether it’s only one pot or an entire little garden in your back yard, this fertilizer has you covered.

Bonide has included a neat chart where you can see how much of the fertilizer you need to use depending on the type of your soil. Bonide recommends to examine your soil first, then use the appropriate amount of fertilizer as displayed in the chart in order to lower the soil acidity to 5.0, the optimal soil acidity for growing gardenias.


  • Applicable to any type of soil
  • Instruction chart included on the package
  • Applicable to all acid-loving plants
  • Lowers soil pH


  • 4 lb package a bit too small

Bottom Line

Bonide’s little package of wonderfully efficient fertilizer has quite a lot to offer for a reasonable price, so do check out – your gardenias will love it!

3. Nelson Plant Food

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Nelson’s Plant Food is will be of great use not only to your gardenias but also to all similar plants you may be growing. Within the formula of this fertilizer are ingredients that lower the soil pH.

It is also rich with nitrogen and iron, which are some of the most crucial nutrients for every plant, not just the acid-loving ones!

Using this fertilizer will give your gardenias a number of long-lasting benefits: their leaves will be stronger and greener, their roots healthier, and their bloom more beautiful and vibrant.

The manufacturer warns against overusing the fertilizer since it may burn or seriously damage your gardenias. They strongly recommend using it at the beginning of spring, reapplying it once each month until the end of the growing season. You can find it 2, 4, 15, and 20-pound jars, all of them resealable.


  • Formula lowers soil pH
  • Applicable on both acid-poor and acid-rich soil
  • Numerous beneficial effects
  • High-quality package


  • None so far

Bottom Line

Nelson’s Plant Food is an excellent choice for every gardener raising acid-loving plants and has arguably the most stylish package of all the items on our list. Its long-lasting beneficial effects make it more than worth your consideration!

4. Scotts Acid-Loving Plant Food

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Scotts Company Miracle-Gro 30-10-10 fertilizer is yet another fertilizer especially effective when used to feed acid-loving plants, meaning it’s amazing for gardenias. A single one-pound package can cover up to 400 square – a small package with one heck of a punch!

What makes this fertilizer stand out among the competition is its double-feeding feature. This fertilizer does not simply provide nourishment via your plants’ roots, but also through their leaves, thus providing your flowers with richer greenery, stronger roots and more beautiful bloom.

As recommended by the manufacturer, use this product once every week during the blooming season. You can apply it either via sprayer or a watering can. The manufacturer has also included the set of instructions regarding the mixture on the package for optimal results.


  • Double-feeding properties
  • Strong and effective
  • Price-friendly
  • Very versatile and easy to apply


  • None so far

Bottom Line

If you’re looking for a strong yet easy-to-use fertilizer with long-lasting effects and great nourishing capabilities, this product would be an excellent choice for you!

5. Jobe’s Azalea Fertilizer Spikes

Jobe's Azalea Fertilizer SpikesShop on Amazon!

Jobe’s fertilizer spikes are arguably the easiest to use of all the fertilizers on our list. Every spike is already premeasured and perfectly balanced, so it lasts for quite a while, constantly providing the necessary nourishment for your gardenias to flourish.

Due to its premeasured content, you won’t need to worry about making a mess – your plants will get 100% of all the necessary nutrients for them to thrive and grow!

One waterproof, resealable pouch contains ten fertilizer spikes. If necessary, you can buy them in bulks of up to for bags. According to the manufacturer, the most effective way of application is after the bloom, in late spring, for optimal results.


  • Easy to use
  • No run-off or waste
  • Perfectly balanced formula
  • Price-friendly


  • None so far

Bottom Line

Easy to use and amazingly effective, this fertilizer should definitely catch your eye no matter if you’re an indoor or an outdoor gardener!

6. Miracle-Gro Plant Food

Miracle-Gro Plant Food

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Miracle-Gro strikes again with a slightly improved yet equally effective version of their fertilizer for all acid-loving plants such as gardenias. This fertilizer goes straight to do root and immediately starts feeding your plants!

This 30-10-10 fertilizer comes in the easily dissolvable powder form, and you can apply it via watering can or a sprayer. Thoroughly soaking the base of your plants is required for optimal results, and you should repeat the process every 7-14 days.

It’s rich with iron and other nutrients, and it’s perfectly applicable both in indoor and outdoor conditions. However, make sure to follow the instructions, or the fertilizer will seriously damage your plants!


  • Price-friendly
  • Easy to use
  • Starts working almost immediately
  • Great for all acid-loving plants


  • Needs careful application due to strong formula

Bottom Line

If used properly, this fertilizer will suit all your gardening needs and make your plants grow strong and beautiful. An excellent purchase!

7. EB Stone Gardenia Food

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Another organic fertilizer on our list, EB’s 5-5-3 fertilizer is an excellent choice for every gardener. It’s easy to use and apply in both indoor and outdoor conditions, and it’s made out of all-organic chemicals such as bat guano, dried chicken manure, bone meal, and cottonseed meal.

The mixture of these and many other substances enhance the growth of your plants and provide them with great amounts of nourishment. That, in turn, gives plants stronger roots, mover vibrantly green leaves and more beautiful bloom.

The fertilizer is especially effective on already acidic-enough soil, but it works just as well on a low-acidity soil, which is perfect for your acid-loving plants, and due to it being easily dissolvable in water, you won’t need about runoffs or other mess in general.


  • 100% organic chemicals
  • Easy to apply
  • Quickly dissolves in water
  • Perfectly safe to use


  • None so far

Bottom Line

Easy to use an organic fertilizer is always a good idea for a number of reasons, especially in terms of safety and efficiency. This makes this fertilizer and excellent investment!

8. Jobe’s Organics Food

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Yet another great product from Jobe’s proverbial kitchen, this organic 6-1-1 fertilizer is excellent for all plants that require higher-than-normal levels of acidity in the soil, your gardenias being among them. It strengthens your plants, provides all the necessary nutrients, and reduces the risk of diseases.

This fertilizer is easily dissolved in water due to its all-organic chemicals, so you can apply it either via spray or your common watering can. You can apply it to both soil and the leaves since and your plants will be protected and nourished even in periods of drought.

The manufacturer has included am instruction manual on the side of the package. Depending of the size of the bush, you can use a tablespoon per gallon and apply the fertilizer every 7-14 days for a small bush, or 14-28 days for a larger bush.


  • Organic fertilizer
  • No synthetic chemicals
  • Safe for the environment
  • Safe to use around kids and animals


  • None so far

Bottom Line

If you’re looking for an eco-friendly organic fertilizer that’s easy to apply and perfectly safe, look no further than Jobe’s!

When Is the Right Time to Fertilize Gardenias?

In general terms, you should apply the fertilizer for your gardenias in spring, summer, and fall, with a pause during winter. Being evergreen plants, your gardenias should grow properly if tended in the right way.

If you’re just about to plant your very first batch of gardenias, it would be smart to test your soil first. Depending on the results, you may need to alter your soil’s pH in order to provide your plants with the optimal growing conditions.

More experienced gardeners advise examining the soil pH at least once a month. If the value is higher than 4.5 and lower than 5.5, you’re all set. If not, you may need to do something about it. Gardenias love high acidity, so your soil has to have the necessary acidity level for it to thrive.

It would also be wise to check the pH value every few weeks after the application of the fertilizer. If the value is not in the prescribed parameters, you should reapply the fertilizer, but it’s always best to simply abide by the manufacturer’s instructions.

The acidity of the soil depends on various reasons: your general location, the position of your plants (how close to the road are they, etc.), this all can influence your soil’s pH. For instance, soil close to the road is more alkaline in nature, so it requires more frequent fertilization.

Water also has some impact on the overall pH value of your soil. There are subtle differences between water from the tap and the water from a hose, and then there’s rain, which can further alter the acidity of your soil.

That’s why you should check your soil’s pH value relatively frequently in order to keep tabs on it and make all the necessary adjustments whenever the pH level is above or under the prescribed level.

How to Properly Fertilize Gardenias

How to Properly Fertilize Gardenias

There are several ways of fertilizing your gardenias depending on the sort of fertilizer you use. We strongly suggest you duly follow the manufacturers’ instructions in order to avoid any potential issues stemming from overusing the fertilizer. That being said, here are some general pointers for you to follow.

Liquid Fertilizer

In the case of liquid fertilizers, following the instructions on the pack is the key. Some more experienced gardeners advise the use of only half of the prescribed dosage in case you’re using a strong fertilizer.

A common mistake of all novice gardeners is the overuse of the fertilizer, which can have devastating consequences for their plants. They can sometimes use more than one full dose of a strong fertilizer hoping that that way they’d boost their plants’ growth, but such actions only result in the death of the plant.

This is why testing your soil’s pH matters so much. Depending on the pH level, you may decide to use a weaker fertilizer or half the dosage of a stronger one. This makes it much easier to choose the proper fertilizer which best suits your gardening needs.

Liquid fertilizers can be applied in more ways than one.

For example, if your goal is to cover a large surface as efficiently and as quickly as possible, the sprayer is the way to go. If you have a small garden or if you only keep potted plants, a common watering can or any other container will serve you well. Choose a container large enough for you to safely mix the fertilizer.

Bear in mind: some liquid fertilizers can be safely applied on both the foliage and the base of your gardenias, while others are meant for root-only application, so please follow the instructions to avoid the consequences of misapplication!

As for the number of times you need to use the fertilizer, it depends on the soil pH and the strength of the fertilizer itself. Usually, once or twice a month should do the trick, but in cases of pH not being in the prescribed range, another dose of the fertilizer may be necessary.

This may seem a bit intimidating for beginner gardeners, but don’t worry; just follow the instructions and all will be well!

Granular Fertilizers

Granular fertilizers are fertilizers specifically designed to work for long periods of time. These slow-releasing fertilizers have a special slowly-deteriorating coating which releases a stable dose of necessary nutrients into the soil until it completely dissolves.

The application of the granulated fertilizers varies. Generally speaking, if your plants are still young, the smartest thing to do is to insert the granules into the soil and then water it for optimal results.

In the case of older, stronger plants, spread the granules at the base of your plants and then water them. Watering after scattering the granules is essential. They are not designed to be dissolved in water before use!

Spike Fertilizers

Just like granules, spike-type fertilizers are also designed to be used for long periods of time and are probably the easiest form of fertilizers to use. All you need to do is to insert them into the soil as close to the roots as possible, and the water the soil generously so the nutrients can be released from the spikes.

All slow-working fertilizers are usually quite strong and full of nutrients necessary for the health of your gardenias, and they make your job much easier since they don’t need to be used as often as some other fertilizers!

Possible Fertilizing Issues

Gardenias require very specific conditions to grow healthy and beautiful, so if something goes wrong, it’s not that easy to discern if the fertilizer issues are to blame. Regularly testing the pH of the soil is the only way to know for sure whether the problem is in the fertilizer or in the soil itself.

Plants can suffer from various issues directly caused by the lack of necessary nutrients, but fertilizers aren’t always to blame for these problems.

Some types of insects can have quite a damaging influence on your plants. For example, the larvae of the black-vine weevil burrow deep among the roots of your plants and tear them apart in the process.

This stunts the growth of the gardenias due to the roots being unable to fully absorb all the nutrients required for them to grow into lush, beautiful flowers.

The salinity of the soil also plays a major role in the welfare of your plants. If the salinity levels of the soil are high, the reasons for that might be either you overusing your fertilizer or the very nature of the soil itself. High salinity levels of your soil do not benefit your gardenias at all.

Gardenias prefer the soil they grow from to be properly wet, but they won’t be able to properly develop if you overdo it with the watering. If the soil is too wet, the leaves will go from green to yellow and start falling off. If the soil is too dry, the leaves will turn brown, as if they’re burnt under the strong sun.

Determining the right reason for your gardenias not growing to their full potential is not always an easy thing to do, so the only way to know for sure if the problem is the lack of fertilizer, or overabundance of fertilizer, or something else entirely is to have your soil examined.

The Best Fertilizer for Gardenias (in General) + our top Choice

As we’ve mentioned earlier, gardenias are acid-loving plants, so the best fertilizers for them are those specifically designed to nurture acid-loving plants, and also be easily dissolvable in water. They are known as the acid fertilizers.

When the acidity level of the soil higher than 4.5 but lower than 5.5 in ideal conditions, the acid-loving plants will gain all the natural substances they need to thrive and grow.

Many acid fertilizers, as we have seen, lower the pH of the soil. That way, acid-loving plants gain all necessary nutrients they otherwise can’t get in the high-pH soil. Along with the acidity levels, they lower the soil temperature as well, which further benefits the plants such as your gardenias.

In order to retain these beneficial effects, fertilizers should be used roughly every two weeks, depending on the strength of the fertilizer, its form, and the prescribed instructions.

For safety reasons, when applying these fertilizers, always wear protective gear such as glasses, gloves, and long-sleeved clothing. Some of the chemicals may be harmful to humans, so try to avoid them getting in touch with your skin however you can.

Once you’re done with the application of your chosen fertilizer, make sure to thoroughly wash your hands with insecticidal soap.

Depending on your preferences and working conditions, it’s best if you use organic acid fertilizers since they lack the synthetic substances that can harm humans, and are generally easier to dissolve and absorb into the soil.

You can even make your own organic fertilizer! You will need:

  1. A cup of compost tea;
  2. One ounce of molasses, white vinegar, liquid seaweed;
  3. And just combine all that with one gallon of water.

All these ingredients are relatively easy to acquire, and the mixture should give excellent results. And if you don’t want to bother with mixing your own fertilizer, don’t worry: any of the fertilizers we listed earlier will be more than effective.

However, our personal recommendation would Jobe’s Organics (08281), due to its many beneficial effects and the overall safety and ease of use!


Gardenias need very specific conditions in order to thrive. You should pay attention to the pH and the salinity levels of the soil you use carefully chose the appropriate fertilizer, and apply it accordingly.

If you’re just starting to explore the magic of gardening, this may seem a bit intimidating, but it’s really not! If you test your soil regularly and follow the manufacturers’ instructions when applying the fertilizer, everything should be ok.

Just remember this: gardenias do need your love and care, but do not exaggerate – too much fertilizer is murder by kindness!

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