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8 Best Fertilizers for Petunias Right Now

Gardening is no less than a superpower!

Best Fertilizers for Hydrangeas

Be it in a spacious garden or inside a hanging container, growing luscious plants of various kinds is no joke. And there’s no better site than a bunch of healthy plants adorning your favorite space of residence.

Hence, many homeowners choose to grow a heavy flowering plant like petunia that adds to their interior or exterior decor. But doing so is easier said than done, especially if you don’t have the right products handy. And that’s the time when you search for the best fertilizer out there.

Although we may not be physically present to help you grow those flowers, we can certainly assist you in buying the right fertilizer. And for this, we’ve compiled this list of the 9 best fertilizers for petunias. As a bonus, we’ve also included a short buyer’s guide at the end so that you can make the right pick.

Now, let’s cut to the deets!

Best Fertilizers For Petunias

1. Miracle-Gro Shake 'N Feed All-Purpose Plant Food - Best for Easy Application

One of our top recommendations is the Miracle-Gro Shake ‘N Feed All Purpose Plant Food. It contains a host of natural ingredients that are essential for the growth of your petunias. What’s more, it has a simple application process, so you won’t have to spend too much time and energy using it.

Miracle-Gro Shake 'N Feed All Purpose Plant Food, Plant...
  • Full of essential nutrients that help feed and nourish above...
  • Contains vital micronutrients to grow stronger, vibrant and...

Why Did We Like It?

For starters, the positive customer feedback helped us put our faith in this product. It's made of the right mix of vital nutrients that facilitate the growth of stronger, more vibrant, and more productive plants. Additionally, this fertilizer has a healthy amount of other natural ingredients like kelp and earthworm castings to nourish the microbes in the soil.

Since microbes help break down natural nutrients that stimulate root strength and overall development, you also get better water efficiency.

We also liked its jar-shaped packaging, which makes for an easy application. All you have to do is peel off the seal, flip open the stout on the cap, and pour the fertilizer in an even manner. Lightly mix it into the top one to three inches of the soil and water it adequately to start feeding. Reapply every three months. 

Here, be careful not to use more than ½ cup per 10 square feet. Also, it should be applied to dry foliage and shouldn’t be piled against the stem. When applied in the right quantity, its non-burning formula prevents the roots from getting damaged.

Lastly, this fertilizer is available in three sizes and dedicated need variants.

What Could’ve Been Better?

Apart from maintaining the recommended quantity, be sure to water the plants heavily to prevent the slightest risk of burning the roots. That being said, the increased microbe development will ensure optimum water efficiency.


  • Has feather and bone meal
  • The ready-made formula doesn’t need mixing
  • 3 months of feeding time
  • Can be used in ground and containers


  • Needs heavy watering

NPK Ratio: 12-4-8 | Weight: 5 lbs | Fertilizer Type: Granular | Application Method: Shake and feed | Duration of Nutrient Release: Up to 3 months | Organic/Natural: No | Target Plants: All-purpose

2. Osmocote 274850 Smart-Release Plant Food Plus - Best for Gradual Nutrient Release

Next up on my list is the Osmocote 274850 Smart-Release Plant Food. It boasts of a specially formulated design that is meant to gradually release nutrients in the soil. Besides, it works for all plant varieties across varying growing conditions.

Osmocote Smart-Release Plant Food Plus Outdoor & Indoor, 8...
  • OSMOCOTE QUALITY: Osmocote is the original slow-release...
  • OSMOCOTE’S BEST FORMULA: Each homogeneous granule contains...

Why Did We Like It?

The Osmocote 274850 Smart-Release Plant Food contains as many as 11 essential nutrients like boron, copper, iron, manganese, molybdenum, zinc, and others that encourage good foliage and flower growth. Beyond that, it has a balanced 14-14-14 NPK ratio, which is perfect for promoting healthy growth in petunias.

But what got us really interested in this fertilizer are its nutrient-coated granules. Simply put, the nutrients are stuffed inside small granules, which have a semi-permeable resin. This covering allows the water to seep through and dissolve the encapsulated nutrients. 

Using a ‘smart release’ process, the nutrients are slowly released into the soil at changing temperatures. The warmer the temperature (during active growth periods), the more is nutrients released. And the feed time of 6 months means the fertilizer gets plenty of time to promote successful blooms.

Application-wise, use 1 scoopful or 3 tablespoons per 4 square feet. Gently mix into the top three inches of the topsoil and water regularly. Try not to keep the granules in direct contact with the plant as this may cause burns.

What Could’ve Been Better?

We’d have liked this product better if the granules were made from some sort of environment-friendly material. When the nutrients inside get dissolved, the plastic shells remain in the soil, thereby requiring you to clear them manually. This may be considered an environmental hazard by potential buyers.


  • Fortified slow-release formula
  • Ideal for both indoor and outdoor use
  • No-burn guarantee when used as directed
  • Affordable


  • Plastic shells accumulate in the soil

NPK Ratio: 15-9-12 | Weight: 8 lbs | Fertilizer Type: Granular | Application Method: Incorporation into soil | Duration of Nutrient Release: Up to 6 months | Organic/Natural: No | Target Plants: All-purpose

3. Jobe's Organics Container & Bedding Plant Fertilizer Spikes - Best for No-Mess Application

Another one of our top recommendations is this super-affordable pack of fertilizer spikes from the house of Jobe’s. Its all-organic ingredients show visible results in a quick time while being free from harmful side effects. If you’re looking for a no-mess application, then this product is worth considering.

Jobe’s Organics 06128, Fertilizer Spikes, Container &...
  • Organic fertilizer spikes; time release fertilizer;...
  • OMRI listed for organic gardening; certified organic means...

Why Did We Like It?

No surprises here as its spike formulation compelled us to try this fertilizer. The finger-sized ‘bullets’ of fertilizer are made of Jobe’s biozone, which contains the brand’s proprietary microorganism called Archaea. In fact, it’s this ingredient that helps the aggressive breakdown of nutrients for the soil to absorb them better.

Not only that, but it also improves the overall soil condition and keeps pests and diseases at bay during the entire growing season. For best results, it’s advisable to use the fertilizer at the time of planting or early on in the growing season. 

This brings us to its user-friendly ‘in-the-ground’ feeding process that makes it deliver the nutrients to as close to the roots as possible. Simply take the spikes and plant them in the soil without requiring any tool (8 spikes per square foot). This, in turn, saves you from the hassle of mixing the fertilizer in the soil, which can be a little messy at times.

Similar to the Miracle-Gro Shake ‘N Feed All Purpose Plant Food, this one is also available in various measurements and for different plant types. If you want to test the waters, we’d suggest buying a 6 spikes pack.

What Could’ve Been Better?

Unlike the other two fertilizers on this list, the Jobe's Organics Fertilizer Spike doesn’t have a specified feeding time. So, first-time gardeners may find it difficult to calculate the right feeding cycle. We’d suggest using it every three to four months for effective results.


  • OMRI is listed as safe for organic gardening
  • Increases root mass
  • Can be used with moist soil
  • Comes in a resealable package for convenient storage


  • Feeding cycle is not mentioned

NPK Ratio: 3-5-6 | Weight: 0.55 lbs | Fertilizer Type: Spikes | Application Method: Sprinkle around plants | Duration of Nutrient Release: Up to 8 weeks | Organic/Natural: Yes | Target Plants: Container and bedding plants

4. J R Peters Inc 52624 Jacks Classic No.1.5 20-6-22 Petunia Feed

The J R Peters Jacks Classic Petunia Feed is made from a blend of the finest raw materials to give professional-looking results without burning a hole in your pocket. Besides, its water-soluble formula is easy and convenient to use.

J R Peters Inc 52624 Jacks Classic No.1.5 20-6-22 Petunia...
  • Designed for plants that do not take up iron efficiently in...
  • Contains an enhanced micronutrient package that will produce...

Why Did We Like It?

Although the name may tell you otherwise, this plant feed is suitable for any plant that cannot take up iron efficiently through the roots (like calibrachoa, bacopa, fascia, nemesia, and so on). And what makes this possible is the amount of chelated iron, which enables the roots to have better absorption ability.

In addition, it contains several other essential micronutrients like chelated manganese, zinc, and copper, among other things that produce lush green plants in almost any growing condition. We also liked the adequate concentration of nitrogen (20%) and potassium (22%), which are responsible for producing greener leaves and healthier roots, respectively. 

This fertilizer is a water-soluble product, meaning you can use it while watering plants. Just add a tablespoon for each gallon of water and apply once every 7 to 8 days. However, we’d recommend going for a constant feeding program, especially during the initial stages of the plant’s growth.

All in all, the J R Peters Jacks Classic Petunia Feed is a cost-effective fertilizer that promotes the healthy growth of plants within a reasonable time.

What Could’ve Been Better?

It may be helpful to know this product contains less phosphorus (6%) as compared to some other plant feeds in the category. Since phosphorus encourages flowering, you may have to switch to some other fertilizer with high phosphorus content during the blooming season.


  • Especially beneficial for hanging baskets and containers
  • Dissolves easily in hard water
  • Doesn’t clog the root nodules
  • Includes a measurement spoon


  • Low phosphorus content

NPK Ratio: 20-6-22 | Weight: 1.5 lbs | Fertilizer Type: Granular | Application Method: Dissolve in water | Duration of Nutrient Release: Up to 7-10 Days | Organic/Natural: No | Target Plants: Petunias

5. Proven Winners Premium Water Soluble Fertilizer

Almost halfway through the list and we’ve yet another water-soluble fertilizer. This product from the House of Proven Winners is a favorite among professional gardeners. But its affordable price tag and effective formula make it an ideal choice for homeowners alike.

Premium Water Soluble Fertilizer, 2.5 lb. Container
  • Proven Winners water Soluble fertilizer comes in an...
  • 24-12-17 fertilizer blend

Why Did We Like It?

Having tried a water-soluble fertilizer before, we wanted to explore some more products in this category. And honestly, we are quite satisfied with how this Proven Winners Fertilizer performs. Firstly, its fast-acting formula is specifically made to prolong life and improve proliferation in heavy-flowering plants. Upon dissolving, the nutrients quickly break down to provide optimum nutrition to the plant roots.

The 24-12-17 NPK fertilizer blend facilitates a bigger bloom. Moreover, the high concentration of potassium (17%) helps the flowers resist multiple diseases. It’s suitable for use in various settings like hanging baskets, landscape beds, container planters, etc. 

Similar to the Jobe's Organics Fertilizer Spike, this one comes in a convenient resealable container with a carrying handle and measuring scoop. The ideal application is once every one or two weeks or in every third watering, but it’s better to follow the exact measurements, which are clearly mentioned on the container.

What Could’ve Been Better?

We feel that the low amount of phosphate might not do much for root development in a short span. In that sense, you may have to start using it from the early planting stage and continue for a long or add a root development feed.


  • Also suitable for annual
  • Makes flowers resistant to diseases
  • Promotes foliage growth
  • User-friendly packaging


  • Doesn’t have much phosphate

NPK Ratio: 24-12-17 | Weight: 2.5 lbs | Fertilizer Type: Granular | Application Method: Dissolve in water | Duration of Nutrient Release: Up to 7 days | Organic/Natural: No | Target Plants: All-purpose

6. Miracle-Gro 1-Pound 1360011 Bloom Booster Flower Food

As we near the end of this list, here’s another product from Miracle-Gro that finds an honorable mention. Like a couple of our other recommendations, Bloom Booster Flower Food boasts of a quick-release formula that starts showing positive results from the get-go.

Miracle-Gro, 1-Pound 1360011 Water Soluble Bloom Booster...
  • For all blooming plants
  • Instantly feeds for beautiful results

Why Did We Like It?

First things first, the Miracle-Gro Bloom Booster Flower Food has a fertilizer blend of 10-52-10 that is ideal for all blooming flowers in general, especially for petunias. Its fast-feeding formula will appeal to users who are looking to initiate the plants’ blooming within a single growing season.

Unlike its predecessor, this fertilizer can be used for both indoor and outdoor plants. For the former, mix 1 tablespoon per gallon of water in a watering can (one refill pack should cover about 500 square feet). Similarly, use ½ tablespoon with each gallon when watering indoor plants. 

What appealed to us the most is the product’s double feeding action that helps the plant absorb nutrients through leaves as well as roots. Hence, you can also spray the solution all over without maintaining any restrictions.

Lastly, its special formulation is meant to be used once every 7 to 14 days before and during bud set and blooming stages.

What Could’ve Been Better?

We’d have liked this product better if the formula was a bit more gentle. As a result, you have to be extra cautious while following the measurements guide to avoid root burns. Other than that, we didn’t observe any significant advantage.


  • Suitable for containers, window boxes and annuals
  • Promotes bigger blooms
  • Dissolves quickly
  • Develops vibrant color


  • Can burn roots if not used as directed

NPK Ratio: 10-52-10 | Weight: 1 lb | Fertilizer Type: Granular | Application Method: Dissolve in water | Duration of Nutrient Release: Up to 7-14 days | Organic/Natural: No | Target Plants: Flowering plants

7. Southern Ag All Purpose Granular Fertilizer

The Southern Ag All Purpose Granular Fertilizer is made from a combination of balanced NPK ratio and other minor elements. Be it for flower beds, shrubs, trees, or vegetable gardens-this one can do it all.

No products found.

Why Did We Like It?

Frankly, the balanced NPK ratio is what made us want to try this product in the first place. This means that this fertilizer takes equal care of root development, flowering, and green leaf production. Hence, you don’t have to compulsorily switch over to or add any other feed/fertilizer during the growing season.

Not only that, but it also contains some other essential elements, which are required for the all-around proliferation of plants. Furthermore, the uniform homogeneous granular formulation ensures that each part of the soil receives an equal amount of nutrition. 

As far as its application is concerned, use 1 cup per 25 square feet every three months for petunia beds. In case you plan to use it for containers, decrease the amount while keeping the feeding cycle unchanged.

What Could’ve Been Better?

Firstly, the product comes in a bag of 5 pounds. Although it has a reasonable price tag, we wish there was a smaller package for trial purposes. Also, the instructions don’t specify the quantity to be used for container plants.


  • Highly effective NPK ratio
  • Can be used for various plant types
  • Ideal for all-round development
  • Reasonable price


  • Insufficient usage instructions

NPK Ratio: 10-10-10 | Weight: 5 lbs | Fertilizer Type: Granular | Application Method: Sprinkle around plants | Duration of Nutrient Release: Up to 6 months | Organic/Natural: No | Target Plants: All-purpose

8. Voluntary Purchasing Group Fertilome Plant Food Fertilizer

With a specialized formula for hanging and container plants, the Fertilome Plant Food Fertilizer. Its uniform NPK ratio makes it extremely effective for petunias and other flowering plants. What’s more, it’s designed to facilitate quick and optimum nutrient absorption.

Voluntary Purchasing Group 10728 Fertilome Geranium Hanging...
  • Highly Concentrated
  • For Hanging Baskets And Other Container Plants

Why Did We Like It?

The Fertilome Plant Food Fertilizer has a highly concentrated formula that promotes larger blooms and develops deep green foliage. Moreover, its balanced NPK ratio means that your plants get the right nutrients for complete development.

Similar to the Proven Winners Premium Fertilizer, its granular-like texture easily dissolves in water for convenient application. Use 2 tablespoons of the product per gallon and use it once every 10 to 14 days. Here, we should also mention that it’s meant exclusively for hanging baskets and container plants. 

Unlike the Aquatic Arts All-Purpose Indoor Plant Fertilizer, its affordable pricing doesn’t really bother users about its limited versatility. Besides, its zipper-lock packet is designed for secure storage. All in all, this fertilizer is one of the most affordable balanced feeds on the market.

What Could’ve Been Better?

We are pretty bummed out about its strong ‘stinky’ odor, which can be a nuisance for people who are sensitive to smell. On top of that, a fair bit of the product gets stuck in the crevices of the ziplock while pouring. We’d advise transferring it into an air-tight container before use.


  • Promotes healthy roots
  • Easily dissolves in water
  • Aids larger blooms
  • Comes with a measurement scoop


  • Smelly
  • Inconvenient packaging

NPK Ratio: 20-20-20 | Weight: 0.5 lb | Fertilizer Type: Granular | Application Method: Sprinkle around plants | Duration of Nutrient Release: N/A | Organic/Natural: No | Target Plants: All-purpose

Best Petunia Fertilizers Comparison Table

ProductNPK RatioWeightFertilizer TypeApplication MethodDuration of Nutrient ReleaseOrganic/NaturalTarget Plants
Miracle-Gro Shake ‘N Feed All-Purpose Plant Food12-4-85 lbsGranularShake and feedUp to 3 monthsNoAll-purpose
Osmocote 274850 Smart-Release Plant Food Plus15-9-128 lbsGranularIncorporation into soilUp to 6 monthsNoAll-purpose
Jobe’s Organics Container & Bedding Plant Fertilizer Spikes3-5-60.55 lbsSpikesSprinkle around plantsUp to 8 weeksYesContainer and bedding plants
J R Peters Inc 52624 Jacks Classic No.1.5 20-6-22 Petunia Feed20-6-221.5 lbsGranularDissolve in waterUp to 7-10 DaysNoPetunias
Proven Winners Premium Water Soluble Fertilizer24-12-172.5 lbsGranularDissolve in waterUp to 7 daysNoAll-purpose
Miracle-Gro 1-Pound 1360011 Bloom Booster Flower Food10-52-101 lbGranularDissolve in waterUp to 7-14 daysNoFlowering plants
Southern Ag All Purpose Granular Fertilizer10-10-105 lbsGranularSprinkle around plantsUp to 6 monthsNoAll-purpose
Voluntary Purchasing Group Fertilome Plant Food Fertilizer20-20-200.5 lbGranularSprinkle around plantsN/ANoAll-purpose

Buying Guide For The Best Petunia Fertilizer 

Now that you have the list of the best fertilizers for your petunias, the next step should ideally be to get one immediately. But allow us to make you take a small ‘detour’. Although all our recommendations stand the test of superior efficiency, your choice will yield satisfactory results only when it meets your requirements.

So, we’ve compiled this short buyers’ guide to help you identify the crucial factors that should drive your purchase decision.

  1. Type

By type, we mean the physical appearance of the fertilizer. If you’re a first-timer, we’d suggest going for a non-soluble formula to keep the application process simple. However, the soluble (both granules and liquid) products enhance absorption as they reach close to the roots as the water flows. Whatever be the type, its nutrient content should never be overlooked.

  1. Fertilizer Vs. Feeder

Fertilizers and feeders are made for the same purpose, i.e., enhancing nutrient intake. But there’s more to the story. While fertilizers are more dedicated to the cause of increasing the NPK content in the soil, plant foods contain a mix of a majority of the essential micronutrients.

As such, the decision to choose one depends on your needs. If you plan on providing all-around development, then feeders may have a slight edge over fertilizers as they may lack some vital elements.

In the case of fertilizers, we’d recommend going for a balanced NPK ratio for the best results. As an alternative, you can also opt for one that doesn’t lack or contain too much of a particular element.

  1. Feed Cycle

Simply put, the feed cycle is the time after which you’ll need to reapply the product. So that you’re saved from the hassle of frequent fertilizer, you may select a product that has a feed cycle of a couple of months. In the case of soluble fertilizers, the feed time shouldn't be much of a bother as you can use it simultaneously while watering the plants.

  1. Purpose

Some fertilizers are meant for all-purpose use or can be used only for a certain setting. But if you want to serve a dedicated purpose, we’d recommend investing in one that has a defined purpose or setting for use.

Petunia Fertilizers FAQ's

  • When should I fertilize my Petunias?

    For optimal results, it is recommended to start fertilizing petunias when they are actively growing. Generally, this is done after the plants have established a good root system, usually around 2-4 weeks after planting. During the growing season, you can continue fertilizing every 2-3 weeks to ensure a continuous supply of nutrients for healthy growth and blooming.

  • How often should I fertilize my Petunias?

    The frequency of fertilization depends on the type of fertilizer used and the specific needs of your petunias. In general, a regular feeding schedule of every 2-3 weeks during the growing season is recommended. However, it is important to read the instructions on the fertilizer package and adjust the frequency accordingly.

  • What is the best fertilizer ratio for Petunias?

    Petunias generally benefit from a balanced fertilizer ratio, such as 10-10-10 or 14-14-14, which indicates the percentages of nitrogen (N), phosphorus (P), and potassium (K) respectively. This balanced ratio provides a well-rounded nutrient profile that supports overall plant health, root development, and flower production.

  • Can I use a general-purpose fertilizer for Petunias?

    Yes, you can use a general-purpose fertilizer for petunias. However, it is important to ensure that the fertilizer contains the necessary nutrients and micronutrients required by petunias. Always check the label to confirm that the fertilizer is suitable for flowering plants and contains a balanced nutrient ratio.

  • Are organic fertilizers better for Petunias?

    Organic fertilizers can be a good choice for petunias as they provide nutrients in a slow-release form and improve the soil structure over time. They are typically derived from natural sources such as compost, manure, or plant-based materials. However, it is important to select organic fertilizers that are specifically formulated for flowering plants and provide a balanced nutrient profile.

  • Can over-fertilizing harm my Petunias?

    Yes, over-fertilizing can harm petunias and other plants. Excessive amounts of fertilizer can lead to nutrient burn, where the plant’s roots and foliage are damaged due to an imbalance or concentration of nutrients. It is crucial to follow the recommended dosage instructions on the fertilizer package and avoid applying more than necessary.

  • Should I water my Petunias after fertilizing?

    Yes, it is advisable to water your petunias after fertilizing. Watering helps to distribute the nutrients evenly in the soil and prevents the roots from getting burned. Additionally, watering also helps in flushing out any excess fertilizer that may be present, reducing the risk of nutrient buildup.

  • Can I use slow-release fertilizers for Petunias?

    Yes, slow-release fertilizers can be used for petunias. These fertilizers release nutrients gradually over an extended period, providing a steady supply of nutrition to the plants. Slow-release fertilizers are particularly beneficial for busy gardeners or those who prefer a set-it-and-forget-it approach to fertilizing.

  • blooming white Petunia in a hanging retro planters on the street


    Shortlisting the top names from near-similar ingredient lists and visibly enticing results took some effort, but it was all for a good cause!

    And we are pretty sure that by now, you have picked a couple of your favorites from our list. But if there's still some lingering confusion, our top three names will help you eliminate it.

    While the Miracle-Gro Shake ‘N Feed All Purpose Plant Food is one of the best products on the market, the Osmocote 274850 Smart-Release Plant Food uses a special process to ensure optimum nutrient intake. On the other hand, the J R Peters Jacks Classic Petunia Feed is soluble and easy to use.

    With this, it’s time for us to wrap up today’s guide. I hope we have brought you one step closer to a product that suits your needs, and of course, your budget. We’d love to hear your thoughts in the comments section below.

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