6 Best Fertilizer for Potatoes That We Recommend

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There’s probably nothing tastier than French fries.

But even tastier it’s when the potatoes come from your own garden.

Growing potatoes at home is not easy, though. That’s why you should have as many aids as possible for the job to go well.

This includes the best fertilizer for potatoes. Nothing will help you grow those potatoes real big and tasty like a quality bag of fertilizer.

Down To Earth Langbeinite Sulfur Potassium & Magnesium Fertilizer

Down To Earth Langbeinite Sulfur Potassium & Magnesium Fertilizer

Our Top Recommendation for Fertilizer for Potatoes!

The Down To Earth Langbeinite Sulfur Potassium and Magnesium Fertilizer, 50 lb, is made of the highest quality ingredients that offer a friendly approach to plant care, fertilization, and soil maintenance. The combo of potassium, magnesium, and sulfur makes this fertilizer an ideal component required for plant growth.

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If you don’t know what fertilizer to go for, we have precisely the guide for you.

Check below for a complete explanation of all the fertilizers we recommend – plus a heads-up on how to pick the right one!

Fertilizer for Potatoes Reviews 2021

Down To Earth Langbeinite Sulfur Potassium & Magnesium Fertilizer• A unique 3-in-1 combination of Potassium
• Crop fertilization and soil management
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Greenway Biotech Sul-Po-Mag 0-0-21.5 Potash• Potassium Magnesium Sulfate is derived from Sulfate of Potash-Magnesia
• 50 Pounds Potassium Magnesium Sulfate fertilizer contains 22% Soluble Potash, 10.5% Magnesium, and 21% Sulfur
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Winchester Gardens Select Organics 6-3-9 Granular Potato Fertilizer • 3 Lbs. package
• Encourages all-around growth
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Garden Naturals Natural Potash 0-0-60 Fertilizer• Natural Potash by Garden Naturals 25 Lbs
• Great Source of Potassium
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AeroGarden 4-3-6 Liquid Nutrients• Works in all Miracle-Gro AeroGarden models
• Patented, pH buffering system great for all hydroponic applications
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Miracle-Gro Performance Organics Edibles 7-6-9 Plant Nutrition Granules• Covers up to 220 sq. ft.
• Use Miracle-Gro Performance Organics Edibles Plant Nutrition Granules to feed tomatoes, vegetables, herbs, and fruits
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Make no mistake, growing potatoes without fertilizer can be a HUGE disadvantage.

Not only will it promote less growth, but it will also prevent the potatoes from getting strong enough to avoid diseases and pests.

If you want to avoid a weak potato plant, look no further than the fertilizers below.

We’ve assembled this list focusing on a set of features, going from their quality of composition (excellent NPK ratio) as well as their effectiveness.

#1. Down To Earth Langbeinite Sulfur Potassium & Magnesium Fertilizer

Down To Earth Langbeinite Sulfur Potassium & Magnesium Fertilizer
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This naturally mined crystalline mineral provides the water-soluble sulfate form of three essential plant nutrients – magnesium, sulfurs, and potassium. It contains 22% K2O, 22% S, and 11% Mg. The Down To Earth’s Langbeinite 0-0-22 is known to have less than 3.0% of chlorine. Now, this reduces the chances of fertilizer ‘burn.’ Moreover, its neutral pH doesn’t change the soil activity.

Down To Earth Langbeinite Sulfur Potassium & Magnesium Fertilizer Review

Potassium regulates the internal process, thereby increasing overall plant health. Potassium is found throughout plant tissue as it makes up part of the plant fluid. So plants require a good source of potassium while they grow. On the other hand, magnesium is essential for the synthesis of chlorophyll and sulfur for the activation of the enzyme. 

Unboxing of Down To Earth Langbeinite Sulfur Potassium & Magnesium Fertilizer

DTE Langbeinite 0-0-22 is made of perfectly blended organic nutrients in ideal proportions with no synthetics, low-quality fillers, or growth stimulants. Overall, it is an excellent source of readily available potassium, magnesium, and sulfur.

Down To Earth Langbeinite Sulfur Potassium & Magnesium Fertilizer Mixing in the Water


  • Ideal for organic gardening
  • Clean, organic, and easy to use
  • A unique 3-in-1 combination of potassium, Sulfur & Magnesium
  • Tons of potassium for better root size


  • The bag doesn’t come properly sealed.
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#2. Greenway Biotech Sul-Po-Mag 0-0-21.5 Potash

Greenway Biotech Sul-Po-Mag 0-0-21.5 Potash
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A BIG BAG OF FLAVOR-GIVING POTASH! That’s what the Sul-Po-Mag from Greenway offers.

Boasting 50 pounds with 21.5% of pure potassium plus 10.8% of magnesium and up to 22% of sulfur, this fertilizer is nearly perfect for any potato plant.

The advantage comes from the potash ability to dissolve over several weeks in the soil. This results in a super-rich composition that the root (the potato itself) absorbs for maximum growth.

Having a bit of magnesium and sulfur sets the potash on another level. They add an extra bit of flavor, so your potatoes will end up as delicious as you can imagine.

Greenway Biotech Sul-Po-Mag 0-0-21.5 Potash Review

The best of all? Such a big bag. At 50 pounds, you’ll have enough to fertilize entire rows of potatoes for a whole season.

If you have only a few plants, this will be enough for a YEAR or even more.

And if all that wasn’t enough, the potash contains little to no chloride. There’s no chance your potatoes will suffer from this fertilizer.


  • A gigantic bag will last you a while
  • Tons of potash for better root (potato) size
  • Tons of micronutrients for extra results
  • Adds up a bit of taste to the yields


  • The bag is way too big for regular home use
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#3. Winchester Gardens Select Organics 6-3-9 Granular Potato Fertilizer

Winchester Gardens Select Organics 6-3-9 Granular Potato Fertilizer
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A completely organic fertilizing mix, the Select Organics from Winchester is no joke.

At 6-3-9 of NPK ratio, it comes with sufficient potassium to get your potatoes on a whole new level.

Growing Plant Using Winchester Gardens Select Organics 6-3-9 Granular Potato Fertilizer

It lacks a bit of phosphate, which reduces the flavor boost. But it comes with more than enough nitrogen to add extra protection (more vigorous foliage).

Did we mention it’s completely organic? That’s probably the best about this fertilizer. No chemicals or inorganic ingredients to worry about.

Putting Growing Plant Using Winchester Gardens Select Organics 6-3-9 Granular Potato Fertilizer in potato plant

And for those who want the bag to last, they’ll be happy to know it is a 3-pound package that lasts an entire season.

PLUS: This bag comes with its own spoon, so you won’t have to pour the fertilizer by hand. Grab the spoon and pour with care as you need.


  • Nearly flawless NPK ratio for potatoes
  • Boasts a spoon for easy application
  • Totally natural ingredients for safety
  • Easy to open and close the zip-lock bag


  • Tends to run out quickly
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#4. Garden Naturals Natural Potash 0-0-60 Fertilizer

Garden Naturals Natural Potash 0-0-60 Fertilizer
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Yet another bag of potash, this time at only 25 pounds. BUT A QUALITY 25-POUND!

Boasting a 0-0-60 NPK ratio, it is almost pure potash. At 60% of potassium, this bag’s whole purpose is to promote vigorous growth of the root. When it’s time to get it out of the soil, you’ll see the biggest potatoes out there.

Garden Naturals Natural Potash 0-0-60 Fertilizer Review

It’s also essential to understand how helpful potassium is at preventing diseases. Your potatoes won’t only grow BIGGER but also HEALTHIER.

Last but not least, it is entirely organic. A 25-pound of pure potash to grow your potatoes with all the benefits potassium offers (and none of the chemical drawbacks). 


  • Decent size for most situations
  • Tons of potash for sustained growth
  • The practical zip-lock bag design
  • A thoroughly natural composition


  • Surprisingly affordable for the size
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#5. AeroGarden 4-3-6 Liquid Nutrients

AeroGarden 4-3-6 Liquid Nutrients
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We couldn’t forget about liquid fertilizers.

And the AeroGarden Liquid Nutrients is the best you can get for your potatoes.

The reason? An almost perfect NPK ratio at 4-3-6. That means 4% of nitrogen for healthy foliage growth, 3% phosphorous for a bit of taste and color, and 6% of potassium for root-growth boost.

AeroGarden 4-3-6 Liquid Nutrients Review

What’s even better, AeroGarden adds a ton of other nutrients and micronutrients to the fertilizer. Your potatoes will enjoy immaculate nutrition.

But there’s something cool about this nutrient-rich mix: it also helps with germination. If you’re growing potatoes from seed, you’ll love how effective this fertilizer is at making them sprout.

Growing plant using AeroGarden 4-3-6 Liquid Nutrients

DON’T FORGET: It boasts a pH bufferingg so you can use it in clean environments (hydroponics). At 33 ounces of total fertilizer, it can last you 100 feedings or more.


  • It gets absorbed super-quickly
  • Doesn’t change soil’s pH
  • Helps with germination and root growth
  • Boasts tons of quality micronutrients


  • Runs out quickly

#6. Miracle-Gro Performance Organics Edibles 7-6-9 Plant Nutrition Granules

Miracle-Gro Performance Organics Edibles 7-6-9 Plant Nutrition Granules
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The most popular brand on the whole list, Miracle-Gro delivers one of the most complete fertilizers for potatoes.

At 7-6-9 of NPK ratio, the Performance Organics Edibles fertilizer offers highly nutritious granules that will make even the unhealthiest soils a lot more livable for potatoes.

Miracle-Gro Performance Organics Edibles 7-6-9 Plant Nutrition Granules Review

But it still contains 9% of potassium against 7% and 6% of nitrogen and phosphorous. That’s an excellent mix for potatoes, giving it’ll boost root growth over anything else.

Despite coming in a bottle, these granules are dissolvable. Meaning, you need to pour them over the soil and water them down to be absorbed.  Surprisingly, Miracle-Gro claims it starts working in as little as 7 days.

Inside a Miracle-Gro Performance Organics Edibles 7-6-9 Plant Nutrition Granules

And lastly, this is a 2.5-pound bottle of granules. But it can last an entire season, covering over 220 square feet. You get more than enough for almost any use case.


  • Dissolves on soil for quick absorption
  • A decently large bottle that lasts long
  • Excellent NPK ratio for sustained growth
  • Covers a lot of ground


  • Dogs and cats will eat it if not dissolved right away
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How to Choose the Right Fertilizer for Potatoes

So you’ve decided to get one of these fertilizers… but you aren’t sure yet.

We know how hard it is to pick one when you probably have not much idea of what works.

Don’t worry – let us explain what you should consider and what you should avoid then. Check our guide below:

NPK Ratio (Nitrogen, Phosphorus, Potassium)

The first and probably the most question to ask yourself is: how many of the RIGHT nutrients the fertilizer has?

To answer that question, you’ll have to look at the NPK ratio.

You see those numbers separated by dashes in the name, package, or bottle of the fertilizer? That’s the ratio we’re talking about.

The N-P-K refers to Nitrogen, Phosphorous, and Potassium by their chemical symbols. Those are the nutrients that every fertilizer should count.

These numbers refer to the percentage of these nutrients. For example, a 6-6-6 NPK ratio means 6% nitrogen, 6% phosphorous, and 6% potassium.

NOW, what ratio is the best for growing potatoes?

Well, the best fertilizer for a potato plant would be anything with high potassium, a decent amount of nitrogen, and a bit less phosphorous.

For example, a fertilizer with 4-2-8 NPK would be perfect. If it has the same amount of nitrogen and potassium, that would also work.

Having said that, nitrogen is not always needed. If you have nutritious soil already, you can skip it. 

That’s why you can pick Potash instead. This is the name for a fertilizer that contains only potassium. And A LOT of potassium most of the time, typically over 30% of total content.

So, if you’re going for a quality fertilizer for potatoes, make sure it has more potassium than anything else.

Extra Nutrients

The NPK nutrients aren’t the only ones you can get from fertilizers. Some mixes sometimes offer TONS of other nutrients and micronutrients that help in growth and vegetable production.

These include sulfur and calcium, magnesium, and many others. These are rich mixes that you shouldn’t dismiss.

Some micronutrients even help with sprouting and flavor. That’s why getting fertilizers with many other nutrients also helps a lot.

Type of Fertilizer

Once you’re done deciding how many nutrients your plants need, check whether you want granules or liquid fertilizer. We explain a little bit of both below:


Not as broken down as powder, granules are pellet-like that you pour over the soil. They need some mixing with the soil so they break down more quickly and get absorbed. These are excellent for slow-release results, as the granules often take several weeks to break down completely.


In case you don’t want to wait weeks for the fertilizer to break down, choose a liquid version. You also need to pour over the soil, but like you would use any liquid. Obviously, it breaks down quickly and requires more consistent applications. Yet, it tends to help a lot in the early growing stages.

Amount and Durability

Lastly, you should always consider how much fertilizer you’re getting per bag or bottle.

You don’t want a small bag of fertilizer for an entire farm row of potatoes. Similarly, you don’t want a gigantic bag of granules for only two or three plants.

It’s vital to measure well enough before picking. Generally, 1 pound of granules tends to last about a month or two for one or two potato plants.

As for liquid fertilizer, you’ll need about 30 ounces per plant per season.

It depends a lot on whether you’re applying on garden soil, in pots, garden beds, and whatnot. Meaning, the size of the place and the number of potatoes will tell you how much fertilizer you’ll need. Pick accordingly.

Organic vs. Synthetic Fertilizer for Potatoes

You may have noticed how some fertilizers claim to be utterly organic while others contain some synthetics.

Potato plants don’t care about this. But if you are picky and want to avoid chemicals in your potatoes, check what we have to say:

Synthetic Potato Fertilizers

Suffice to say, these use chemical sources instead of natural ones. The results? A LOT QUICKER ABSORPTION.

Why in caps, you’d ask… Well, it’s because it’s really a lot faster.

The way chemical fertilizers are absorbed is swift, especially in liquid form. They can reach the roots of the plant within a day or two of being applied.

Some slow-release synthetic fertilizers take a few months to be completely absorbed. But these are rare.

Sadly, most of these fertilizers are macronutrient rich but don’t often have micronutrients. Meaning, you may miss the advantages of calcium and magnesium for the potatoes.

As a last disadvantage, these may often contain chlorine and other not-so-good chemicals you may not like in your potatoes. If that’s something you care about, then go for organic fertilizers instead.

Organic Potato Fertilizers

In contrast with synthetic alternatives, organic ones come from natural sources.

This includes meals like blood, bone, cottonseed, fish, alfalfa, and feather meal. Some may also come from corals and even rock formations, as they tend to contain a lot of macronutrients, typically potassium.

The contrast with synthetic ones is their releasing speed. These are A LOT slower. Natural liquid fertilizers are a bit faster but don’t match inorganic ones.

One huge advantage is that organic fertilizers have no drawbacks. If you apply too much, there’s little to no damage to the plant, as they release reasonably slowly.

And what’s even better, these usually contain TONS of other micronutrients like magnesium, calcium, sulfate, and more. The result? Quicker growth and bigger, healthier potato plants.

Frequently Asked Questions (FAQs)

We know how confusing all this information can be. Plus, you probably have tons of doubts and questions that need answers. Here’s are a few common questions with their respective answers:

Q1. How much fertilizer per acre for potatoes?

Ans: It depends on what type of fertilizer you’re using. Generally, you need up to 100 pounds in some cases or as little as 25 pounds. In that case, you will need to buy either a large bag of fertilizer or several small ones.

Q2. What fertilizer to use for potatoes in containers?

Ans: To know this, you will have to test the soil first, as it’s almost impossible to give a fair assessment without that. However, potatoes in containers often use potting soil, which is already rich. In that case, a potash fertilizer would be a great choice. If the soil is of low quality, pick a fertilizer with a balanced ratio.
Either way, it’s always worth adding manure or compost to the soil in containers. This can be even more helpful than using fertilizer.

Q3. Should you use the same fertilizer for sweet potatoes?

Ans: Yes. Potatoes and sweet potatoes grow the same way and require the same nutrients. There’s no difference.

Q4. How to make a homemade fertilizer for potatoes?

Ans: The best type of fertilizer you can make at home is compost. While it is referred to as compost, it’s probably the best fertilizer you can use. For potatoes, banana peels, wood ashes, and coffee grounds work perfectly.


There’s no point in letting your potatoes grow small and unhealthy when you can use the best fertilizer for potatoes and help them THRIVE!

Fertilizer is not a magical product that will prevent all the issues your plants may experience. But it will HELP your plant grow healthier, bigger, and more beautiful (HAVE WE MENTIONED TASTIER?)

Anyway, this guide on picking a suitable fertilizer should help you get the right one for your potatoes. Follow our advice and recommendations to get precisely what you need.

You won’t regret it!

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