The Best Fertilizer for Potatoes of 2021

Increase your potato crop’s yield by feeding your plants with the best fertilizer.

By Savannah Sher | Published Nov 23, 2021 11:02 AM

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The Best Fertilizer for Potatoes Options

Photo: amazon.com

Growing potatoes is typically reserved for experienced gardeners because this tuber crop tends to be a bit finicky in terms of care requirements. Potatoes thrive in temperatures between 50 and 70 degrees Fahrenheit, require full sun, and need a loose, well-draining soil. Fertilizing is particularly important for potato crops, since they have somewhat high-maintenance nutrient needs. They need to be fertilized four to five times throughout their life cycle, and many farmers and gardeners use a different fertilizer blend each time.

With so many fertilizers available, it can be difficult for shoppers to narrow down their options. These recommendations for the best fertilizer for potatoes were selected for their quality, versatility, value, and ease of use. Keep reading to learn about the key features to consider when shopping, and then explore our picks for the best potato fertilizers on today’s market.

  1. BEST OVERALL: Southern Ag All Purpose Granular Fertilizer
  2. BEST BANG FOR THE BUCK: Miracle-Gro Water Soluble Plant Food
  3. BEST ORGANIC: Dr. Earth Organic Tomato, Vegetable & Herb Fertilizer
  4. BEST LIQUID: Fox Farm 6-4-4 Grow Big Liquid Concentrate Fertilizer
  5. BEST FOR RAISED BEDS: Nature’s Care Organic & Natural Raised Bed Plant Food
  6. BEST ALL-PURPOSE: Miracle-Gro Performance Organics Plant Nutrition
  7. BEST LARGE QUANTITY: Jobe’s Organics All-Purpose Granular Fertilizer
  8. ALSO CONSIDER: Winchester Gardens Select Organics Potato Fertilizer
The Best Fertilizer for Potatoes Options

Photo: amazon.com

What to Consider When Choosing Fertilizer for Potatoes

While it’s easy to assume that all vegetable fertilizers offer similar performance, a number of factors affect their functionality. Just ahead are several of the most important features to consider when choosing the best potato fertilizer for your yard or farm.

Types

When it comes to choosing a fertilizer, gardeners have two primary types to choose from: liquid and granular.

  • Granular fertilizers come in pellets or coarse powders and release nutrients over time, which is ideal for ensuring a proper balance of nutrition over a plant’s life cycle.
  • Liquid fertilizers act quickly and are immediately absorbed by the plants in your garden.

Gardeners also have to decide whether they want to use organic and inorganic fertilizers—or a combination of the two. Organic fertilizers contain no chemicals and are made from completely natural ingredients. One of the biggest perks of organic fertilizers is that they continue to condition the soil over time. Most products on the market, however, are inorganic, and utilize powerful chemicals that are expertly formulated to make soil ideal for growing vegetables. It’s important to avoid fertilizers that include a weed killer, since this may also kill your growing potato plants.

Nutrients

Before choosing a potato fertilizer, it’s prudent to test your land’s soil to see which nutrients it’s lacking. The following nutrients are generally beneficial to potatoes when balanced in the appropriate ratios:

  • Nitrogen stimulates stem and leaf development in plants, though an excess of nitrogen can negatively impact tuber growth.
  • Phosphorus results in higher tuber yields.
  • Potassium impacts plant output and reduces black spots.
  • Magnesium improves the growing conditions of sandy, low-pH soils.
  • Manganese helps to add acidity to high-pH soils.
  • Boron helps potato plants absorb calcium from the soil and improves potato skin texture.

Season and NPK Ratio

Potato plants take between 3 and 4 months to develop, and throughout their growing process, their fertilization needs change. Consider the ideal NPK ratio, which is the percentage of nitrogen (N), phosphorus (P), and potassium (K)) for each stage of growth. When planting, an NPK ratio of 15-15-15 is ideal. A month or two after they’ve been planted, potatoes need lots of nitrogen, so a fertilizer with an NPK of 34-0-0 is the best choice. An NPK of 12-12-17 or 14-7-21 is best for the last couple of months before harvest when the plants require more potassium.

pH Level

The ideal soil pH level for growing potatoes is slightly acidic, between 4.8 and 6.5. It’s important to test the pH level of your soil before planting, to establish whether a fertilizer is needed to raise or lower pH levels. If the pH is too high, apply a horticultural sulfur to the planting area before planting in order to quickly lower it. Throughout the growing season, choose a fertilizer containing manganese, which will keep pH levels low.

Amount of Fertilizer

The amount of fertilizer gardeners should apply depends on the size of their garden and the quality of their soil. Generally speaking, a 1,000-square-foot potato garden requires approximately 25 pounds of fertilizer over the plants’ lifespan. Gardeners can use that figure to calculate how much fertilizer their specific plot of land requires.

Our Top Picks

Now that you’ve learned more about potato fertilizers, it’s time to start shopping. The following are the top picks for the best potato fertilizers for your garden.

Best Overall

The Best Fertilizer for Potatoes Option: Southern Ag All Purpose Granular Fertilizer
Photo: amazon.com

Southern Ag’s granular fertilizer comes in a 5-pound bag and releases nutrients slowly over time, allowing gardeners to fertilize less frequently. It features a 10-10-10 balance of nitrogen, phosphorus, and potassium, meaning this is an all-purpose blend that works for both edible and nonedible plants. This balanced formula makes the Southern Ag fertilizer ideal for the initial fertilization process when the potatoes are planted. To use, broadcast the granules over the garden plot and water them into the soil. The manufacturer recommends using 1 cup of fertilizer per 25 square feet of land.

Product Specs

  • Type: Granular
  • Size: 5 pounds
  • NPK: 10-10-10

Pros

  • Well-balanced trifecta fertilizer
  • Good for all-purpose use
  • Affordable price

Cons

  • Only one size available

Best Bang for the Buck

The Best Fertilizer for Potatoes Option: Miracle-Gro Water Soluble Plant Food
Photo: homedepot.com

This natural fertilizer from Miracle-Gro features a unique, water-soluble formula that makes for easy application and gives plants an instant nutrient boost. With an NPK ratio of 18-18-21, it’s perfect for applying at the beginning of the growing season or in the last couple of months of growth when the potato plants require more potassium. While it works well for potatoes, it’s also versatile enough to feed the other vegetables, fruit, and herbs in a garden. Miracle-Gro recommends applying this fertilizer every 1 to 2 weeks during the growing season. The 2-pound bag should feed 800 square feet.

Product Specs

  • Type: Water-soluble
  • Size: 2 pounds
  • NPK: 18-18-21

Pros

  • Well-balanced 18-18-21 formula
  • Good for all-purpose use
  • Affordable price

Cons

  • Only one size available

Best Organic

The Best Fertilizer for Potatoes Option: Dr. Earth Home Grown Organic Granules Veggie Maker
Photo: acehardware.com

Those looking for the best organic fertilizer option should consider this formula from Dr. Earth. It contains probiotics, seven strains of soil microbes, and ecto and endo mycorrhizae (beneficial funguses), all of which contribute to a richer, more nutrient-dense soil. This formula is certified by the OMRI (Organic Material Review Institute) as well as the CCOF (California Certified Organic Farmers) as being organic and non-GMO. Since it’s free of chemicals and synthetic ingredients, this product, which has an NPK ratio of 4-6-3, is safe to use around children and pets. In fact, it’s made from feed-grade ingredients, so it’s not a problem if your livestock gets into it.

Product Specs

  • Type: Granular
  • Size: 4 pounds
  • NPK: 4-6-3

Pros

  • Totally organic formula
  • Good for all-purpose use
  • Non-GMO or synthetic chemicals
  • Slow-release nutrients

Cons

  • Low NPK percentage

Best Liquid

The Best Fertilizer for Potatoes Option: Fox Farm 6-4-4, 1-Pint Grow Big Liquid Concentrate
Photo: amazon.com

Fox Farm’s liquid fertilizer is versatile, containing earthworm castings, Norwegian kelp, and essential micronutrients with an NPK ratio of 6-4-4. This formula is best for the middle of a potato plant’s growth cycle because of its high proportion of nitrogen. For the best results, the manufacturer recommends adding 2 teaspoons of liquid fertilizer to every gallon of water and applying the mixture every other time you water the garden. The fertilizer should only be applied once the new plantings have had a few days to settle in.

Product Specs

  • Type: Liquid
  • Size: 1 pint
  • NPK: 6-4-4

Pros

  • Can be used on both vegetables and flowers
  • Concentrated formula
  • Features high-quality ingredients

Cons

  • Small size

Best for Raised Beds

The Best Fertilizer for Potatoes Option: Nature's Care Organic & Natural Raised Bed Plant Food
Photo: amazon.com

Vegetables grown directly in native soil have a nutritional advantage, whereas those grown in containers or raised beds need an extra boost of nutrients in order to thrive. This formula from Nature’s Care has an NPK ratio of 10-2-8, making it ideal for the first couple of months of potato plant growth.

To use, sprinkle half a cup of the granules into each square foot of raised bed and work them into the top 6 inches of soil before watering thoroughly. At each subsequent feeding, use a quarter cup of fertilizer per square foot. The 3-pound bag should be sufficient to feed a 4-foot by 4-foot raised bed for approximately 2 months.

Product Specs

  • Type: Granular
  • Size: 3 pounds
  • NPK: 10-2-8

Pros

  • All-purpose formula
  • High nutrient percentage
  • Specially formulated for raised beds

Cons

  • Granules must be worked into the soil

Best All-Purpose

The Best Fertilizer for Potatoes Option: Miracle-Gro Performance Organics Plant Nutrition
Photo: amazon.com

Those with small gardens who are looking for a single fertilizer will be well served by this versatile option from Miracle-Gro, which caters to both flowers and edible plants. The built-in shaker applicator makes it easy to sprinkle the granules evenly throughout the garden. For in-ground gardening, simply scatter the granules and then work them into the top 3 inches of soil. For container gardens, mix 2 tablespoons of fertilizer into every gallon of soil at the time of planting. If plants are already established, follow the instructions for in-ground gardens. Reapply the fertilizer every 4 to 6 weeks for the best results.

Product Specs

  • Type: Granular
  • Size: 2.5 pounds
  • NPK: 9-2-7

Pros

  • Suitable for containers or native soil
  • Good for all-purpose use
  • Convenient built-in applicator

Cons

  • Only one size available

Best Large Quantity

The Best Fertilizer for Potatoes Option: Jobe’s Organics 09524 Purpose Granular Fertilizer
Photo: amazon.com

With its 16-pound quantity and NPK ratio of 4-4-4, this bag of all-purpose fertilizer by Jobe’s Organics is an excellent all-around pick for most gardeners, whether they’re growing flowers, fruits, or vegetables. It’s completely organic, being certified by the OMRI, with a fast-acting granular formula. Due to its all-natural makeup, it’s safe to use around young children and pets.

The formula is designed to improve nutrient absorption; help plants resist pests; promote root growth; and create a healthy, diverse ecosystem in the garden. The bag is resealable, keeping the fertilizer fresh for longer.

Product Specs

  • Type: Granular
  • Size: 16 pounds
  • NPK: 4-4-4

Pros

  • Well-balanced 4-4-4 formula
  • Good for all-purpose use
  • Affordable price
  • Smaller sizes available

Cons

  • Low nutrient density

Also Consider

The Best Fertilizer for Potatoes Option: Winchester Gardens NPK 6-3-9 Select Organics Granular
Photo: amazon.com

The vast majority of fertilizers on the market are geared toward general vegetable gardening, but this one from Winchester Gardens, with its NPK ratio of 6-3-9, is specially formulated for potatoes. Since potatoes require a different mix of nutrients than other vegetables, a dedicated formula is a great choice for gardeners looking to achieve the best results. It’s designed to promote all-around growth in sweet potatoes, bakers, boilers, and reds. Each bag comes with a spoon, making it easy to scoop out and apply to your garden’s soil.

Product Specs

  • Type: Granular
  • Size: 3 pounds
  • NPK: 6-3-9

Pros

  • Specially formulated for potatoes
  • Includes spoon for easy application
  • All-natural ingredients

Cons

  • Only one size available

Our Verdict

After reviewing our guide, you’ll now know more about shopping for fertilizer for your potatoes. We recommend the Southern Ag All Purpose Granular Fertilizer for its balanced NPK ratio and excellent value. Those on a budget will appreciate the Miracle-Gro Water Soluble Plant Food, which offers top-notch quality at an affordable price.

How We Chose the Best Fertilizer for Potatoes

Years of experience covering home and garden products as well as extensive product research went into creating this guide. We explored more than 40 fertilizer options and weighed a number of practical considerations before making our recommendations.

  • Nutrient mix: We aimed to include fertilizers with a high number of nutrients and made sure to feature options with a variety of NPK blends for different times in the growing cycle.
  • Reviews: We took customer reviews into consideration when making our recommendations, ensuring users had a positive experience with the fertilizer in terms of performance, ease of use, and ultimate yield.
  • Value: Growing your own vegetables should save money for your household, so we aimed to include fertilizers that offered excellent value based on their quality and quantity.

FAQs

While you now know more about choosing the best potato fertilizer, you might still be looking for more information about how to use it. Here are answers to some of the most frequently asked questions about fertilizing potatoes.

Q. When should I start fertilizing my potatoes?

Fertilize the soil before planting, if needed. Alternatively, fertilize simultaneously while planting.

Q. How much fertilizer should I use on potatoes?

A 1,000-square-foot plot requires approximately 25 pounds of fertilizer throughout the season.

Q. How do I apply fertilizer to potatoes?

The application depends on the type of fertilizer being used. Liquid fertilizers are meant to be mixed with water and applied while watering. Granular fertilizers are sprinkled on top of the soil or mixed into the soil before planting.

Q. How do you increase the yield of a potato crop?

Increase your potato crop’s yield by initially cutting your seed potatoes into small pieces, about the size of a standard ice cube, and starting them in a warm area. Throughout the growing season, ensure the soil is well fertilized and isn’t allowed to dry out.

Q. Is Epsom salt good for potatoes?

Yes, Epsom salt contains magnesium, which is beneficial for potatoes and improves growing conditions.

Q. Do potatoes like coffee grounds?

Adding coffee grounds to your compost blend is a great way to increase growth.