8 Best Fertilizer for Potatoes for Bigger & Better Harvests

Use the best potato fertilizer to increase your yield and have the healthiest potato plants!

Potatoes are one of the most important root vegetables we grow on our homestead. We want a large harvest, which means using the right fertilizer for potatoes to boost our production.

Truth be told, for years, I failed to use fertilizers. I thought well-rotted manure or compost was good enough, and sometimes, that is true. Other times, your plants need more help to reach their optimal growth.

I used potato fertilizers this year, and the results spoke for themselves. I harvested well over 100 pounds of spuds!

We started by adding compost to our garden beds before planting our seed potatoes and using a slow-release, balanced fertilizer. Be sure to check the pH of your soil; you don’t want soil that is too acidic or alkaline. The ideal range is between 6.0 to 6.5.

Then, side-dress the top of the soil around your plants throughout the growing season. Consider using phosphorus and potassium-rich fertilizer as well; liquid fertilizers work well for this. Be sure to stop fertilizing a month before harvesting to give the plants time to slow down their growth and production.

It all starts with picking the best potato fertilizers, so let’s look at some of my top picks.

Related: Answering: How Long Do Potatoes Take to Grow?

8 Best Fertilizer for Potatoes

These are some of the best potato fertilizers for home gardeners. These may not be ideal for your production if you are a farmer.

Related: 10 Best Fertilizer for Cucumbers for Bigger Yields & Better Growth

1. Dr. Earth Organic 5 Tomato, Vegetable & Herb Fertilizer

At the top of my list is Dr. Earth Organic 5 Fertilizer. Take a look at the tens of thousands of positive ratings, and you’ll understand why I put this at the top of the list.

Dr. Earth Organic is proven to be effective in vegetable gardens. It works well as a top dressing, side dressing, or water-soluble tea fertilizer. The mixture contains probiotics and seven types of beneficial macrobiotics.

Earth Organic Fertilizer enriched this with humic acid, fishbone meal, fish meal, and alfalfa meal. All of these contribute to healthy potato growth.

All of these work together to produce a better potato harvest. Reviews say plants often double in overall size when using this fertilizer for potatoes. This is a 4-6-3 NPK ratio, which means it slightly has more phosphorus than nitrogen and potassium. Phosphorous contributes to strong root development.

For best results, plan to reapply every two months.

PROS

• Great Value for Your Money
• Organic
• Hand-Crafted Blend
• Slow-Release Fertilizer
• It Contains Probiotics and Beneficial Microbes

CONS

• Bad Odor That May Attract Wildlife

2. Miracle-Gro Performance Plant Nutrition Granules

Most gardeners recognize the name Miracle-Gro, and their Performance Plant Granules are a slow-release option you will love. Their organic formula is dependable and will provide you with the bumper crop you hoped to have.

The NPK ratio is 7-6-9, so it has a bit more potassium than other options. More potassium ensures the best yield while providing more resistance against diseases. Plus, it means your harvest will store longer, and the potatoes will have a rich flavor.

It’s hard not to love that!

Miracle-Gro designed this fertilizer to have a flip lid dispenser, so it’s easy to shake and pour the granules around the base of your plants. Repeat applications every four to six weeks to see the best results.

PROS

• Increases The Yield of Your Plants
• 7-6-9 NPK
• Extra Potassium
• Easy to Apply to Garden

CONS

• Not a Water Soluble Fertilizer

3. Jobe’s Organics Vegetable & Tomato Plant Food

I regularly use Jobe’s Organic Plant Food; it’s readily available at my local Rural King. Over the years, I have had great success with their products, and I suspect you will also. I always recommend their products!

Jobe’s Vegetable & Tomato Plant Food is a granular, slow-release product that uses microorganisms to break down the granules in the soil. The NPK ratio is 2-5-3, perfect for most vegetable plants.

So, when compared to other fertilizers for potatoes, the roots will receive nutrients faster. You also benefit from improved soil quality and increased defenses against potato plant diseases.

Using Jobe’s Organics is easy. Apply some around your potato plants early; mix it into your compost when planting. Then, apply every six to eight weeks for a continuous supply of nutrients to your plants.

It’s important to note that Jobe’s received the OMRI seal of approval, which means this is a certified organic product for gardening. It won’t contain any synthetic chemicals.

PROS

• Lasts Up to 6 Weeks
• Uses a Proprietary Blend of Microbes

CONS

• A Slightly Strange Odor

4. Epsoma Organic Garden-Tone Fertilizer

Epsoma is a popular fertilizer for potatoes and vegetable gardens in general. It’s regularly sold at stores like Wal-Mart or other garden stores.

Garden-Tone is an organic, granular formula that is great if you already have nitrogen-rich soil. The NPK ratio is 3-4-4, including bio-tone microbes that provide a steady distribution of nutrients throughout the soil.

Garden-Tone is easy to work with; the granular formula mixes well into the soil or compost. This is a slow-release formula, so apply the first application when you plant your potatoes. Then, apply every month afterward to give your plants a continuous source of nutrients for optimal growth.

PROS

• Quick Results
• 3-4-4 NPK
• Includes Microbes

CONS

• Strange Odor That May Attract Pests

5. Epsoma Organic Bone Meal Fertilizer

If you look in my garden shed, I always have a bag or two of bone meal fertilizer. Epsoma Bone Fertilizer is an excellent option for adding phosphorus and calcium to your soil based on early soil testing. Adding this fertilizer helps create acidic soil.

The best time to use a bone meal fertilizer for potatoes is in the fall before planting in the spring. This gives the slow-release fertilizer time to break down and work properly. However, it’s possible to fertilize a new crop with it, so long as you only apply once – before or right during planting.

Remember, this is a slow-release fertilizer, so it takes time to see the results.

PROS

• 100% Organic with No Fillers or Additives
• High Phosphorus Content
• Only Need One Application

CONS

• Smelly!
• Contains No Potassium

6. The Old Farmer’s Almanac Organic Tomato & Vegetable Food

Everyone recognizes Farmer’s Almanac, and their organic fertilizer is an OMRI-listed choice. It offers a slow-release fertilizer for potatoes in all stages of growth. Mix the granules with your compost or soil, and you’ll see results faster than you expect.

Reviews remark that this potato fertilizer has no nasty odor. Many fertilizers have bad odors, which increases the risk of animals finding your garden. You don’t have to worry about that with Farmer’s Almanac.

This granular fertilizer has an NPK ratio of 8-4-8, which means it has less phosphorus. It comes from a mixture of bone meal, blood meal, feather meal, soybean meal, and more. That means it’s safe to use on most plants.

It’s best to reapply this fertilizer every six to eight weeks for optional results.

PROS

• No Harsh Smells
• Works Quickly

CONS

• Too Much Watering Leads to Fungal Growth

7. Down to Earth Organic Vegetable Garden Fertilizer

I’m a fan of Down to Earth and its various fertilizers. I tried several varieties, and all of them worked wonderfully.

Their Organic Vegetable Garden Fertilizer offers an equal, 4-4-4, NPK ratio that feeds your plants and complements your compost. Since it is an equal NPK, you never have to worry that it will burn or damage your plants. This fertilizer is safe, and the nitrogen portion is water-soluble.

The only downside, I feel, is that Down to Earth recommends applying twice per month. That means you may need to buy more than one fertilizer container for your gardening season.

PROS

• Equal NPK Ratio
• Gentle for Heavily Amended Soil
• No Harsh Odor

CONS

• Higher Price than Others
• Must Use Regularly

8. Fox Farm Grow Big Liquid Concentrate Fertilizer

If you prefer a liquid fertilizer, Fox Farm is an excellent and trustworthy brand to consider. This concentrate is a versatile option that contains earthworm castings, Norwegian kelp, and plenty of micronutrients. It has an NPK ratio of 6-4-4, an excellent ratio for the early and middle portion of a potato plant’s growth cycle.

Fox Farm makes it easy to use their concentrate.

All you have to do is add two teaspoons of concentrate for every gallon of water. I often mix this in a five-gallon bucket, so I only need ten teaspoons. A bottle lasts quite a while when this is used and mixed properly.

PROS

• Safe for All Vegetable Plants
• Concentrated
• 6-4-4 NPK Ratio
• Great Ingredients

CONS

• Small Bottle Size for the Price

How to Pick the Best Fertilizer for Potatoes

The Type of Fertilizers for Potatoes

Fertilizers come in various types, each with pros and cons to consider. So, let’s look at the type of fertilizer you may find in the garden store.

Slow-Release Fertilizer

Most granular fertilizers in the store are slow-release fertilizers that provide a steady stream of nutrients to the plants over an extended period. These fertilizers prevent your plants from receiving high doses of nutrients all at once, which is problematic.

One of my favorite ways to use a granular fertilizer is side-dressing. I sprinkle some fertilizer next to my plants regularly, knowing they will slowly break down and feed the plants.

Quick-Release Fertilizer

Typically, quick-release fertilizer comes in a water-soluble form that immediately provides nutrients to your plants. Quick-release is the best option for you if they need a fast boost or accelerated improvement, such as if you planted in poor soil.

You most often find this form as liquid fertilizers. Liquid fertilizers are easy to use; mix with water and use a watering can or your hose to spray the dirt around your plants.

Urea Fertilizer

Urea is a common source of nitrogen used for commercial fertilizers. Natural urea is a metabolic waste byproduct of animals, so it’s considered an organic fertilizer.

Many potato farmers use urea fertilizers because of their high nitrogen content, and it’s relatively affordable. Plus, if it rains too much, the fertilizer is still effective.

Nutrients in Potato Fertilizer

Make sure you consider the nutrients in the fertilizer and use soil analysis to determine which is best for your garden.

Look at the NPK ratio of each fertilizer. A balanced fertilizer with equal ratios of all three is a safe choice, but if you know you lack certain nutrients, look for a fertilizer higher in that nutrient.

Here are some nutrients you’ll find in potato fertilizers that help the growth of your plants.

• Nitrogen: Stimulates stem and leaf development in plants, but applying too much will negatively impact your plants.
• Phosphorus: Leads to higher tuber yields
• Potassium: Impacts plant output and reduces black spots (and other potato plant diseases)
• Magnesium: Helps with the growing condition in low pH, sandy soils
• Manganese: Adds acidity to high-pH soils
• Boron: Helps potato plants absorb calcium from the soil and improve potato texture.

Organic vs. Non-Organic Fertilizer

Next, you have to decide if you want organic fertilizers or non-organic fertilizers.

Organic fertilizers contain natural ingredients, such as seaweed, compost, and cow manure. Nutrients slowly seep into the soil, but it is effective and helps reduce nutrient leaching. A bonus of using organic fertilizers is that they tend to improve the overall soil structure and quality.

However, organic fertilizers often have a strange smell.

A non-organic, chemical fertilizer is synthetic and made from various chemicals. These fertilizers tend to release faster into the soil, but some slow-release options are available.

The problems with these fertilizers are that they contain chemicals – what is really in them – and over-fertilizing is harmful with these types of inorganic fertilizers.

Fertilizing Potato Plants Basics to Know

Like all plants, potato plants need a healthy environment to grow and nutrients throughout the growing season. That’s your best chance to have a bountiful harvest. Using fertilizers for potatoes provides the plants with the nourishment needed for optimal growth.

Let’s look at some basic information you need to know to fertilize potato plants successfully.

The Best NPK Ratio for Potato Fertilizers

Before buying fertilizer for potatoes, make sure you get one with an ideal NPK ratio. Potato plants grow well with a 2-2-3 fertilizer (2% nitrogen, 2% phosphorus, 3% potassium). You might not find this exact ratio, but try to find it as close as possible.

Aside from adding fertilizer, be sure to put compost into your garden beds. Compost provides your plants with additional nutrients throughout the growing season since it takes longer for organic matter to break down.

Here is the breakdown of the nutrients your potato plants need for optimal growth.

Nitrogen

All plants need nitrogen, and potato plants are no exception. Potatoes use nitrogen throughout the photosynthesis process, converting solar energy into carbohydrates.

These plants require decent nitrogen throughout the growing season because they continue to produce tubers. However, it’s best not to add too much nitrogen towards the end of the season because you want the plants to focus less on leafy growth and more on tuber development.

Related: 11 Natural Nitrogen Sources All Gardeners Need to Know

Phosphorus

Another necessary nutrient for all plants is phosphorus. This nutrient encourages the healthy growth of tubers and more offshoots, which gives you a larger yield. Poor soil often lacks sufficient phosphorus; use a soil test to determine if you need to boost up the amounts before planting your potato seeds.

Potassium

All plants also need potassium; your potato yield will be sad without sufficient amounts. Potassium works with your plant to deliver all essential nutrients and carbohydrates throughout the entire plant.

It’s also said that potassium ensures the potatoes store well and gives them adequate flavor when cooked. So, don’t forget to add it throughout the growing season!

What is the Ideal Soil pH for Potato Plants?

Potato tubers grow best in acid, loose soil; this leads to the best yields. Use pH strips for your garden to ensure your soil is at the proper levels, between 4.8 and 6.5. This level is considered slightly acidic.

If your pH is too high, using sulfur helps to add acid before planting.

When Should You Fertilize Potato Plants?

Timing is everything when it comes to fertilizing potato plants. It’s best to start early.

Apply compost and fertilizer one to two weeks before planting potato tubers. This gives the fertilizer time to absorb into the soil. In general, it’s wise to apply fertilizer before planting to encourage growth.

How Often Should You Fertilize Potato Plants?

How often you fertilize your potato plants depends on the type of fertilizer you use. If you use a slow-release, granular fertilizer on your garden beds before planting, then you may not need to fertilize for six to eight weeks after planting.

Ideally, you perform a soil test before planting and know if your soil is nutrient-deficient. If so, you may also want to apply a liquid fertilizer throughout the growing season. These are like little boosts of nutrients throughout the season.

Applying a calcium-rich fertilizer two to four weeks after planting is a good idea. Calcium is much-needed for plant cell development.

Can You Over-Fertilize Potato Plants?

Yes, it’s possible to over-fertilize vegetable plants, including potato plants. Doing so is harmful to your plants. Not only can adding too much fertilizer burn your plants, but it also leads to a reduced yield.

Despite our assumption that more is better when it comes to fertilizing potatoes, it’s always best to err on the side of caution. Use less, not more.

How to Fertilize Potato Plants

Learning how to fertilize potato plants is just as important as finding the fertilizer for potatoes. Fertilizing done improperly is just as bad – if not worse – than not using fertilizer at all.

The first step is to use a soil test. At-home tests are fast but aren’t as accurate as laboratory-tested soil tests. Your local extension office should offer soil testing for a small fee.

Once you know the nutrients your soil lacks, it’s time to add nutrients. I always add compost or well-rotted manure; it’s one of the best ways to amend your soil. Then, considering any nutritional deficiencies, add a granular fertilizer to the soil before planting.

Plant your seed potatoes one to two weeks after amending the soil. Then, based on the fertilizer’s recommendations, plan to add more side dressing applications every four to eight weeks.

Consider more frequent liquid fertilizer applications if your soil has serious nutritional deficiencies. These applications give your plants small boosts of nutrients.

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Growing a large yield of potatoes takes time, patience, and plenty of fertilizer for potatoes. These are some of the top potato fertilizers for your home vegetable garden. Be sure to try one this year!