8 Best Fertilizers for Potatoes (Updated Reviews for 2023)

From all-natural and fast-acting to protein and granular, explore the best fertilizers for a bountiful potato harvest. We’ll also teach you the ideal fertilization time and process to achieve the best results.

By
Sean Stratton | Updated January 4, 2023

Fertilizers with a balanced NPK ratio, such as 15-15-15 or 10-10-10, are the best choice for potatoes in the first 2 months. NPK is the percentage of Nitrogen, Phosphorus, and Potassium in the soil.

The necessary NPK ratio will change throughout the potato plant’s 3-4 month growing season. After your potatoes are established (about 4 to 8 weeks after planting), you’ll need to fertilize them again with a fertilizer high in Nitrogen.

Then 4 to 8 weeks before harvest, fertilize once more. This time use a fertilizer higher in Potassium.

potatoes in a basket

1. Southern Ag All Purpose Granular Fertilizer 10-10-10

Southern Ag All Purpose Fertilizer is a great granular option if you plan to plant new potato plants. It has a balanced NPK ratio of 10-10-10, which is ideal for new plants.

The granular form is easy to spread throughout your garden, and the nutrients get directly infused into the soil when watered.

All its rich contents act as natural regulators for growth. Hence they promote rapid cell division. That way, you can fertilize your spuds for an entire season with just a 5lb bag.

Pros:

  • Even application without hassle.
  • NPK composition is 10-10-10.
  • Presence of max vital micro and macro elements.
  • Uniform, gritty formula utilized.

Cons:

  • It will not work well for your potted plants.

Next Read: Fertilizing Guide for Potatoes per Acre

2. Espoma Organic Bone Meal – For Bulbs & Other Plants

Are you looking for a potato plant food that works well to develop a robust root system and promotes healthy plant growth? This Espoma bone meal is the very best choice for you. It’s a scientifically approved solution for organic gardening, which is safe for all plants.

If you want to raise the acidic level of soil and nourish them, add some phosphorus and calcium, also available in this fertilizer. This is a slow-release fertilizer. It may take time to show the result, but it works effectively. To get the expected result, apply it to the soil at planting time.

Pros:

  • 100% organic; no fillers or additives.
  • Great natural source of high phosphorus.
  • Dissolves in water easily.

Cons:

  • Smells like soup; may be attractive to dogs.

3. Jobe’s Fertilizer Spikes, Vegetable Fertilizer

Do you want a fertilizer all in one place that protects your potatoes from unnecessary diseases and insects, resists drought, and improves soil quality? Then, Jobe’s organic fertilizer is an excellent choice for you.

It’s a non-synthetic supplement that is OMRI listed and permitted for organic use by the USDA (United States Department of Agriculture). This is recommended for potatoes and tomatoes, onions, cucumbers, beans, carrots, and many more vegetables.

It contains Jobe’s Biozome, an ideal combination of Mycorrhizal, Archaea, and healthy bacteria. This ingredient will provide the long-term benefit of promoting a healthy ecosystem.

These fertilizer spikes are time-release, and supply nutrients steadily to get healthy potatoes. They are neat little bullet shapes and pretty easy to use. Just push them below the soil and then cover the spot. Consider applying it in the growing season.

Pros:

  • Non-synthetic organic fertilizer.
  • Improves soil conditions.
  • Fight against disease and pests.
  • Environmentally safe.

Cons:

  • Keep the spikes away from children.

4. Winchester Gardens NPK 6-3-9 Potato Fertilizer

Being root vegetables, potatoes thirst for proper nourishment in the stalks, roots, and stems under the soil. Isn’t it? The Winchester Gardens spud food can do the nourishing magic.

It comes in a packet of 3 pounds with a fusion of specially picked elite organics. Thus, it aims to boost the growth of sweet potatoes, boilers, reds, and bakers beneath the soil. Its all-natural factor formula thrives on overall nutrition and progress.

One of the top entities you look for in the manures is the NPK ratio. Why? Because it indicates the percentage of essential food elements present in the fertilizer.

The Winchester brings you an NPK composition of 6-3-9. It means 6% Nitrogen, 3% Phosphorus, and 9% Potassium combines to form this special organic manure.

No need to worry about the application process. It’s as easy as a breeze. Follow the guidelines in the packet behind you and use the spoon included to apply!

Pros:

  • Easy to apply granular fertilizer.
  • Enhances growth with NPK 6-3-9.
  • No harmful elements are included.
  • Designed to enrich soil quality.

Cons:

  • You’ll need to wait to see the results.

5. Dr. Earth Home Grown Vegetable Fertilizer

When growing larger and the healthiest potatoes, try Dr. Earth’s organic fertilizer. It is enriched with different variations of macrobiotics, beneficial probiotics, humic acid, fishbone meal, fish meal, and alfalfa meal; all of these are very effective in growing healthy potatoes.

This blend is organic certified by OMRI, NOP, OIM, and the CCOF (California Certified Organic Farmers). The NPK ratio of this supplement is 4-6-3. It has more phosphorus than nitrogen and potassium. High phosphorus helps to promote root development.

Pros:

  • 100% organic, hand-crafted blend.
  • Highest level of purity and transparency.
  • Slow-release fertilizer.

Cons:

  • The scent can attract your dog, so be careful.

6. The Old Farmer’s Almanac Organic Vegetable Plant Food

Do you want to get rich-colored, healthy, and delicious potatoes for your family? Then the Old Farmer’s Almanac plant food is for you. It’s a very powerful and high protein-based nutrient to ensure healthy plant growth.

This natural granular fertilizer is OMRI listed and safe for potatoes, tomatoes, fruits, vegetables, herbs, shrubs, and trees. The NPK ratio is 8-4-8. These three necessary nutrients primarily help to get solid roots and faster growth.

It’s derived from all-natural bone meal, blood meal, feather meal, soybean meal, and more. This can be applied to almost all types of plants. However, follow the instructions on the packet for the ideal application.  

Pros:

  • No harsh chemicals or offensive smells.
  • Applicable for indoor and outdoor plants.
  • Slow-release fertilizer.

Cons:

  • Better not to use this for your herb garden.

7. Jobe’s Organics 09526 Organic All Purpose Fertilizer 4-4-4

Jobe’s All Purpose Organic Fertilizer is one of the best organic fertilizers for root vegetables like potatoes.

This granular plant food lasts longer than its liquid counterparts, so you don’t need to fertilize your potatoes as often. It also has an equal NPK ratio of 4-4-4.

The most surprising addition to the manure is Jobe’s Biozome. It’s a microbe that quickens the breaking down of elements below the soil. This process helps the plant’s health and resistance to diseases, insects, and drought! 

Pros:

  • 100% Organic with no trace of synthetic chemicals.
  • Contains a Biozome microbe for faster-growing potatoes.
  • Fights plant diseases; eco-friendly.

Cons:

  • More expensive.

8. Easy Peasy Urea Fertilizer – 46-0-0 Plant Food

Are you searching for a fast-acting fertilizer for potatoes? Pick this urea fertilizer. This fertilizer is rich in nitrogen with an NPK ratio of 46-0-0. The high nitrogen levels are optimal for fertilizing your potato plants 1 to 2 months after planting.

This fertilizer is best for potato plants with established roots because it helps the potatoes grow faster. The large packets are easy to store and has enough fertilizer for several applications.

Pros:

  • High in nitrogen.
  • Safe for flowers, turf, and gardens.
  • Fast-acting fertilizer.

Cons:

  • Overusing can burn your potato plants.

Considerations when Buying Fertilizers for Potatoes

There is an overwhelming amount of fertilizer products on the market today. Consider the following when searching for the ideal fertilizer for your needs:

Types of Fertilizers: Generally, when you purchase potato fertilizer, you have two standard options to choose from; liquid and granular.

  • Granular fertilizers look like small dry pellets. This fertilizer type is easy to apply and has a longer shelf life. The slow-release granules can release nutrients to your plants over an extended period of time, so you don’t need to fertilize as often. Granular fertilizers are usually cheaper than liquid fertilizers.
  • Liquid fertilizers come in a liquid form that must be diluted with water. It’s a fast-acting fertilizer with a larger concentration of nutrients. The soil quickly absorbs the liquid for fast results, but the fertilizer will need to be applied again as the results don’t last as long as with granular fertilizers. However, it’s an excellent choice for dying lawns that need instant action. Liquid fertilizers are a little more expensive than granular.

Organic or Non-organic fertilizers:

  • Organic fertilizers are made from natural ingredients such as compost, leaves, seaweed, cow manure, etc. They provide nutrients slowly but effectively. This slow process can reduce nutrient leaching risk. Organic plays a significant role in improving soil structure and quality.  These fertilizers may have an unpleasant smell, and the application process can be messy.
  • Non-organic fertilizers are synthetic and manufactured from chemicals. They quickly release nutrients into the soil. They’re fast-release plant foods, though slow-release options are also available. The products are simple to use, but over-fertilizing can be harmful.

Amount of Nutrients: Before buying any fertilizer for potatoes, you should test the soil. It will help to find out the soil’s acidity, the exact absence of nutrients, and how many nutrients they require. There are a few nutrients that are generally helpful when growing potatoes.

  • Nitrogen
  • Phosphorus
  • Potassium
  • Magnesium
  • Manganese
  • Boron

The NPK Ratio: Consider buying a fertilizer with an ideal NPK ratio. It’s very important for a fast and healthy growing process. NPK means the amount of the three necessary nutrients – nitrogen (N), phosphorus (P), and potassium (K). The NPK ratio of 15-15-15 is suitable for planting time.

After a month or two months of planting, potatoes highly require a fertilizer rich in nitrogen. So a supplement of a 34-0-0 ratio is ideal for this time. They need more potassium in the last couple of months before gathering crops. Choose the right fertilizer according to your plant’s needs.

Soil PH: Potato plants perform well in acidic soil. The soil pH should be between 4.8 and 6.5.

  • If your garden soil has a lower pH level, add some gypsum to increase the level.
  • If the soil pH is too high, consider buying a fertilizer that contains manganese or sulfur. You can also add lime to keep the pH low.

Amount of Fertilizer: The amount of fertilizer needed depends on the size of your planting area and the soil quality. As a rule, they typically need 25 to 30 pounds of fertilizer for 1000 square feet.

Also Read: Can You Use Cow Manure for Potatoes?

Frequently Asked Questions

Potato plants receive energy from sunlight and a subtle range of minerals from water. But do you think that is all a tuber plant needs in its growing stage?

Fertilizers are food for plants. They provide the proper ratio of macronutrients for your potatoes and help replace the nutrients your soil lacks. These macronutrients each play an essential role in growing potatoes:

  • Nitrogen (N): It drives the healthy growth of stems and leaves in potato plants.
  • Phosphorus (P): It helps the development of the root system. A lack of P causes the leaves to get darker.
  • Potassium (K): It keeps the roots healthy and raises the tuber’s storage ability boosting tissues. Thus it prevents black spot formation.

Apart from the prime ones, the other minerals that aid your tubers progress are:

  • Boron: It gives your potatoes soft skin and helps absorb calcium.
  • Magnesium: It enhances the metabolism of potato plants.
  • Manganese: It helps to keep a proper soil pH for tuber production.

Most gardeners lack the idea of the time to harvest and fertilize potatoes. They focus more on how to fertilize than the time and season. As a result, they fail to get healthy plants even after a long time of planting.

So before learning how to fertilize, let’s first know when to fertilize spuds:

  • Are you done with planting and two weeks over? Then it is time you were looking to start fertilizing your tubers.
  • Time to water!!
  • We would advise continuing the use for four weeks in the same way.
  • Add water that gives the fertilizer an easy way to soak up in the soil.
  • About to harvest in the next two weeks? It is time to halt your potato fertilizing.
  • The last two weeks claim no watering at all.
  • Fertilizing time ends here!

The basic dose of potato fertilizer application is divided into four steps. Have any clue? Let us uplift your concepts on fertilizing!

1. Before planting: Preparing the soil with vital nutrients is necessary before planting your potato seeds. So spread the fertilizers at a gap of 2 weeks that contains more Nitrogen. Make sure the soil is not extra wet and absorbs max amount.

2. After passing one month of potato planting: We would ask you to 0.2 tons per hectare. In this case, use mulch with a balanced NPK for optimum results.

3. After passing two months of potato planting, tubers need more Nitrogen and Potash than phosphorus at this stage. So pick a food plant with N and K level greater than P. Add half a ton per hectare.

4. After passing three months of potato planting: Most potatoes start their growth by this time. So, mix another half a ton of fertilizers in this time frame with a suitable NPK.

Are you aiming to grow big potatoes, adding fertilizers? Great! But how? Why not follow our expert growers’ advice:

  • Keep the potato seedling 36 cm apart
  • Adding a decent distance allows the tubers to soak more nutrients along with water
  • Make sure to use fertilizers at a regular intervals as suggested by your manual
  • Water daily, but you better neither keep it too dry nor too wet

To promote healthy growth with green leaves and quality tubers, container-grown potatoes need many nutrients. Nutrients leach out of the container due to watering. That is why they require more fertilizers than in-ground plants.

Organic and chemical fertilizers both are good for potatoes. The important thing is to look for a fertilizer containing a balanced ratio of nitrogen and phosphorus. These macronutrients promote healthy green foliage and tuber growth.

Be careful to use accurate measurements for your fertilizer. It is unlikely to harm your plants if you over-fertilize or accidentally pour more organic fertilizer than needed. But overusing chemical fertilizers can lead to damage.

Potatoes need fertilizers to grow well and abundantly throughout their growing season. Your fertilizing schedule should start after planting potatoes though some gardeners suggest starting fertilizing before plantation.

The ideal time for the first fertilization application is 2 weeks after planting. Then reapply for 1-2 months as needed. Avoid fertilizing 2 to 3 weeks before harvesting.

The size of your potatoes can be affected by not enough sunlight, inadequate supply of water, a flawed drainage system, deficiency of vital nutrients, and improper fertilization.

Low-quality potato seeds can also be responsible for getting small potatoes. Avoid planting potato seeds too close and plant them at a safe distance from taller plants.

Yes, eggshells are suitable for growing potatoes. The shells contain more than 90% calcium carbonate, minerals, and other nutrients such as magnesium, potassium, and phosphorus. These nutrients improve soil quality, root growth, and overall plant condition.

Eggshells can also control the pests in your potato gardens, such as snails, slugs, ants, beetles, cutworms, and other crawling pests.

They take a while to decompose, so you can fertilize your next year’s plants with the same eggshells.

Yes, lime can make the soil less acidic and more alkaline. But before applying it, you should test your soil’s pH to ensure that lime is needed. Potatoes are acid-loving plants. They prefer acidic soil with a pH between 5.00 to 6.5. If the soil is too acidic, consider applying lime to increase the pH level and add the necessary nutrients.

Lime contains magnesium carbonate and calcium carbonate. They release beneficial microbes and bacteria into the soil and supply nutrients such as zinc, and phosphorus to maintain soil quality and promote plant growth.

Coffee grounds contain many crucial minerals such as nitrogen, phosphorus, potassium, calcium, iron, and magnesium. It provides essential nourishment and increases the growth of potatoes.

The caffeine content of coffee gives a bitter odor, that can be used as an organic pest deterrent. It deters snails, slugs, fruit flies, and beetles.

Take care not to overuse coffee grounds in your garden. Coffee grounds should only comprise 10 to 20 percent of your soil.

Final Thoughts

We have prepared a list of our top choices for potato fertilizers, now it’s your turn to pick the right one according to your necessity.

Written by Sean Stratton

Sean Stratton

Hi, I'm Sean, the senior editor here at Fertilizer Pick. I grew up on a farm in North Carolina and have grown fruits, vegetables, and trees since childhood. While I no longer live on a farm today, I still enjoy spending time on my garden and sharing my knowledge with friends and fellow garden enthusiasts.