What Is The Best Fertilizer For Growing Potatoes?

Have you grown potatoes in the past and they turned out very small?

If the answer is yes, then there will be a few reasons why this happened – there is one glaring mistake which many people dont realise – because you haven’t added enough fertilizer to the soil.

Potatoes need fertile soil to grow successfully – if you skip this your crop will suffer.

But even more important – if you add fertilizer in large amounts of the wrong nutrient like nitrogen (potatoes do not need large amounts of nitrogen) then you will actually damage the crop)- more on this in another article.

What type of fertilizer?

Choosing what is the best fertilizer for growing potatoes is a matter of personal preference. There are many different ways you can help your potatoes to grow, you can choose the organic route or standard chemical fertilizer.

Whichever way you choose to fertilize your crop (and you will need to apply some type of fertilizer to grow a good crop of potatoes) you need to decide if you are going to apply your fertilizer in a general way or if you want to add it in a specific way.

Adding farmyard manure/ compost for potatoes

For those who want to add fertilizer in a general way I would recommend adding a wheelbarrow of farmyard manure or compost per m2 in autumn and digging it in well and let it sit until spring when you can rototill it to a fine tilth before planting.

I have an article on homemade fertilizer for potatoes.

How to grow potatoes

For those looking for an in depth article covering all aspects of potato growing please visit my article How to grow potatoes.

More Specific Knowledge

For those who want to apply more specific knowledge to adding chemical fertilizer, the first thing you should do is to carry out a soil analysis. This begins by collecting a soil sample and either testing it yourself using a kit bought online, or by sending in your sample to your local Department of Agriculture for them to analyse.

Collecting your soil sample

To take your sample in a small area (less than a couple of m2) you simply dig down 4-6 inches and grab a handful of soil.

For larger areas you make an imaginary x from corner to corner of your plot and take a handful every few steps along the two lines.

Mix these sub samples together and take one sample from it. This will mean your small sample is made up of lots of small parts from all over your plot.

Reading Your Soil Analysis Report

When you receive your soil analysis results or complete your test you will have figures which relate to the amounts of Nitrogen (N) Phosphate (P) and Potash (K) which are present in your soil.

Now you have real data on how much of these nutrients are present, you should then consult the fertilizer manual i have linked to below to find out how much more of these nutrients you need to add to your soil for the crop you have chosen to grow.

These fertiliser articles are very useful reading. https://www.ers.usda.gov/topics/farm-practices-management/crop-livestock-practices/

Here is some information on a soil analysis test: https://efotg.sc.egov.usda.gov/references/public/WI/Soil_Quality_Test_Kit_Guide.pdf

This is typical of the layout of the soil analysis report you receive.

Figure 1–22. The main components of a soil test report.

Using this report you will be able accurately apply the correct amount of nutrients for the crop you have chosen.

Recommended potato fertilizer

The fertilizers i have listed below are higher in P and K which is essential for the proper development of your potatoes. Simply scatter the fertilizer over the ground which you will plant the potatoes into before you drill it up and you are good to go.

Winchester Gardens NPK 6-3-9 Select Organics Potato Granular Fertilizer, 3-Pound

$15.45  in stock
1 new from $15.45
Free shipping
as of January 22, 2020 11:07 pm


  • NPK Composition: 6-3-9
  • Great for sweet potatoes, bakers, boilers and reds
  • Encourages all-around growth
  • Includes spoon
  • 3 Lbs. package

Voluntary Purchasing Group Inc. 32145 4 lb. Muriate Potash

$13.78  in stock
14 new from $8.73
as of January 22, 2020 11:07 pm


  • Muriatic of potash
  • High yield formula
  • Excellent source of potassium
  • Four pound bag
  • Helps grow delicious potatoes and carrots

5 Pounds - Potassium Sulfate - Sulfate of Potash

$16.49  in stock
3 new from $10.99
Free shipping
as of January 22, 2020 11:07 pm


  • A good source of potassium and sulfur
  • Shipped in a resealable bag that is sealed for safety and freshness. It includes a tear-off tab for easy opening.

Organic Potato Fertilizer

$30.00  in stock
1 new from $30.00
as of January 22, 2020 11:07 pm


  • 3 lbs. Organic Potato Fertilizer
  • All-Natural & Non-GMO Sourced Potato Fertilizer (3-6-6).
  • 3 lbs. will feed 30 potato plants for an entire season.
  • Guaranteed to increase yields, size, health and vigor of your potato plants.
  • Derived from: Fish Bone Meal, Gypsum, Blood Meal, Alfalfa Meal, Sulfate of Potash & Feather Meal.

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