potatoes grown in drills with green tops and sandy soil

What Is The Optimum Soil PH For Growing Potatoes

If you’re looking for a crop to add sustenance to your vegetable garden, look no further than the mighty potato. Potatoes have been a dietary staple for centuries because they are easy to cultivate and give high yields in small amounts of space. Discover later in this article what is the recommended soil pH for potatoes.

If you’re planning on growing potatoes, it’s important to know the pH of your plot and try to make your soil slightly acidic if it isn’t already. Keep in mind that this process doesn’t happen overnight and it’s best to start preparing the area where you want to plant potatoes the year before.

Although amending the pH of your soil is pretty easy to do, it requires time, patience, and precision. Start planning for this simple but lengthy process by reading this article to learn what the best soil pH is to grow potatoes and why it is important.

What is the optimum soil pH to grow potatoes?

The optimum soil pH to grow potatoes is from pH 5.0 to 6.0. Potatoes will tolerate being grown in soils with extreme pH as low as 4.5 and as high as 8.0 but the crop will suffer. Potatoes grown in soils with a pH of 7.5 and above will experience a lack of phosphorous uptake and other micronutrients, even though they are present in the soil. Common scab can also be more of an issue in highly alkaline soils. Low pH acidic soils will also restrict phosphorous uptake and molybdenum – resulting in young plants with yellow leaves.

Potatoes need a little bit of special attention because they are heavy feeders. Normally potato growers ensure lots of fertilizer is available throughout the growing season to make sure their potatoes have enough nutrients. All the compost in the world doesn’t matter though if you don’t have the right soil pH. Alkaline soils, for example, will prevent plants from absorbing the nutrients so it won’t matter how much you fertilize.

If the soil pH is too high, the chances of your potatoes developing a disease called ‘potato scab’ increase exponentially. Scab is a soil-borne disease that disfigures the potatoes. It isn’t normally a problem in acidic soils, but if your soil is higher than a pH of 7, make sure to plant scab-resistant potato varieties.

potato field with healthy potato tops and drills
Getting your soil pH correct will reward you with a great crop of potatoes

Keeping the soil where you’re growing potatoes between a pH of 5.0 and 6.0 is ideal. This will give your potatoes the best conditions where they can uptake all the available nutrients and you can prevent annoying diseases. Amending your soil to be slightly acidic is a simple procedure that will make your potato growing experience so much easier.

How do I know the pH of my soil?

If you’re not sure what the soil of your pH is you can quickly and easily do a pH test. You can either use litmus paper (the cheapest option) or buy a pH testing kit.

If you’re not sure whether gardening is for you, go for the litmus papers. They are cheap and easy to use but don’t give you a super precise reading. You’ll have a general idea of the pH rounded to the nearest whole number, but you won’t know if it’s 5.1 or 5.5, for example.

If you think you’ll want to test your soil more than once, consider buying a pH testing kit. You can pick up a proper pH testing kit from your gardening supply store. It’s a little bit more of an investment but you will gain so much knowledge about your soil that it’s worth the investment.

What will happen if my soil does not have the correct pH

If your soil is not at the correct pH your potatoes won’t thrive. Soil pH is particularly important for potatoes because it facilitates the uptake of nutrients and prevents certain diseases.

Growing potatoes at a neutral pH will still give you an average yield. But if you want to provide the best conditions for the healthiest plants that will give you the highest yields, it’s well worth the trouble to achieve the right soil pH.

You’ll only have problems if your soil is too alkaline (above pH of 8) or much too acidic (below pH 5).

If you’re not convinced, experiment. Try growing the same varieties of potatoes in acidic, neutral, and alkaline soils and see for yourself how the pH affects the vitality and immunity of your plants.

What should I add if it is not the correct pH

To make your soil more acidic you’ll need to lower the pH. In order to do this amend your soil with agricultural sulfur which is available in many garden supply stores. You’ll want to use varying amounts of sulfur depending on your soil type. Keep in mind that you’ll want to wait at least a month before planting to avoid burning your plants, so plan accordingly.

If your plot is too acidic and you need to make your soil more alkaline add some wood ash or agricultural lime. I like amending with wood ash because it’s easily available and has other benefits for the soil. If you’re using lime, you need a more thorough soil test to know how much to add so you don’t overdo it.

Be careful when adding any amendment to your soil. It can be very easy to put too much and make the soil too alkaline or acidic for potatoes. Start with small quantities of the amendment and test the pH again before planting to make sure it’s in the right range.


Potatoes are an amazing crop to grow in your garden because they can be a major source of sustenance. They are incredibly productive for the amount of space they occupy and they can be stored for many months. Plus, growing your own potatoes will provide you with stunning varieties that you could never find at the supermarket.

These qualities make potatoes an important crop for anyone wanting to grow their own food. The key to growing healthy and prolific potatoes, however, is making sure your soil has a pH between 5.3 and 6.