What is the Ideal Soil pH For Potatoes? Know the Facts!

Are you looking for a way to obtain a higher potato yield? Then good news because here, I am telling you a secret for Top-notch potatoes yield. No, it is not the application of fertilizers or any other overrated products there are in the market. The single thing which you should do if you want to successfully cultivate potatoes is taking care of the soil pH. Yes, you read that right!

An optimum pH for Potatoes is the key factor in determining the production and quality of potatoes.

So, what is the best soil pH for potatoes? (The answer is the same for both indoor and outdoor growing). Moreover, I will also be telling you about the ways you can increase and decrease the pH of the soil.

Have a look at the table of contents to see how this article might be the most informative thing you will read today.

What is the Ideal Soil pH for Potatoes?

There is a reason why people ask What should be the soil pH be for potatoes. Potato has a critical relation with pH because nutrient uptake depends on it.

Those who are growing potatoes for years know that this vegetable’s requirements are a little different than the rest of the vegetables. Potato soil requirements must be fulfilled if you want to end up with a high yield. Potatoes need soil that is fertile, well-drained, and slightly acidic in nature. Don’t expect to have top-quality potatoes If the soil is neither fertile nor well-drained. The potatoes grown in such soil will have an irregular shop and also tuber rot.

Moreover, Potato requires more nutrients (fertilizers) than other vegetables to fully achieve the yield potential. If the pH is above or less than the optimum range, then nutrient uptake will not occur and the plants will be weak with poor yield.

So, what are the pH requirements for potatoes for excellent yield?

According to the University of Maine, the ideal soil pH for potatoes is between 5.3 to 6 (slightly acidic). A grower should not settle for more or less than this soil pH range for potatoes cultivation.

If you want an exact value, then 6 is the optimum pH for potatoes. It can still tolerate the soil pH of up to 5. Below 5 won’t produce any top-quality potato. Similarly, the highest ever pH a potato can tolerate is 8 (alkaline). If the soil is alkaline, the chances of Potato Scab disease increase too.

pH for Potatoes
Potatoes growing in the soil

How to Do a Soil Test for Acidity?

It is necessary for you to know about the soil pH. For this, you should do a soil pH test to check whether the acidity of the soil is in desired range or not.

Begin by taking soil samples from 10 different parts of the field/potting soil and then mix them together in a container. Now take out the pH testing kit or pH meter and follow what is written on the instructions label on the box (different types of equipment function differently). If it doesn’t show pH between 5.3 to 6, then it is time to take some measures.

pH for Potatoes
pH test for potatoes

How to Adjust pH for Potatoes?

If you are lucky, then the soil test will show the pH of the soil is optimum for potato growing. Sadly it’s not the case most of the time and to have the best soil pH, you have to adjust it with some amendments.

Before applying any amendment, you have to loosen the soil first. Use shovel or tiller for this purpose. Then take the following measures to increase or decrease the pH according to the requirement.

How to Increase the Soil pH for Growing Potatoes?

If the pH of the soil is less than 5, then start some treatments to reduce the acidity.

1) One way to reduce acidity is the application of wood ash. Apply 10-15 pounds of wood ash per 100 square feet, and then mix it in the soil.

2) You can also add lime to reduce the acidity of the soil. Add 5-10 pounds of lime per 50 square feet and then stir it deep in the soil up to 6 inches.

Lime and wood ash helps optimum ph for potatoes
Lime and Wood Ash reduce Acidity

How to Decrease the Soil pH for Growing Potatoes?

If the soil pH level for potatoes growing is more than 6.5, then apply the following amendments for lowering soil pH for top quality cultivation:

1) To decrease the pH, one effective amendment is horticultural sulfur. You can easily purchase it online or from any store that sells gardening-related products. Add one and a half-pound of horticultural sulfur per 100 square garden feet. This application will reduce the pH from 7 to 6. If you want to reduce by 0.5, then reduce the application in half. The amendment should go 8 inches into the soil, so Mix it with the help of equipment like a tiller.

2) You can also use Sphagnum moss to increase acidity. Similarly, You can also add Phosphoric acid for the same purpose too.

lowering soil ph for potatoes
Sphagnum Moss

Amending soil pH is not a quick process and it may take up to six months. So, do this in the fall and let the rest soil till the next growing season. Also, don’t grow anything within this time period. In the next growing season, do the soil test again to confirm that the pH is now in the desirable range.

Those who search for the ideal pH for growing potatoes also search for other vegetables too.

Optimum pH Levels of Other Vegetables

For those who also want to know about sweet potatoes, tomatoes, carrots, corn, and other vegetables, then this part is for you.

Sweet Potato Soil pH:

People search, what is the optimum pH for growing sweet potatoes? The sweet potatoes show decent results when grown between 5.6 to 6.8 soil pH. But, the ideal soil pH for sweet potatoes is between 5.8 to 6.

Soil pH for carrots:

The optimum soil pH for carrots cultivation is between 6-7. Carrots can be grown in those soils having a slightly acidic to neutral pH.

Soil pH for Corn:

The optimum soil pH for corn is between 5.8 to 6.2.

Soil pH for Tomatoes:

People who want to grow tomatoes should know that The optimum soil pH for tomatoes is 6 to 7.

Soil pH for Vegetables (Chart)

Check out the ideal soil pH for different vegetables!

VegetableIdeal Soil pH
Beans6.0-7.5
Cabbage6.0-7.5
Spinach6.0-7.5
Brocolli6.0-7.0
Turnip6.0-7.0
Lettuce6.0-7.0
Pumpkin5.5-7.5
Cucumber5.5-7.5
Cauliflower5.5-7.5
Garlic5.5-7.5

The end product or vegetables itself has a pH value. The different food products of potatoes show the same pH as the soil they are grown in. The potato pH level is 5.6-6 (very similar to the soil pH). Potato pH value also has an impact on how it tastes. The pH of potato juice is between 5.8 to 6. However, due to processing, the pH of potato chips is 3. Similarly, the sweet potato pH level is 5.3 to 5.6 and the list goes on!

Final Thoughts

All-inclusive, you should ensure the ideal pH for potatoes to have extraordinary yield. The best pH for potatoes for smooth growing is 5.3 to 6.0. To know about the pH condition of the soil, do a soil test. You can either use a pH meter or strips to measure the current pH scenario.

If the pH is above or below the optimum levels, then you must add amendments. If it is high, then add horticulture sulfur, sphagnum moss, or phosphoric acid. If it is low, then add lime or wood ash. But the change in the pH value won’t happen overnight. You will have to wait for the whole season to bring the pH to the optimum levels. So, plan right now about what your soil have next season!

FAQs About Ideal Soil pH for Potatoes

How do you acidify soil for potatoes?

You can acidify the soil by applying horticultural sulfur, sphagnum moss, and phosphoric acid. Moreover, ammonium-based fertilizers also increase acidity.

What is the best fertilizer for potatoes?

Potatoes need less nitrogen than phosphorus and potassium. So, the best fertilizer should have less nitrogen, and twice more potassium and phosphorus for potatoes’ smooth growing (in ratio 5:10:10 ).

How do I lower the pH in my garden soil for potatoes?

People ask how to adjust pH for potatoes and the answers are pretty simple. You can lower the pH of the soil by adding lime, wood ash, or any other substance that is alkaline in nature. Generally, lime is preferred by gardeners as it does not cause any harm to the soil or plants.

Can potatoes grow in alkaline soil?

Potato soil requirements are complicated as pH and drainage should be optimal. Potatoes can grow in the alkaline soil of 8 pH but that quality will be extremely bad. Potatoes will be of irregular shapes and will look like they are diseased.

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I am a graduate in Agriculture Sciences and have been doing gardening for over 7 years. I am also a professional and certified Article & Blog Writer. I am happy to share my years of experience in gardening with all of you through my writings. In addition to this, I do extensive research on every topic to enrich readers with valuable knowledge.