What Kind of Soil to Grow Potatoes? (Plus How to Prepare)


Are you are planting potatoes for the first time, or have you had trouble growing them in the past?  If so, then you’re not alone.

Many gardeners wonder what type of soil is best for growing potatoes.  Having the right soil for your potatoes will make for a much better harvest at the end of the season.

So, what kind of soil to grow potatoes?  Potatoes grow best in loose soil that drains well (such as sandy loam).  Potatoes grow best in soil with a pH of 4.8 to 5.4.  It is a good idea to add some organic material to the soil (such as compost or aged manure) to help potatoes grow better.

Of course, there are ways to improve your soil if it does not exactly fit the profile described above.  Let’s get into more detail about what kind of soil you need to grow potatoes and how to prepare your soil for growing potatoes.

What Kind of Soil to Grow Potatoes?

According to the University of Georgia Extension, potatoes grow best in soil that is loose and drains well.  Usually, this means sandy loam soil.  Potatoes also prefer slightly acidic soil, with a pH of 4.8 to 5.4.

Soil Consistency

If your soil sticks together and you can mold a handful into different shapes (like clay), then you have clay soil.  Clay soil holds lots of water because it does not drain well.

clay soil
Clay soil: not the best for growing potatoes. Add some compost to improve the structure and loosen it up.

Clay soil is also very dense and tightly packed.  Since potato tubers form underground, clay soil makes it hard for potatoes to grow.

To improve your clay soil for growing potatoes, add some compost or aged manure.  This will make the soil drain better, loosen up the soil, and also add some nutrients.

Remember: you should not add sand to loosen up clay soil.  The result will be very hard soil that will be difficult to work!

On the other hand, if your soil is loam (not clay), but not as loose as you want, then you can add a little sand to the soil.  Potatoes, carrots and other “root” crops prefer looser soil, which allows them to grow without bumping into dense clumps of soil.

If your soil is too sandy, then it will drain very quickly.  This can lead to a lack of water for any plants you try to grow, including potatoes.  If your soil does not hold its shape and dries out very quickly, then you probably have sandy soil.

sandy soil
Sand may drain too quickly, leading to a lack of water for your potato plants.

No matter what type of soil you have, you can improve it by running it through a sifter.  This will remove rocks, roots, soil clumps, and other debris from your soil.

You can make a soil sifter from some wood, some chicken wire with small holes, and some nails.  You can also buy a soil sifter online if you are not handy at building things.

Soil pH and Nutrients

The ideal soil pH for growing potatoes is 4.8 to 5.5 (somewhat acidic).  If you are not sure about the pH of your soil, get a soil test.

You can buy a home soil test kit online or from a store.  Another option is to send a soil sample to your local agricultural extension for testing.  If you want to learn more about these options for getting a soil test, I’ve written an article all about it here.

A soil test will tell you the pH of your soil, and it will also tell you about the nutrient content of your soil.  The “big three” nutrients are nitrogen, phosphorus, and potassium (NPK).

A soil test may reveal that one or more of these nutrients is lacking in your soil.  In that case, you may want to use fertilizer as you prepare your soil for planting potatoes.

How Do You Prepare the Soil for Planting Potatoes?

Even if your soil is not ideal for growing potatoes, there are still some steps you can take to turn things around.

Compost

Compost will help to improve most soil types – not just clay soil.  Compost contains organic material and nutrients.  Compost helps to build the structure of the soil while also feeding plants.

compost bin
Compost makes clay soil drain better and adds nutrients to the soil.

In addition, compost encourages the growth of beneficial soil organisms, such as bacteria and worms.  These organisms aerate the soil and break down leaves, grass, and other debris into a form that plants can use to grow.

Compost is a great way to keep your soil healthy.  The best part is that you can make compost from yard and kitchen scraps that you probably already have lying around.  If you want to learn more about how to make compost, then check out my article all about compost.

Crop Rotation and Cover Crops (Green Manure)

Crop rotation means that you plant different crops in the same location every year.  For example, in one corner of your garden, you might plant potatoes in year 1, beans in year 2, corn in year 3, and so forth.

Crop rotation helps to avoid the spread of disease in your garden.  It also helps to prevent soil depletion by growing different crops each year and replacing nutrients in the soil.

Planting a cover crop (also known as green manure) is another way to improve your soil between growing seasons.  A cover crop is one that you plant and grow in the garden to help replace nutrients that have been used and depleted by other crops.

For example, you would plant a cover crop, such as alfalfa (Lucerne), in your garden after the growing season end.  The alfalfa has deep roots, and will pull up nutrients from deep underground.

alfalfa
Alfalfa (lucerne) is one good cover crop that is useful as a green manure.

After the alfalfa grows, you would till it into the soil and let it decompose.  The nutrients in the alfalfa would then become available to the crop you plant in the soil next year.

If you want to find out more about the crops you can use for green manure, you can read more here.

Fertilizer

Compost and cover crops can help to replace some nutrients in the soil, but sometimes fertilizer is necessary.  This is especially true if you are growing “heavy feeder” crops that use up lots of nutrients in the soil.

As mentioned earlier, a soil test will help you to figure out which nutrients you need to add to your soil.  A balanced fertilizer, such as 10-10-10, will add some of each of the “big three” nutrients (nitrogen, phosphorus, and potassium) to your soil.

No matter which fertilizer you choose, always follow the instructions on the package to avoid burning your plants by over fertilizing.

If you want to learn even more about how to prepare for planting potatoes, check out my article here.

Is Chicken Manure Good for Potatoes?

Chicken manure is good for growing potatoes, since it contains lots of nitrogen, which helps potatoes to grow.  However, you need to make sure that the manure has been aged and allowed to decompose!

You should never use “hot” or fresh manure for growing plants.  Fresh manure contains too much nitrogen, and also some salts from animal waste.  Both of these things can burn your potato plants.

When using chicken manure (or any other manure) in your garden, there are a few guidelines to keep in mind:

  • Allow manure to age for 3 to 12 months to break down completely.  To make it decompose faster, turn it with a pitchfork or shovel every so often, and add water if it dries out.
  • Properly aged manure should look like soil.  You should not be able to see any sawdust, wood shavings, straw, or animal bedding in properly aged manure.
  • Mix manure with compost & soil before putting it in the garden.  This will decrease the concentration of nitrogen and salt in the manure.
  • If applying aged manure directly to your garden, use a thin layer that is 0.25 to 0.5 inches deep.

Can You Grow Potatoes in Potting Soil?

Yes, but make sure to adhere to the guidelines given above!  Keep in mind that sandy loam is best for growing potatoes.

Remember that potting soil is not all the same, and that you can add compost, aged manure, fertilizer, or sand as necessary to change the structure, water retention, and nutrient content of the potting soil mix.

How Deep Does Soil Need to Be For Potatoes?

According to the Oregon State University Extension, you should work soil to a depth of at least 6 inches before planting.  However, you also need to account for “hilling” during the potato growing season.

Hilling simply means adding extra soil to cover a part of the potato plant that has emerged from the soil, along with any tubers.  During the growing season, your hills might end up being as tall as 8 inches high!

So, it is best to make sure that your container is at least 14 inches deep if growing in a container.

Note: most of the potatoes you harvest at the end of the growing season will be found in the top 6 inches of soil.

Alternative Ways of Growing Potatoes

If you have limited space or want to try something new, there are some interesting alternative methods for growing potatoes, such as:

straw bales
You can grow potatoes in straw bales, or you can try raised beds or grow bags.

Conclusion

Now you know what kind of soil you need so that your potatoes will yield the best harvest possible.  You also know how to make a few key changes to improve your soil to make it ideal for growing potatoes.

I hope you found this article helpful – if so, please share it with someone who will find the information useful.  Now it’s time to get back to the garden and grow the best potatoes possible!

jonathon.david.madore

Hi, I'm Jon. Let's solve your gardening problems, spend more time growing, and get the best harvest every year!

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