how to hill up potatoes

How To Hill Up Potatoes: why and how to do it

What is “hilling up” potatoes

Gardening is always thought to be simple and easy, looking from the outside. This is the idea:

  • Plant the seed in the ground
  • Water.
  • Plant grows.
  • Pick your fresh produce.

However, once I got started, I realized very quickly that it just isn’t that easy.

Different plants need different amounts of water, sunlight and fertilizer. Gratefully, years later, I’m growing healthy plants and fertilizing enough to keep things looking good.

When I started planting potatoes, I quickly realized that as the potatoes grow in the soil, I need to mound them up with more soil to keep them covered if they become exposed.

This process of mounding soil around the potatoes is known as hilling up. In this article i will show you how to hill up potatoes and why it is important.

It turns out that in potato growing this is important, helping to ensure the grower that he isn’t going to hash brown some poison right into someones breakfast dish by serving up some green “sunburnt” potatoes.

How to grow potatoes

If you would like more information about growing your own potatoes, please read my article How to grow your own potatoes. This covers everything you need to know from planting, preparing seed, growing, harvesting and storage and more about this great vegetable.

Background and origin of otatoes

This method is called hilling, mounding, ridging, and earthing up to name a few.

Potatoes are native to areas in the south of South America and made their move to Europe with the Spanish conquerors in the 16th century.

From here, they spread across the whole of Europe and, because of their high carb content, became a staple in many people’s diets from then on.

Hilling has theoretically been around since the beginning, as people must have quickly figured out due to the cons of eating a green potato.

Preparing to plant potatoes

When i started growing potatoes, I discovered the importance of properly preparing for each step in the process.

What I begin with is preparing my seed potatoes. This involves using small potatoes or cutting large potatoes into approximately one-inch chunks so that there is at least one eye of the potato on each piece.

The eyes are where the stems will start to grow from, so getting a couple on each will increase the likelihood of getting a healthy plant from it while limiting the number of plants that will grow up and create a mess together.

I then let the potatoes air dry for a few days. The purpose of this is to allow the outside to toughen up a bit and therefore resist disease better. Then i store the seed potatoes away inside a shed until a short bud appears. They are now ready to plant.

I have found that potatoes are a bit picky when it comes to the type of soil they like to grow in.

To get the maximum amount of yield at the end of the season, I plant my seed potatoes in deep, loose, loamy soil which is rich in organic matter.

Many people recommend planting in a well-mixed compost and loam soil mixture and digging a shallow trench where your row is going to start, about 6 inches deep and about 3 inches wide.

Planting the potatoes

I plant the seed potatoes into the soil when the ground is warm enough (ground temp above 8°C or 46°F).Then, I plant the seed potatoes themselves about a foot away from each other as this will ensure room for them to grow and multiply inside the drill. Then i shovel the soil on top of the potatoes covering them with at least 6 inches of soil.

How to hill up potatoes

Now we get to the good stuff. As your potato stems begin to poke their heads above the soil, you still don’t need to do anything yet, just wait..

When the plant is about 8 inches tall, or 20 cm, now is the time to get ready to hill them up. I go ahead and grab my hoe and shovel and pull the soil on top of the plants. If the potatoes are in a grow bag or box, bucket or pot you can mound the potatoes with many different options. Including loose soil, compost, or mulch among others. If they are in a container you should add around 3 to 4 inches of compost or soil. Put it to the top of the container to help keep your growing potatoes covered.

If the potatoes are in a drill or a bed you may have weeds growing on them. If so, you should hoe the sides of the drills to remove the weeds. Be careful not to remove too much soil in case you uncover the growing potatoes.

Then using your shovel you should heap the earth from the bottom of the drill back up onto the top of the drill adding another extra 2 to 4 inches to the drill.

Why should I hill up or mound potatoes?

Now that we know how to hill up potatoes, you may be wondering why it is important to do.

Prevents green potatoes

Quick science corner, what makes a potato green is just the process of photosynthesis happening, the process required for our plants to grow.

When this greening begins to happen, the potato begins to become toxic. The green, from chlorophyll, is not the toxin, the toxin is solanine.

You can peel this green on the potato away. However, the peel only contains about thirty percent of the toxin. There is still a good chance you are going to have effects after eating it. The toxin solanine is the compound in the potato skin and flesh that causes you to be sick.

If you were to eat a lot of this green part of the potato you will feel sick and most likely vomit.

Not all the reasons why potatoes should be hilled up are bad, however.

Increased yield

One great reason to is that new potatoes can begin to grow larger when more new earth is added. This provides the plant with more nutrients and minerals allowing it to grow larger potatoes.

Blight protection

Another reason to hill up potatoes is to protect the newly emerging potatoes from blight. Blight can infect the leaves but you could save the potatoes before blight reaches them. If the potatoes are exposed they have a higher chance of being infected earlier.


By hilling up potatoes as they grow, this will help to increase your yield, protect the potatoes from blight spores and prevent damage from sunburn.

I hope that all goes well for you and that by the end of summer, we all have some great meals to look forward to, fries included!

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