How Deep do Potatoes Grow?


It’s mid-summer and the first potatoes are ready to dig. It’s a family activity to dig, sort, and wash the potatoes for storage.

Potatoes grow up to 12 inches deep. They usually grow no more than an inch or two deeper than they were planted and often form near the top of the soil, poking out as they swell. When you dig potatoes, you only have to go a foot down to get them all. Most will be 4-6 inches deep.

Digging and storing potatoes properly is very important. A harvest can be wrecked by digging wrong.  I’ll show you what I’ve learned that really helped me.

How Deep to Dig Potatoes?

If you just drop a True Potato Seed (actual seed) on the ground and it happens to sprout, the potatoes will only be an inch or two deep at best.  But that’s not how we plant them anymore, hasn’t been for 600 years.  Today, most potatoes are planted 6 inches deep and harvested at a similar depth.

Potatoes don’t really form much deeper than the seed potato was planted.  They really tend to form between the depth of initial planting and the top of the soil. Some tubers will even form completely above ground.  So, they don’t get deeper than where they were planted.

Now, a lot of potatoes are planted 6 inches deep and harvested at 12 inches deep.  that’s because they were hilled several times during the growing season.  Hilling potatoes is a very old technique to increase the harvest in a small area.

Basically, you plant potatoes, then burry them deeper as tubers become visible above ground.  often, they are 6 inches deeper after 3 times of hilling up the soil.  Some potato growers dig a 6-inch trench and plant them 6 inches deep in it. As they are hilled, the trench gets filled in.

If you trench, you need to dig deeply, and carefully to get your potatoes. It’s easier and you dig less if you hill, or mound up more than trenching.  I usually plant them in a trench around 6-inches deep. As they grow and tubers break the surface of the soil, I may shovel soil up higher on my rows.

It helps a lot to keep potatoes covered with dirt. Sunlight heats up exposed potatoes, stunting their growth. It also causes the potato to go green, which is mildly toxic and can make you sick. As soon as you see a potato bulging out above the soil, consider hoeing up a few inches of soil over the row.

Digging Potatoes without Damaging them

When digging potatoes, whether you use a fork or a shovel, some of them always get speared or sliced in half. Some people end up ruining a third of their harvest this way.  While damaged potatoes can be washed and used, they don’t store well even in the refrigerator. They have to be used right away.

Clearly marking rows and having soft, fluffy soil will greatly minimize damaged potatoes. I dug up 150-ish pounds of Red Norland potatoes today and damaged only six with my shovel. When the soil is loose, I can dig half of them with m hands.

Start digging a foot away from the first plant in a row and work your way closer. Sink the shovel deep and just loosen or lift the soil out. Don’t be aggressive, but take the largest scoops with your shovel or potato rake you can. When you find the depth of the potatoes, try to sink the shovle just beneath them.

As much as you can, dig outside of the potato zone and lift big scoops of soil. Most of the spuds will be easily visible and you can dig around for more with your hands. Once started, keep going down the row. I always go back and dig a bit wider, because I always find a few potatoes that I missed at first.

What to Dig Potatoes with?

Potato farmers use harvesting machines. Most gardeners people simply use a shovel. Then, there’s a potato fork that’s made specifically to dig up potatoes. I just use a shovel.  It works well, but I have to be careful.

A potato fork will dig up the tubers with minimal damage. It will dig deep and wide, and really limit the number of sliced or impaled potatoes. Now, a potato fork works best in loose soil.  Well I mean, everything works best in loose soil.

When Should I Dig up my Potatoes?

You can dig potatoes any time from a month after emergence to when the plants die in the fall. For the best harvest, wait until the plants die off as a sign that the potatoes are fully mature. Digging them early results in smaller, softer potatoes. The tubers get bigger and starchier as they grow. 

You can wait to dig them right up until a heavy freeze without seeing any damage to the harvest.  Potatoes will continue to grow bigger until the plant goes brown and dies back.  You can dig them at this point, or wait until you are good and ready. If you do wait, be sure to mark your rows.

The plants will disintegrate fairly quickly after they die back at the end of the season. Many gardeners have been embarrassed by not knowing just where their potatoes were planted.  If you haven’t hilled them, mark your rows with stakes, or some other marker so you don’t lose them.

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Jordan

I practice what I preach. Here in rural west Michigan, me, my wife, and 5 young kids work together to grow food, raise animals, and grow aninmal feed on just 1 acre. I teach homesteading classes locally, and help people where I can.

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