How can you tell your potatoes have gone bad – what are the signs?

Potatoes are popular in most households and can stay fresh for longer if properly stored. Most potato varieties can stay for a month but if stored at room temperature the potatoes stay about 2 weeks before you notice signs of potatoes gone bad.

I enjoy eating potatoes and making different recipes that add taste to my meals. This means that I always make sure I have a stockpile of potatoes in my pantry so that I don’t run out. But sometimes I find one of two that have gone bad. Although they can stay for a long time without going bad I don’t know what to look for to prevent them from going bad.

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How to choose fresh potatoes

fresh potatos

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Potatoes are low in calories, high in fiber and vitamin B6 and support cardiovascular health and fight cancer. If the potatoes you buy are very fresh they will last longer. The colour of the potatoes doesn’t matter when it comes to storage but the type of potato does. The skins of new potatoes are thin and smooth when fresh and they don’t contain any blemishes. Any kind of potato should be firm and don’t have any cuts or sprouts. It’s easier to inspect potatoes as you buy them instead of pre-packaged ones.

Potatoes gone bad

How to tell if potatoes have gone bad

Before potatoes begin to go bad, they undergo certain changes like sprouting or changing color. This means that their quality has started to degrade and the nutritional value has reduced which will eventually lead to potatoes gone bad. Here is what to look out for when that happens.

  1. Sprouted potatoes

This is an indication that potatoes have been stored for a long time at room temperature. On average, most potatoes begin to sprout after 1-4 months of harvesting. If the sprouted potatoes are still firm you can just remove the sprouts before you consume them and it’s best to consume them a week of sprouting as they will decline rapidly.

  1. Green potatoes

Green potatoes are an indication of toxicity and the green discoloration on the skin can lead to serious health problems. The green color occurs when the potatoes are exposed to light and chlorophyll begins to grow. Other varieties have a purple color. You can cut off the green part and enjoy the rest of the potato.

  1. Wrinkled or saggy potatoes

As potatoes age, they begin to shrivel up, get wrinkles, and begin to wither. Once this happens the taste of the potatoes changes and it’s time to discard them because they aren’t good to eat.

  1. Deep cracks

Potatoes with thumbnail cracks mean they underwent rough handling and storage. The cracks can contain mold or fungus that can cause the potatoes to spoil. However, small and shallow cracks that have healed indicate natural cracking during the growth process. You can ignore these cracks as they’re not a sign of potatoes gone bad.

  1. Mold

Potatoes can get mold if not stored properly. If the mold has only affected a small part of the potato, you can cut it off but if it has spread it’s best to discard the whole potato. Mold usually forms if there is exposure to moisture that’s why you don’t wash the potatoes before storage.

  1. Musty or soft potatoes

Old potatoes are no longer fresh and they won’t have that fresh earthy smell. This is an indication that the potatoes are spoiled. Some potatoes may look perfect on the outside but they’re rotting on the inside.

  1. Bitter tasting potatoes

If your potatoes

it means they contain a poisonous substance called solanine. You should discard such potatoes as they aren’t fit for consumption.

How to properly store potatoes

  • Fresh potatoes should be stored in a cool, dark, and dry place.
  • Avoid exposing the potatoes to light as light accelerates the production of solanine which makes the potatoes toxic with time.
  • Store your potatoes in an open container and a place that is well ventilated but don’t put them in plastic bags.
  • Refrigerating potatoes isn’t a good idea as the cold temperatures turn the start to sugars giving the potatoes a sweet taste and a darker colour.
  • With time your potatoes will develop eyes which are small sprouts that develop after harvesting. Get rid of them because they will spoil your potatoes.
  • Don’t store your potatoes next to onions or apples because they release gases that cause the potatoes to spoil.
  • Constantly check on your potatoes to remove the ones that are spoiled so that they don’t ruin the rest of the good ones.

Can you now tell when your potatoes have gone bad?

You can either boil, bake, roast or fry potatoes as part of your dish or by themselves. If you properly store potatoes they can last for about a month but they can easily spoil if not properly handled and stored. When potatoes go bad they have a very bad smell and they can affect the other good ones. Also look for those with deep cracks, mold, green spots or sprouts. Watch this for more on how to check bad potatoes.


Are grey potatoes safe to eat?

When you peel potatoes you expose them to air which makes them turn grey or brown. This is a harmless natural reaction which doesn’t compromise the quality of the potatoes and you can safely cook and eat them.

Is it safe to eat potatoes with black spots?

These are called internal black spots and are as a result of bruising when the potatoes are lying against each other for a long period of time. The potatoes are safe to eat you just need to cut out the spots.

Do potatoes become poisonous?

Green potatoes and sprouts are poisonous to eat. Throw away green potatoes and cut out sprouts before eating the potatoes.

Can undercooked potatoes make you sick?

Potatoes can absorb E. Coli or Salmonella found in the water and soil while growing or during harvesting. Cooking potatoes helps to destroy these bacteria which can cause you diarrhea, upset stomach, abdominal cramps or fever.

Do cooked potatoes go bad?

This depends mostly on how the potatoes are stored. All cooked potatoes should be refrigerated within 2 hours of cooking and if properly stored they can last 3-5 days in the fridge.


A diet guru by day and an avid reader by night, Tim is a nutritionist based in the beautiful city of Ottawa, Canada. He loves everything to do with health and believes going the natural and organic way is a necessity. When not busy disapproving of people’s diet choices, you can find him taking online classes for this and that while waiting for his cheat day. Tim also loves white sandy beaches, swimming (anything aquatic, really), long drives to the countryside, and travels to new cities and states. He also loves DIY projects and checking out new restaurants with his girlfriend.

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