How to Tell If a Potato is Bad? +All Causes & Fixes!

how to tell if a potato is bad

Did you find some potatoes with wrinkly marks and alien growth in your garden? Thinking to throw them out? Not yet buddy! First you need to know if they are really bad enough.

But how to tell if the potatoes have gone bad?

You can identify rotten potatoes in your garden by spotting powdery and murky bumps, look like warts and black spots. Fungus and wet soil could cause black spot formation and reddish tissue deterioration. Moreover, Green parts of potato tubers are toxic.

These are only just the teaser! We have prepared a detailed article with preventive measures and correct storage options. Interesting right?

So, don’t wait and have a look!

What Do Potatoes Look Like When Growing?

Potatoes grow under the soil and their looks can not be seen. But, the plants of them change with time and indicate the growth of the potatoes. If you are growing potatoes for the first time, you may fail to catch when the potatoes are growing day by day.

When the potatoes growth are developing, their plants looks will change to:

• Flowers in the plants – Tiny potatoes

• Flowers dying – Medium potatoes

• Leaves or plants dying – Matured potatoes

Let me take you to the trifles of their appearances.

1. Flowers in the Plants – Tiny Potatoes

When the potatoes are in their early age and their size is tiny, the plants will have flowers. The leaves tend to remain in a fresh and green vibe.

2. Flowers Dying – Medium Potatoes

As the potatoes start growing to a medium size, the flowers start dying. Along with it, the leaves and the plants turn into a light yellow color.

3. Leaves or Plants Dying – Matured Potatoes

For matured or ready to eat potatoes, you have to wait till the plants or their leaves die. Before dying, their color changes entirely to yellow. These potatoes are also ideal for harvesting.

8 Universal Ways to Tell If a Potato is Bad in 2023

signs of a bad potato

None of us would like to eat a bad potato even if you are an avid potato lover. You may feel the strange awful taste if you consume it without knowing the condition. Only, learning the signs will lead in this regard.

Thus, you will easily know which ones are the real rotten and which are just exceptions. There are common symptoms that most of the gardeners follow.

How about knowing them?    

1. Strange Smell

Strange smell coming from raw potatoes after cutting them is indicating bad potatoes. The smell will be bitter, rotten and moldy. You can not smell it strongly without cutting them.

That’s why you need to cut them and smell the scent. If one part is stinky, throw it away. You can eat the part, which is still smelling earthy. Do not eat the potato in case each part is spreading a strange smell.             

2. Mold

Mold is a greater issue that occurs from storing mistakes. If the potatoes are placed in a space with lower temperature and higher humidity, mold grows in their body. 

If the mold is still small and fewer, you can cut that portion and discard it. Never eat the potatoes with several moldy indications.      

3. Spots On the Body

Spots like dark and wrinkles are common in the case of bad potatoes. If your potatoes are a bit older, they may face the problem. With time, they began to grow these and became mushy types.

In this regard, we recommend not consuming the potatoes as they can harm your health conditions. Place them in the bin as they can spoil the other potatoes.            

4. Soft and Tender

Too many soft and tender potatoes are regarded as rotten or becoming bad gradually. You can confirm by smelling them and looking for dark spots on their surface. Do not eat them if you find such issues.        

Potatoes can be soft and tender even when they are fresh and edible. At that time, they carry no strange smell or spots on the body and you can have them without any worries.      

5. Green Spots

Organic and chemical-free potatoes tend to become greenish colored. This can also happen if they get sunlight regularly.

That green portion is not edible as it carries solanine, which is toxic. So, never use the green portions in cooking or other ways of consuming potatoes.   

6. Shoots and Sprouts

Shoots and sprouts occur in the potatoes which are free from chemicals and tend to grow more. As they are already harvested, they grow small shoots and sprouts in their body.

Moreover, higher humidity can be a plus point for producing these. You can have these potatoes if they have no bad smell or wrinkles. Just cut off the shoots and sprouts and the potatoes are ready to use.             

7. Parted Liquid  

Almost all of us know that smashed potatoes carry a bit of liquid on their top. No wonder, we mix it again with the potatoes.

But, when the liquid tends to separate from the smashed potatoes, your potatoes become bad. In most cases, the liquid contains a stink and white haze. Throw the potatoes before anyone eats them.

8. Mold with Stink

It happens in cooked potatoes and appears with mold and stinky smell. Experts say it occurs because of bacteria and bad potatoes.

If you encounter such a dish, never eat it. We recommend eating potato dishes for up to 4 days and discarding them the next day.         

5 Signs that Your Garden Potatoes Have Gone Bad

identify garden bad potatoes

The initial signs of your garden potatoes going bad are the appearances. But sometimes good potatoes can appear bad because of wrinkles and spots. That’s why identifying the problem in them is important.

We’ve created a collection of telltale signs that indicate rotten potatoes. Let’s have a look!

1. Powdery Spotty Scabs

Watch out for murky bumps that look like warts on the potato tubers. Later, this breaks and spews out dark spores. Powdery scab can easily spread in gardens season to season due to buried root or potato peels.

However, if you notice raised blisters on brown tubers, you can be certain that a fungus is to blame.


You should steer clear of planting potatoes in soils that have poor drainage. Don’t plant tubers that have any of the above problems. If you get a disease, don’t plant tomatoes for at least five years and take potatoes out of the rotation.

2. Green Tubers

Sometimes while digging or when potatoes get bigger, the young tubers are left out in the sun. Next, the sun triggers the formation of chlorophyll green stripes on the potato. Green parts of potato tubers are toxic and should not be consumed.


Make sure that any tubers that are sprouting are buried in the compost. The darkest environment possible should be used to store potatoes.

3. Center Hollow Cavities

Far too excessive water or agrochemicals can cause potatoes to grow too quickly, resulting in a condition known as “hollow heart.” Chalky decay and fungus can line a chamber and cause discoloration. Remove any unappealing brown spots before use.


Fertilize the plants when they are young, right around the time that roots are beginning to form. You should steer clear of planting hollow heart variants such as Chippewa, Mohawk, and Russet potatoes.

4. Small Black Spots and Scruff

Look for misshapen, withered lesions on your potato tubers. Microbial fruiting bodies, typically black and flat, should also be  visible on the surface of the tubers. This is caused by fungus in cool, wet soil.


Lowering the amount of inoculum in the compost and in the potatoes is the only way to get rid of it. Fungicide can be applied to seed fragments or ground. As an additional precaution, shallow seeding is recommended in cold soil types.

5. Reddish Tissue Infection

Occasionally, the outer surfaces of potatoes exhibit gray to reddish brown abnormalities with a waterlogged texture near lacerations.  People usually call this a leak caused by oomycetes in the compost. When the potatoes are picked, any cuts or bruises let the fungus in.


To stop this disease, don’t hurt the tubers when you harvest them, particularly when it’s warm and muggy. Harvesting tubers too early can result in damaged tubers because the periderm is not fully developed. If this condition is found in storage, keep stems at 45°F.

4 Signs that Your Stored Potatoes Have Gone Bad

identify stored bad potatoes

Perhaps you have unearthed some gooey moldy lumps of potatoes in your pantry. Even though the moldy mass is one that we would not hesitate to discard, what about the others?

Here is a compiled list of identifiers for potatoes that are rotten. These will definitely help you out!

Go through them.

1. Excessive Dryness

Your potatoes may appear to have areas that have scuttled and frequently withered while they are being stored. Slashed tubers reveal brown, disintegrated tissues with white, reddish, or yellow overgrowth.

White fungal mycelial growth develops on the tubers’ surface during storage, leading to profound, dry rot below. Microbes get into the potatoes when they are cut while they are being picked or when they have soil wedged to their skin.

2. Blotchy and Uneven Colors

Occasionally, you will observe pale, hard, dotted spots on the potato. Additionally, the tissue just beneath the surface is both tough and mottled dark brown. This is late blight, which initially manifests in storage and makes the tubers become lead-colored.

Black spots, on the other hand, may be visible just beneath the potato peel. The intrinsic signs may be linked to the flatness or other signs of bruising on the tuber skin.

3. Silvery Coating

Some contaminated tubers that were stashed in extreme heat for a long time get a delicate layer of deep green to black spores that can be seen with the unaided eye.  After washing, the outer layer of the tuber will have a silvery sheen patch.

While the spread of infection is inevitable in storage, it is manageable if temperatures are kept low enough. The ideal temperature for a storage unit is 40 degrees Fahrenheit, but it should have air conditioning and ventilation fans.

4. Center Turns Black

Occasionally, a potato may appear clean and fresh, but emit an unpleasant odor. These potatoes have flaws on the inside that aren’t visible until after they are peeled and sliced open.

In the event that an injury occurs during harvesting, the lack of oxygen that occurs during storage will cause the tissue to deteriorate and turn black from within.

It is not possible to reverse the condition. But, if you catch it in time and make the necessary adjustments to the way the crop is stored, you can keep it from affecting the entire harvest.

5 Effective Process of Storing Potatoes

In case of storing potatoes, we make the significant mistake. It happens due to our lack of proper knowledge regarding the storing manners. As a result, the potatoes become bad and we have to throw them away in the bin.

So, we researched thoroughly, and found some effective methods to store the potatoes safely for a longer duration. Well, we won’t prolong more as we know how much desperate you are know these.

Let’s get to the points asap.                  

1. Countertop / Cupboard  

This system is pretty popular among the houses with less space. First, get an aerated bag and keep the potatoes in it. Then, place it in a countertop or a cupboard.

Ensure proper air circulation and keep onions away from potatoes. In this way, they will remain fresh for two to three weeks.      

2. Fridge

Experts suggest keeping potatoes in the fridge is not always good. But, if you have no other choice, you can try this out. You can keep both raw and cooked potatoes in the refrigerator.

In the case of raw potatoes, do not wrap them in a plastic bag. Again, cooked potatoes should be stored in an airtight box or container.      

3. Pantry

Pantry is regarded as a safe place for storing the potatoes. In a pantry, both air circulation and temperature remain balanced, which is sufficient for potatoes.

Though sprouts can grow after two weeks, potatoes stay fresh for up to three weeks.           

4. Canning

Canning is an effective way for storing potatoes for a longer duration. In this way, they can be stored for up to 5 years. Even though we were shocked to learn this, it is true, friend.

But, the process needs to be done perfectly. First, cut your potatoes to set them in a jar. Then, mix lemon juice, salt and water into the jar. Then, complete the task properly.      

5. Basement 

Your basement is a great spot for storing potatoes for up to 2 months and more. You just have to ensure a balanced air circulation in the basement.

Storing them there is much easier. All you have to do is place the potatoes in a paper bag or cardboard box and loosen the cover. Never use a plastic bag as it can make them rotten soon.         

How Long Can Potatoes Last?

Longevity is a hallmark of potatoes. But there are some things that can affect how long they survive.

Potatoes can stay in the ground for up to a month before being picked. Keep in mind that potatoes are responsive to changes in moisture content.

Your garden potatoes will grow to their full potential when soil moisture remains stable. It is best to avoid working in water-saturated soil because it can lead to improperly formed potato and rot.

Keep potatoes in the kitchen storeroom and away from sources of moisture. Only then you can anticipate that they will remain edible for a number of months.

Moreover, store them in a room that has adequate ventilation. The potatoes can be stored for several years if properly frozen.

Is Eating a Bad Potato Riskier to Health?

Yes, eating a bad potato is riskier to health. You may suffer from food poisoning to other severe illness. Not only bad potatoes, eating cooked potatoes after 4 to 5 days is also dangerous to health.

It is because there grows bacteria in the potatoes and in some cases pathogens also. These are highly efficient in encouraging food poisoning like listeria and staphylococcal illness.

 Moreover, you can feel stomach aching and fever at first. Then, the situation gets worsen by vomiting, muscles aching and headache. Diarrhea is also a consequence of eating bad potatoes.

The worst is getting admitted in hospital and the rest is unknown. The treatment may help you getting well in a few days to weeks. Therefore, never eat the potatoes after detecting they are bad.                                  

Before Harvesting, How Long Can Potatoes be Left in the Soil?

Answer: After the crops die, it is recommended that the potatoes be left in the soil surface for 2 – 3 weeks. The potato skin will harden and cure over time, making the potato more robust for storage.

When is the Ideal Time to Prune the Tops off of My Potato Plants?

Answer: Potato plants can have their tops trimmed when the tubers are harvestable. Trimming the tops of the potato plants before all this time will prevent them from producing enough food for themselves.

Why Should You Keep Potatoes Away from Onions?  

Answer: You should keep potatoes away from onions to reduce shoots and sprouts. It is because onions will let the potatoes to be affected by ethylene gas, which encourages shoots and sprouts.           

How Long Do Sliced Potatoes Remain Fresh in the Fridge?  

Answer: Sliced potatoes will remain fresh in the fridge for up to 24 hours. But, it requires a proper way to maintain. You have to take cold water and place the slices in the water. Then, keep them in the fridge.     

How Long Can You Store White Potatoes?

Answer: You can store white potatoes for 3 to 5 weeks in the pantry. It is because the humidity of the pantry is suitable for white potatoes to remain fresh and edible.       

Final Thoughts

Now you know how to tell if a potato is bad or not. If you find any one of the listed faults, whether in field or storage, you shouldn’t wait. Just throw them out.

Follow us for more gardening hacks. And don’t forget to share your experience.

We wish you the best of luck with your future gardening endeavors! See ya!

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Mary Burton

Hey! I am Mary Burton. I’m a mother of two kids and a Horticultural Science graduate from the University of Florida. Living my life with my loving kids and husband, I always learn new and amazing things. Plus, by doing my dream works of farming and gardening I feel alive. I will not say I am an expert, but yes, I am learning for nearly 5 years and I know my job. Sharing the knowledge and my daily farming and home decor projects would surely make people's life easier. Thus, this brings me here, in front of you guys. Really excited about doing this.

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