When you cut potatoes and brown spots appear, it's easy to cut them off, but where do they come from? Many different factors can cause brown spots to appear on the inside of potatoes.
What is potato rust?
Internal rust spots are small brown spots that appear on the inner flesh of potatoes. Usually more numerous and dark or slightly reddish-brown in color. They may appear in clusters or scattered throughout the potatoes.
These spots can be caused by poor soil and are most likely to form if the potatoes are deficient in potassium and lime. Some types of potatoes are more resistant to rust than others, but any type of potato can develop rust if conditions are harsh enough.
Can stress cause brown spots?
Brown spots are more likely to appear in the pulp if the plant is under a lot of stress while forming the tuber. In most cases, these spots are small, but severe stress may cause larger spots to form.
Stress is often caused by unsuitable growing conditions, so if you are growing potatoes at home, make sure you provide them with everything they need.
If you want to grow healthy potatoes and minimize your chances of encountering brown spots, consider using a high-quality soil tester to measure the nutrient levels in your soil. It will allow you to optimize growing conditions and ensure your potatoes get the necessary nutrients.
It is also important to rotate crops every year to reduce the risk of soil depletion.
What is potato virus?
In some cases, brown spots can be caused by a viral or fungal infection. There are a lot of them — which may have you worried about whether potato chips are safe to eat or if they can make you sick.
Fortunately, these viral and fungal infections are harmless to humans, and eating them won't harm you. They are endemic to potatoes and only attack the flesh of the tuber. They should also not spread to other crops outside of the family Dioscoreaceae.
What are the effects of uneven watering?
Uneven watering can also cause brown spots on potatoes, or it can be difficult to maintain if the summer is particularly hot.
Often, waterlogged or overwatered potato plants will cause the tuber to develop something called a hollow. This is a notch in the flesh of the potato fruit in the middle, sometimes with a brown ring around it.
This usually occurs when the plant is under water, causing slow growth, and then watered heavily, causing a sudden acceleration in growth.
Due to the sudden growth, the tuber splits internally, leaving a hole in the center. As the potatoes continue to develop, these cracks may develop brown edges.
Some large potatoes may even develop multiple such holes, although most potatoes will only have one. Consistent watering helps reduce the risk of hollows forming.
Can pests cause brown spots?
There is also an insect called the potato psyllid that causes browning of potatoes. This insect damages the plant rather than directly affecting the potato; it is a sap-sucking plant that eats the plant tissue.
The insect carries a bacteria that also affects the plant, causing stress that turns the inside of the potatoes brown.
Of course, other insects that burrow into potatoes can also cause brown spots, but they leave holes in the skin, so in these cases you should be able to pinpoint insect damage.
Are potatoes with brown spots safe to eat?
Since there can be a variety of causes behind brown spots, you may be wondering how to tell if your potato chips are safe to eat—because it's often impossible to figure out which of the above causes is causing the brown spots.
Fortunately, nearly all of these potential causes of damage do not make the rest of the potato meat dangerous to cook and eat. They are all fairly harmless, including viruses.
You can use a sharp knife to cut away the brown color from the potatoes. Cut off any particularly speckled areas and discard them, and use only the clean white parts of the potatoes.
Pay attention and observe:
- Do the potatoes taste good?
- Is the flesh around the brown area mushy or slimy?
- How far did the brown area spread through the potatoes?
- How old is Potato?
If you're unsure, it's best not to eat brown potatoes as they may make you sick. A few brown spots are almost always good, but be wary if the potatoes are old, full of brown spots, or have a strange smell when cut.
A range of different factors can cause brown spots to appear on the inside of potatoes, and it's normal to encounter small brown spots when preparing these vegetables, especially if you grow your own potatoes.
To prevent brown spots on potatoes, store them in a cool, dry, dark place, such as a pantry or cellar. It's also important to handle potatoes gently and avoid bruising them, as this can become an entry point for bacteria and fungi.f