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There’s nothing worse than going to gather potatoes from storage only to find that most of them have rotted! Potatoes are supposed to have a pretty long shelf life so how could seemingly healthy potatoes all have gone bad in storage?
The reason potatoes start to rot in storage is that diseases enter potatoes through injuries to the skin. Heavy moisture and high temperatures also help rot spread more quickly.
It can be discouraging to see all your hard work go to waste from disease. But, there are several preventative measures you can take to ensure that your potatoes last for months in storage. I’ll also share what varieties I think are best for storing.
What causes potatoes to rot?
Potatoes start to rot primarily due to disease brought on by damage during harvesting and improper storage methods. You’ve probably introduced diseases into your storage potatoes without even realizing it.
When harvesting potatoes, it’s very easy to knick their skin or to accidentally pierce them with your digging tool. If you plan to eat your potatoes right away, these blemishes aren’t that big of a deal. But for long-term storage, they can be detrimental.
These wounds have now opened your potatoes up to a whole host of diseases found in the soil which can then spread to the rest of your potatoes. Luckily, we have another great article all about how to grow no-dig potatoes which can help prevent these injuries.
Another way that rot can quickly overtake your storage potatoes is from poor storage conditions. A storage area that is too humid and too hot is the quickest way for rot to develop.
Higher storage temperatures create the perfect environment for disease-spreading bacteria. Too much moisture and mold may start to show up on your potatoes as well.
Common potato diseases
Common potato diseases include Fusarium dry rot, wet rot, and pink rot. All of which can be detrimental to your potato harvest. Here’s what you need to know about each disease.
Fusarium dry rot
This type of rot is known as dry rot because the site of the disease generally remains dry despite the rot. Dry rot is a disease that is present in the soil and makes its way into the potato through wounds in the skin.
When you cut into a potato with dry rot, you’ll notice black or dark brown discoloration on the inside. The outside of the potato may also be shriveled up and dry, hence the name.
Soft rot is easy to detect because it starts on the surface of the potato before rotting the inside. If you notice any soft, wet, and brown spots on the outside of your potatoes, they should be discarded immediately as this is likely to be soft rot.
Curing potatoes can be one of the best ways to prevent soft rot from taking over your potato harvest. I’ll talk more about how to cure potatoes later on.
Pink rot can be tricky because it’s one you might not notice right away. The outside of your potato may look perfectly fine despite being infected with pink rot. It might feel a bit soft or rubbery on the outside but this might be something you quickly glance over.
Yet, when you cut into a potato with pink rot, you quickly learn how this disease got its name. Within minutes of being exposed to air, the inside of the potato will start to turn a pink color.
So, how can you tell if your potatoes have pink rot without cutting into every single one of them? Well, you’ll have to be a bit more proactive to manage pink rot. Pay attention to what the plants looked like during harvesting.
Are the leaves wilting near the base of the plant? This may be a sign of pink rot. The best way to prevent the spreading of pink rot in storage is to make sure the potatoes are dry. Any wetness or saturation is a surefire way to spread the disease.
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How to prevent potato rot in storage
The first step in preventing potato rot is to make sure you pick a good storage location. Many people choose to store potatoes in their cellars or basements. This is definitely a good option but not everyone has a basement.
The next best place would be in a garage but only if it’s unheated. Remember, storage potatoes shouldn’t get too warm!
If you also don’t have a garage, then a cabinet that stays cool and dry most of the time is your best bet. Try not to place them next to any kitchen appliance that may cause them to get too warm. Near ovens and refrigerators is not an ideal location.
If all of your storage locations seem to be a little too humid for potato storage, you can try setting up fans to keep the air moving. Dehumidifiers are also a great option if you can get your hands on one.
Something else that might seem counterintuitive but is crucial to preserving your potatoes long term is to NOT wash them before putting them into storage. Throwing a bunch of wet potatoes into storage together is the perfect environment for rot to spread.
If they seem exceptionally dirty, let them dry a bit and then brush the dirt off with your hands. Then, you can wash them as you use them over time.
Make sure not to store them too close together. Having them spread out far enough can give you a little bit of a buffer to save your potatoes if rot does start to develop. Packed too closely and disease can spread like wildfire.
I wouldn’t pack them any deeper than three layers of potatoes in whatever storage container you’re using. Some good storage container options are mesh bags, paper bags, or cardboard boxes. Try not to store them in plastic bags as these can lock in moisture that you don’t want on your potatoes.
If you find you’ve damaged some of your potatoes in the harvesting process and don’t think you’ll be able to eat them anytime soon, then consider composting them or giving them away to someone that can use them.
Also, if you pull a potato out of storage and notice a small rot spot when you cut it open, you can still eat the rest of the potato. Just cut the rotted part off and discard it. No need to waste a perfectly good potato!
How to cure potatoes
Curing potatoes is the process of storing them in a warmer location for several days before moving them into storage. This way the skin dries out and helps to prevent diseases from entering the potato. It also just preserves their longevity overall.
The easiest way to cure potatoes is to wait for the above-ground part of the plant, or the greens, to die back. Then, you can leave them in the ground for another week or two. After that, they should be properly cured and ready for storage.
Potatoes aren’t the only vegetable that benefits from curing. Onions, winter squash, and sweet potatoes should also be cured before being put into storage.
How long should potatoes last in storage?
When stored properly, potatoes should last between 4 to 5 months. Of course, if you’re anything like me potatoes don’t last any longer than 2 months simply because I eat them!
Remember to check on your potatoes often for any signs of rot or disease. If you catch it early enough, you can remove the diseased potatoes and keep them from spreading anything to the rest of your potato harvest.
Best potato varieties for storage
Red potatoes tend to have thinner skin and therefore are much more likely to incur damages during the harvesting process. This makes them less than ideal for storage.
The best potatoes to use in storage are white or yellow potatoes. Here are some of the varieties that I like the best.
So now you know everything there is to know about why your potatoes are rotting in storage and what you can do to prevent it. Just remember to try and keep your potatoes in a cool and dry storage area and to immediately discard any potatoes showing signs of rot.
Don’t be afraid to play around with different storage methods and locations until you find one that is the most ideal for your potatoes. Basement too moist? Try a closet or pantry. Not enough pantry space? Try a garage. You have lots of storage options to choose from.
If the rot patch is small, you can also just cut that part off and then consume the potato as normal. This way, you can enjoy garden-grown potatoes and cut back on your food waste in the process.
Johnny’s Selected Seeds. “Potatoes” (2022) https://www.johnnyseeds.com/vegetables/potatoes/
Check out these must-have gardening products
You don’t need much to start gardening, but some tools and products will make a difference in how comfortable and effective gardening can be for you. Here are my favorites:
- Garden Trowel. A good garden trowel will last you many years. I love how sturdy this hand trowel from WOLF-Garten is, the metal doesn’t bend and it has a nice grip.
- Trimming Scissors. I use them for delicate pruning and harvesting all summer long, and they’re super handy. These Teflon Trimming Scissors are extra nice because they don’t rust as easily.
- Dutch Hoe. Dutch hoes may seem old-fashioned, but there’s nothing like a quick sweep through the topsoil to get rid of small weeds – no bending required. I love WOLF-Garten’s selection: this dutch hoe coupled with their universal handle.
- Grow Lights. These grow lights from Mars Hydro are super strong, yet dimmable, so they fit every stage of growth. They don’t put out too much heat and are very economical.
- Seedling Trays. There’s an art to choosing the best size for seedling trays so that it holds the perfect amount of water and gives the roots enough room to grow. These germination plugs are perfect when coupled with 1020 bottom trays.
- Liquid Fertilizer. You’ll need to feed your plants from the seedling stage, all the way to fruiting. This organic fish & seaweed blend is a very versatile option. Use it half-strength for young plants and full-strength for established plants.
Browse our list of tools, fertilizers & pesticides, indoor growing products and seed shop recommendations – we hope you find our selection useful and it saves you some time!