Cutting seed potatoes into smaller pieces before planting them is a common practice that provides gardeners with more plants per potato. Although this technique is popular, there are a few drawbacks that may be concerning to those beginning their potato-planting journey. When seed potatoes are cut, they are more susceptible to disease and mold growth. This is because the inside surface of the potato is moist, which is the perfect environment for mold to flourish. Luckily, an easy-to-make hydrogen peroxide spray can kill mold even after it has grown on the cut potatoes surface.
YouTube personality Gary Pilarchik of The Rusted Garden shared a video tutorial on using this spray to treat your moldy potato halves. To make this spray, all you will need is 3% hydrogen peroxide, water, and a spray bottle. Spray the potato in the areas where you notice mold growth. Apply enough to drench the mold. You will notice the hydrogen peroxide solution begins to fizz after it comes into contact with the mold. “Its going to kill off all the mold and all the fungus,” Pilarchik explains. Clean off the residue and allow your potatoes to dry, and they should be restored.
As a potato grower, you’ve probably encountered moldy potatoes when sorting through your harvest The fuzzy white or gray mold that grows on stored tubers is common but concerning A natural question is can I plant moldy potatoes or are they unsafe to use as seed?
In this comprehensive guide, we’ll cover everything you need to know about planting moldy seed potatoes. You’ll learn:
- Why potatoes get moldy in storage
- The main types of potato mold
- Safety tips for planting moldy tubers
- How to identify healthy seed potatoes
- Proper potato storage to prevent mold
What Causes Potatoes to Get Moldy?
Several factors can lead to mold growth on stored potato tubers:
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Excess moisture – Wet potatoes allow mold spores to thrive. Always cure and store potatoes in a dark, cool, dry place.
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Bruising or wounds – Cuts and cracks give mold an entry point Handle potatoes gently to avoid this
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Long storage times – Over 5-6 months, potatoes’ natural antifungal compounds decline.
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Poor ventilation – Still stagnant air encourages mold. Ensure good airflow in storage.
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Warm temperatures – Ideal potato storage temperature is 38-40°F. Heat promotes mold.
Common Potato Mold Types
There are various mold species that can grow on tubers:
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Gray mold – Forms fuzzy gray/brown spots. Spreads rapidly in warmth and humidity.
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Black mold – Causes black velvety dots on skins. Produces harmful toxins.
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Blue mold – Leads to light blue surface fuzz. Largely cosmetic.
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White mold – Thick white growth on tubers. Spreads quickly on stored potatoes.
Is It Safe to Plant Moldy Potatoes?
Whether it’s safe to plant moldy potatoes depends on the mold type and extent:
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Potatoes with surface mold only can often still be planted. Gently brush off mold. Avoid deep penetration.
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Black mold is unsafe. It produces toxins that can spread disease. Avoid planting.
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Inspect seed potatoes individually. Discard those with concerning mold.
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Cut out minor mold and plant the rest of the tuber.
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Consider treating cut seed with a fungicide to prevent spread.
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If mold has been an issue, grow resistant varieties like Yukon Gold.
Signs of Healthy Seed Potatoes
Look for seed potatoes that are:
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Firm, with no soft spots or hollows
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Free of dark mold or rotting
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Intact, with minimal cracks or wounds
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Reasonably smooth, with few eyes/sprouts
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Not shriveled or wrinkled heavily
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Sprouting uniformly after planting
Storing Potatoes to Prevent Mold
Proper post-harvest storage prevents moldy potatoes:
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Cure fresh potatoes 1-2 weeks in warm, humid conditions.
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Store cured potatoes in complete darkness. Light causes greening.
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Maintain storage temperature around 40°F. Avoid freezing.
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Keep potatoes damp but not wet. Allow good airflow.
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Periodically check for mold or rot. Remove affected tubers immediately.
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Eat or plant within 5-6 months before quality declines.
Following best harvesting and storage practices reduces the likelihood of mold.
What If My Whole Crop Has Mold?
If all your potatoes have mold, discard the entire harvest. Purchase certified disease-free tubers to use as seed for next season.
Thoroughly sterilize any containers, tools, or areas that held the moldy potatoes to destroy spores. Rotate planting locations to prevent disease carryover.
Consider preventive measures for future crops:
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Improve crop rotation. Avoid repeat planting in same soil.
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Space and prune plants for good air circulation.
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Treat seed pieces with antifungal agents like neem oil.
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Select mold-resistant potato varieties.
Finding moldy potatoes in storage is common but preventable with proper harvesting and conditions. Moldy seed potatoes can often still be planted safely if mold is superficial. However, discard any with black mold due to disease risks. With vigilance and preventive care, you can minimize potato mold issues and enjoy a healthy homegrown crop.
Protect your potatoes by following these tips
In the YouTube video shared by Gary Pilarchik of The Rusted Garden, you will notice that it is recommended to mix your 3% hydrogen peroxide with water if you are concerned about the solution being too strong. You may use a mixture made up of half hydrogen peroxide and half water instead. The 3% hydrogen peroxide solution can be found and most drug stores and supermarkets. If you prefer to shop online, you can also pick it up on Amazon for about $7. Amazon is also a great place to snag an extra spray bottle if you do not already have one.
Once you have gathered all of your materials, it should be pretty simple to assemble your solution to spray onto your potatoes. “That will give your potatoes a better chance of surviving once they get into the ground,” Pilarchik says.
You may be wondering whether it is possible to prevent mold from growing on your potatoes after you cut them in the first place. Fear not, there are a few precautions you can take to minimize the need to spray your potatoes down with this solution. First, do not store your cut potatoes for long periods before planting them. Cut them only about a day or two before planting them to minimize the likelihood of mold growth. You may also choose to apply powdered sulfur to protect them.
Save Potatoes, Bulbs, and Rhizomes that Show Signs of Mold & Fungus with a Hydrogen Peroxide Spray
FAQ
Can you plant potatoes if they are moldy?
Expert Response
Hi- if you have time and space and are curious, you could slice of the moldy tissue and plant them today or tomorrow. It’s likely that plant growth and yield will be reduced- by how much we can’t say.
What to do with moldy potatoes?
Yes, you can cut mold off potatoes. If a potato has small spots of mold, you can cut away the affected areas. However, if the potato is extensively moldy or has a soft, rotten texture, it’s best to discard it. Mold can penetrate deeper into the potato, so cutting away the visible mold may not remove all of it.
Can I plant rotting potatoes?
Don’t plant sprouted potatoes that are: Rotten. Moldy. Overly mushy (beyond just shriveled or soft)
Are potatoes still good if they have mold?
Mold may appear as fuzz or a few dark spots that are brown, black, red, white, or bluish gray. Potatoes sometimes cause food poisoning. To avoid getting sick, be sure to eat cooked potatoes within 4 days and immediately throw away any potatoes that show signs of mold.