It is common to cut seed potatoes before planting them. This will save seeds and help your garden grow more plants.
As the weather starts to warm a bit in the spring it’s time to plant your seed potatoes. No matter what garden zone you live in, you should plant potatoes without any frost protection about two weeks before the last frost date in your area. (To learn what garden zone you live in check out this post).
Cutting seed potatoes is a pretty common practice for many gardeners. But cutting seed potatoes before planting comes with a few drawbacks along with its many advantages.
Just watch the video above, which is part of my 5 minute Friday video series, to get a quick answer to your questions about how to cut seed potatoes. If you want more details on cutting seed potatoes then read on!!.
If you look at a seed potato you will see that each potato contains many “eye’s”. The small dimples you see on the surface of a potato are the eyes. As a seed potato gets ready to plant it will start to “chit” or sprout from those eyes. Those sprouts are what will eventually become the potato plant. And really each plant only needs 3 or 4 of those sprouts to establish and be productive.
So a bigger seed potato like the one in the picture above might have 15 or more sprouts. This seed potato can be cut into two or three pieces, with the sprouts split between each one. Each of the pieces will then sprout, grow and become its own potato plant.
It is important to know how to cut your seed potatoes. When cutting seed potatoes I like to try and keep the pieces big and chunky. Also, I like to make sure that after cutting, each piece still has at least four eyes on it. So most often I only cut the seed potato into 2 pieces. A particularly large seed potato may get cut into 3 pieces. Some people will say this isn’t true and that the seed potato can be cut into much smaller pieces with only two eyes. I think chunky pieces with at least 4 eyes give the potato plant the best chance of getting strong.
With a sharp knife, cut off a big chunk of your seed potatoes along a line that gives each piece at least four eyes. Be careful not to cut through any of the eyes, as this will kill the sprout. That’s it; one seed potato turns into two or three, so less seed can grow more potato plants. When I cut up a seed potato, I like to have a piece that is at least 2 or 3 inches long and wide.
Potatoes, tomatoes, peppers, and other plants in the Solanaceae family can get soil-borne viral or bacterial diseases. If you live in an area with these diseases, Then you might want to reconsider cutting your seed potatoes. Many garden experts recommend against cutting seed potatoes if you have these types of diseases in your garden. It is thought that cutting your seed potatoes makes them more likely to get problems from the soil.
Cutting the seeds has never given me any problems with potato diseases. But there is that possibility. Because of this, if you have had potato diseases in the past, don’t cut your seed potatoes. Additionally, keep your garden clean. If you see any sick plants in your garden, remove them and throw them away. Do not put them in your compost bin. Practicing good crop rotation will also help keep disease problems down in your backyard garden.
As a homesteader and gardener, I know that potatoes are one of the most versatile and nutrient-dense crops you can grow. They store well, taste great, and can be prepared in dozens of ways. But before you get to eat those delicious homegrown potatoes, you first have to grow them – and that starts with high quality seed potatoes.
One of the keys to getting your potato crop off to a strong start is knowing how to properly cut, cure, and store your seed potatoes. Cutting seeds tubers stresses the potatoes, increasing the chances of disease and rot setting in. So you need to handle cut seed potatoes carefully to preserve their viability. Just how long will cut seed tubers last before planting? What’s the best way to store them to maximize shelf life? In this article, I’ll share everything I’ve learned over the years about how long cut seed potatoes will last.
Why Cut Seed Potatoes in the First Place?
Before we get into proper storage and handling, let’s review why we cut seed potatoes rather than planting the whole tuber Cutting seed tubers into smaller pieces allows you to get more “seedlings” from each potato More plants per seed potato equals more yield potential! Cutting also creates more evenly sized seed pieces, helping ensure uniform sprouting and growth.
Whole small tubers (1,5-3 oz) can be planted without cutting But larger tubers need to be cut into blocky chunks roughly 15-2 ounces each, Each chunk should have at least 1-2 eyes to sprout, Professional potato cutters aim for 70% of seed pieces between 1,5-3 oz, The average is around 1,75 oz per piece,
Curing Newly Cut Seed Pieces
Once cut, seed potato pieces need time to heal and “cure” before planting. This curing period allows the cut surface area to develop a protective barrier and avoid rotting Proper curing also helps overcome dormancy and promote vigorous, even sprouting.
Ideally, freshly cut seed potatoes should cure for 1-2 weeks before planting. The exact curing time depends on the potato variety, their physiological age, and whether they’ve already started sprouting. Young seed potatoes cure faster than old seed.
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Seed that’s sprouted needs less curing time, only 5-7 days.
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Middle-aged seed tubers cure for 7-14 days.
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Older seed or varieties prone to dormancy (like Atlantic or Kennebec) need the full 2 weeks.
During the curing period, cool the cut seed potatoes to 38-40°F with 85-95% humidity. Good airflow prevents CO2 buildup but avoid drying the seed out. After curing, cut seed can be held for planting up to 4 weeks if properly handled.
Handling Cut Seed Potatoes for Maximum Viability
The key to maximizing how long cut seed potatoes last is being gentle! Rough handling causes bruising, which invites rot and decay. Here are my tips for keeping cut seed potatoes in top shape:
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Store cut seed in shallow trays, 6 feet deep max.
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Avoid dropping pieces or throwing them around. Impact damages cut surfaces.
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Transport seed carefully to avoid knocking piled seed together.
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Keep seed cool (38-50°F) but allow 2 days to warm up before planting.
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Maintain proper humidity around 85-95% to prevent drying out.
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Apply seed treatment as a safeguard against disease organisms.
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Warm seed tubers before taking them from storage to avoid condensation.
Follow those handling guidelines and cut seed potatoes can last 4-6 weeks in proper storage. Gradually warming the seed for planting 2 days ahead helps too.
However, cut seed viability declines over time. After 6-8 weeks, chances of rot and weak sprouting go up. I try to avoid cutting seed more than 1 month before planting if possible. For best results, cut seed potatoes 1-2 weeks before planting day.
Watch for Signs of Trouble
No matter how carefully you handle cut seed potatoes, issues can still creep up. Keep an eye out for these warning signs that indicate your cut seed isn’t storing well:
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Shriveling or wrinkling – seed is dehydrating
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Mold or soft wet spots – disease setting in
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Sprouts drying out or weakening – seed aging
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Greening of the cut surface – exposure to light
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Stuck together seed pieces – lack of air circulation
If you notice those problems in your cut seed potatoes, isolate and discard the damaged pieces. Cut and cure a fresh batch of seed tubers as needed. Letting diseased seed go into the ground will lead to a weak crop plagued by disease.
Key Takeaways on Cut Seed Viability
To sum up this article, follow these tips for maximizing how long your cut seed potatoes will last:
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Cure freshly cut seed 1-2 weeks before planting
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Handle seed gently to prevent bruising
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Maintain proper storage temperature and humidity
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Allow 2 days to warm seed tubers before planting
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Watch for shriveling, mold, and other warning signs
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Discard severely damaged seed pieces
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Plant cut seed potatoes within 1-2 months for best viability
Curing Cut Seeds Before Planting
One way to fight disease is to let your seed potatoes cure for a few days after you cut them and before you plant them. The cut potatoes only need to be left in a dry, airy place out of the sun for two or three days to cure. The cut side of the potato will dry and harden and get a leathery texture. This makes the cut side of the potato stronger and keeps diseases that come from the soil away from the plant.
How To Cut Seed Potatoes
How long do seed potatoes last?
The answer largely depends on the storage conditions and quality of the original seed potato. Generally speaking, cut seed potatoes should be planted within 1-2 days of cutting in order to ensure maximum yield potential. If you need to store your cut potatoes for any length of time, there are a few things you can do to extend their lifespan.
How long does it take for seed potatoes to cure?
One way to combat the disease issue is to let your seed potatoes cure for a few days after cutting and before planting. To cure them you simply need to let the cut potatoes sit in an airy, dry place that is out of the sun for 2 or 3 days. The cut side of the potato will dry and harden and get a leathery texture.
How long do cut seed potatoes last before sprouting?
Generally speaking, properly stored cut seed potatoes should remain viable for two to three weeks before sprouting occurs; however, if conditions aren’t favorable during storage time frame decreases significantly down to just a few days or less.
How long can seed potatoes be stored before planting?
However, it’s important to know how long they can be stored before planting. The answer largely depends on the storage conditions and quality of the original seed potato. Generally speaking, cut seed potatoes should be planted within 1-2 days of cutting in order to ensure maximum yield potential.