Cutting Seed Potatoes before Planting is a common planting practice that will save seeds and produce more plants in your garden.
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 usually start planting potatoes without any frost protection about 2 weeks before your last frost date. (To learn what garden zone you live in check out this post)
Cutting Seed Potatoes
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.
If you are looking for a quick answer to your cutting seed potatoes questions and how to cut seed potatoes then watch the video I filmed above as part of my 5 minute Friday video series. If you want more details on cutting seed potatoes then read on!!
Potato Anatomy 101
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 when you have a larger seed potato like this one in the photo above, it may have 15 or more sprouts. It is possible to cut this seed potato into 2 or even 3 pieces, dividing the sprouts between each chunk. Each of the pieces will then sprout, grow and become its own potato plant.
Cutting Seed Potatoes
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. I also like to be sure that each piece has at least 4 or more eyes left on it after cutting. So most often I only cut the seed potato into 2 pieces. A particularly large seed potato may get cut into 3 pieces. There are a few folks out there that will disagree with this and say you can cut the seed potato into much smaller pieces with only 2 eyes. But I feel like you give the potato plant the best chance for success with chunky pieces with at least 4 eyes.
To cut your seed potatoes simply use a sharp knife, select a line that will give each piece at least 4 eyes and cut off a big chunk! Be careful to not cut through any of the eyes as this will destroy the future sprout. It’s that simple, suddenly 1 seed potato becomes 2 or 3 allowing for more potato plants from less seed. After cutting seed potato I like to have a piece that is at least 2 or 3 inches long and wide.
Disease problems
If you live in an area where there are soil born viral or bacterial diseases that affect plants in the Solanaceae family (Potatoes, Tomatoes, Peppers & Egg Plants). 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. The idea is by cutting your seed potatoes you open them up to more vulnerability to soil born problems.
I have personally never had any problems with diseases on my potatoes that have been caused by cutting the seeds. But there is that possibility. So if you have had potato disease problems in your garden in the past then please skip cutting your seed potatoes. Also, keep your garden clean, any time you have diseased plants in your garden pull them out and dispose of them in the garbage. Do not put them in your compost bin. Practicing good crop rotation will also help keep disease problems down in your backyard garden.
Curing Cut Seeds Before Planting
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. This “hardens” up the cut side of the potato and helps keep soil born diseases out of the potato plant.
Planting after Cutting Potatoes
Once the potato seeds are cured (or right away if you are not curing) simply plant your cut seed potatoes with the cut side down and the eyes facing up and cover them with around 2 or 3 inches of soil. Then as the season progresses continue to mound soil up on the greens as they emerge.
To learn more about mounding your potatoes you can read this post.
Cutting seed potatoes is a quick and easy way to double the number of seeds you have and increase the number of plants for a much larger harvest this fall!!
Learning how to grow Early Potatoes
I used to cut my potatoes and planted them 12 inches apart. I usually got a return of about 6 to one over what I planted. I started planting the whole potato, medium sized ones, at 16″ apart and have got as large a crop as 12 to one, but not always of course. Depends on the year and conditions.
How long does it take to get potatoes or when do you know they are ready to harvest
It depends on the variety, any where from 90 to 120 days. Here’s a link to a post that tells you when to harvest:
https://ourstoneyacres.com/when-to-harvest-potatoes
We always look for the soil to crack then we would dig.
As it shows in this “lesson”, once the plants start dying, might as well dig them. I live in zone 6, upper mid part of Kansas. Our last approximate frost day is 15 April. I plant March 17th, St. Patrick’s Day. I usually dig mine up the last week of June. I grow Yukon Gold and a Blue potato, which has four times the antioxidants.
Thanks for sharing your knowledge and experience. We have always cut our potatoes, but it’s good to know that 4 eyes give better success. We haven’t always seen a lot of potatoes under every bush, this could be the reason for that.
Eager to learn more about gardening
i put my cut potatoes in the sun to dry. they are turning brown now. can i still plant them or should i throw away and start again? thanks for helping.
As long as the eyes and sprouts are still in good shape they should be fine.
Here’s an odd question that no one online seems to have addressed. How long after you harvest a potato do you have to wait to replant them, if you have to wait at all? Here in south Florida, our potato season goes from October to April/May. What I plant in October, I harvest the first week of January. I can then replant and get that crop up in April/May. Storing potatoes for seed is a bit of a challenge here because they are stored during the hot months of summer. I use a commercial refrigerator, which doesn’t dehydrate. The ones from April are growing wonderfully. The ones from January, not so much. So, if I can replant some of the harvest from January to replant, I can then have seed for the next year. It would be nice to not have to buy more seed for January if I can avoid it.
I am a garden educator in the Midwest USA. My students cut potatoes on Mon and Tues, but of course it’s been windy and rainy Wed and Thurs! Will they be okay for a week or more, or should I scrap them and start with a new batch of potatoes?
As long as they don’t look soft or rotten they should be okay.
What do you do about ants getting into your potatoes?
Are they actually causing damage to the plants? Are there aphids on your plants? The ants might be there farming the aphids.
This year I had my first real issue with ants eating potato tubers. In Florida, we have fire ants. And they eat potatoes. I lost a solid 30% of sellable potatoes this year due to ants burrowing in and eating out a large section. I’ve always had small bug damage on the potatoes themselves, but this year was something different. Depending on how much you’ve planted, DIY home organic solutions can work, but if larger, it may not. If organic isn’t a thing, bug-b-gone for vegetable gardens works on ants, including fire ants. If your garden is larger, like mine, there may be a farm organic solution. I haven’t looked yet, but most of my solutions for it come from Arbico organics.
I live in Virginia, I usually have vole problems, but not this year. However this year I lost about 15% of my potatoes from little black biting ants. They ate deep into the potatoes, leaving only the pealing in some. Still, had a tremendous crop this year unlike last year. I tried something new. I fertilized the ground with 10-20-20 before planting, tilled it in, and I planted seeds 20 inches apart. I averaged 10 nice size potatoes per hill. I have never experienced ants eating potatoes though, I cut my seed potatoes, but I did not cure them and I watered the plants during a short dry spell. I wonder if the ants will create even more of a problem in the future. years.
If the eyes on my seed potatoes get REAL LONG can I clip them (gently) before planting without hurting the potato?
No clipping them would limit growth, just plant them very carefully.
I never cut potatoes. Old and sprouted or new. Why cut them? I plant 16” between potatoes. I’m a registered master gardener. We don’t all agree on everything. Try different things on your own. Learn from your own failures and successes. But remember there are many things that can change the results like weather and soil, as well as how you water and more. Good luck and have fun!