Potato: What You Should Know About Potato Fruits

Berries collected from domesticated potatoes
Potato berries


  • Potato plants sometimes flower and then form berries.
  • Potato berries form only in favorable weather and with sufficient pollination.
  • Potato berries contain seeds that you can grow.
  • The berries are toxic and should not be eaten.
  • There is not usually any reason to remove the berries from the plant.
  • Seeds from berries that fall and rot can sometimes germinate in place.
  • Berries can be harvested for seed after a minimum of six weeks.

Whenever spring and summer weather has been unseasonably cool, people report seeing something unusual on their potato plants: berries.  Potato berries look a lot like small, green tomatoes.  These are known variously as seed balls, potato apples, potato tomatoes, or simply as berries, which is the most accurate description, botanically speaking.  Tomatoes and potatoes are both members of the same genus, Solanum, and they both produce berries.  We eat the berries of tomatoes, but we don’t eat the berries of potatoes because they are somewhat toxic.  Unlike tomatoes, potato berries are small, rarely much exceeding an inch in diameter.  Most remain green at maturity, but some varieties turn purple.

If you were surprised to see berries on your potato plants, you are not alone.  Potatoes are normally grown from seed tubers, so many people have never given much thought to the matter of actual seeds of the potato plant.  When you grow a plant from a tuber, it is a clone.  Every plant of a particular potato variety is, in a very real sense, part of the same original plant.  But potatoes can also reproduce sexually.  They flower and, if the flower is pollinated, later produce a berry that can contain several hundred true potato seeds.  Unlike planting a potato from a tuber, a potato plant grown from seed is new and unique.  Potatoes are not true breeding like many crops that are grown from seeds.  Seed grown potatoes will have different characteristics than their parents.  This is the foundation of potato breeding.  New varieties are first grown from seed and then propagated from tubers.

Potato berries are most commonly green

It can be a little difficult to find information about potato berries and seeds because we call the tubers that we plant “seed potatoes.”  There is a lot more information about seed potatoes than potato seeds, but search engines can’t really tell the difference between the two.  We call potato seeds “true potato seeds” or TPS to better differentiate.  They may also be called “botanical potato seeds.”

Even if you have grown potatoes for years, you might never have seen berries.  For one thing, you might simply have never looked for them if you didn’t know about them. There are several factors that are important to berry production:


Potatoes are native to cool, temperate areas in South America.  The most significant ancestor of the modern potato is the group of potatoes that were domesticated in coastal Chile.  Those potatoes, in turn, were produced from varieties native to the Andes.  Both areas share a cool and often humid climate.  Potatoes flower and form berries best under their native conditions, so when the temperature stays under 80 degrees with high humidity, plants tend to flower much more abundantly.


Many modern potato varieties have sterile pollen.  These “male sterile” varieties will not produce berries unless there is another fertile variety present that can pollinate them.  People tend to notice berries when they begin to grow multiple varieties, which can cross pollinate.  If you have grown the potatoes or true potato seeds that I offer, you are much more likely to see berries on your plants than you would be with commercial varieties, because I have excluded most sterile varieties.

Potato berries can also be blue, becoming almost black as they ripen


Potatoes are most effectively pollinated by bumblebees, which perform a specialized “buzz pollination,” where they vibrate their wings very quickly to dislodge pollen from the flower.  Other pollinators, like honey bees, don’t do this, so they are poor pollinators for potatoes.  If you have noticed more bumblebee activity, that might explain the sudden appearance of potato berries.


Humans have selected potatoes for heavy yields of large tubers.  In contrast, wild potatoes often produce a much greater yield of berries than tubers.  Through those thousands of years of selection, we probably didn’t care much about berries, since we don’t eat them or use them to propagate the plants in most cases.  As a consequence, domesticated potatoes have often “forgotten” how to reproduce sexually.  Many varieties rarely or never flower even in ideal conditions.  Some flower but fail to hold their berries.  Something like 10% of modern potato varieties are reliable flowerers.


Potatoes accumulate diseases, particularly viruses, over time.  Those viruses decrease the yield of the plant, but they also often decrease the ability of the plant to flower.  You are more likely to see flowering with fresh, certified seed potatoes than you are with a variety from which you have saved tubers for multiple years because certified seed tubers most likely have a lower disease burden.

Common Questions About Potato Berries

Red potato berries are pretty uncommon, but also possible

How Toxic Are The Berries?

Potatoes form toxic substances called glycoalkaloids.  They are produced in small amounts in the tubers, but typically much higher amounts in the foliage and the berries.  Berries have about 10 times the level of glycoalkaloids as the tubers of commercial varieties (Friedman 1992) although the levels in both berries and tubers vary significantly with variety and growing conditions.  Potato tubers are considered safe when they contain less than 200 milligrams of glykoalkaloids per kilogram of tubers.  Berries may range in glykoalkaloid content from as little as 177 mg/kg to 1350 mg/kg or more (Coxon 1981).

Some people begin to experience symptoms of toxicity at about 1 mg per kg of body weight (Ruprich 2009).  Based upon those amounts, a sixty kilogram (132 lb) person could consume somewhere between 40 and 300 grams (1.4 to 10.5 ounces) without developing symptoms, depending on the actual level of glykoalkaloids in the berries.  An adult who eats a few potato berries might not have any symptoms or might spend an unpleasant few hours with vomiting and diarrhea.   Of course, potato berries are much less tested than tubers, so you should definitely contact your doctor if you have eaten potato berries.  The situation is likely to be more serious for children, since they can more easily accumulate a high dose for their body weight, so make sure that they understand that the berries are not edible.

It is possible that some potato berries may be edible when fully ripe.  As noted above, some fall into the glycoalkaloid range that we would consider safe for tubers.  Luther Burbank once bred a potato that he called a “pomato” that had large, light colored, sweet berries.  Of course, the fact that he thought that they tasted good doesn’t mean that they still weren’t toxic if eaten in quantity.  That is probably why there hasn’t been much follow up in breeding for potato berries – the testing process probably wouldn’t be very pleasant.

Most potato varieties form only a few berries, but some can produce hundreds. These berries were all collected from the same plant.

Berries do not affect toxicity in the rest of the potato plant.  The tubers are just as edible as always.

What Do They Taste Like?

I have tasted quite a few berries.  You won’t poison yourself by tasting and spitting them out.  There isn’t that much glycoalkaloid in them.  I still don’t really recommend that you do this though and you should make certain that children don’t.  Unripe berries taste a lot like green tomatoes, but have a much stronger bitter aftertaste.  As they ripen, they become bittersweet, and, when fully ripe and soft, they can become surprisingly tasty, something like a mix of melon and tomato, not that different from a pepino.  As noted above, It is possible that fully ripe fruits of some varieties are safe to eat.  The problem is that there is no way to know for sure without experimenting on yourself, short of a lab equipped to do glycoalkaloid analysis.  So, if you are feeling adventurous, you could try tasting a ripe berry, but don’t swallow it unless your health insurance is paid up.

Should I Remove The Berries?

Probably not.  It isn’t a common practice.  If you have young children and you are worried that they might eat the berries, that is probably the best reason.

Berry production may reduce tuber yield by diverting resources into sexual reproduction (Tekalign 2005), but the difference is generally not significant.  Tuber production and berry production both begin following flowering, so there is competition for the plant’s energy between the two.  In practice, farmers do not normally perform reproductive pruning of potato crops, even with varieties that fruit heavily, since the cost of the work involved would exceed the value of the difference in yield.  In general, the heavier the berry production in a variety, the greater the potential reduction in yield.  If you are only growing a few plants, you could remove flowers before they form berries and you might get a little boost.  Most varieties produce so few berries that you won’t see any difference.

What Are They Good For?

As with many plants that we normally propagate from vegetative parts, like tree and small fruits, asparagus, rhubarb, sweet potatoes, and others, the seeds of potato plants don’t grow true.  That means that when you grow a plant from those seeds, the tubers are not the same as what you started with.  In fact, every plant grown from seed is an entirely new variety.  Very few will be as good as what you started with when compared across a wide variety of traits, but many will be perfectly acceptable to home gardeners who like to be a little adventurous.

When Do You Harvest the Berries?

If you want to harvest the berries and extract the seeds, the best approach is to wait until the berries ripen and fall of the plant.  Just collect them off the ground.  If you have problems with pests eating the berries, then you can pick them after they have hung on the plant for six weeks, when they are still fairly hard and unappealing to animals.  You can also put a mesh bag over the berries as they are forming to protect them and keep them from getting lost.  Any berry in excess of 1/2 inch diameter probably has viable seed, but the seeds become larger and produce better seedlings when left to mature as long as possible.  Once picked, leave the berries to ripen until they are soft to the touch before extracting the seeds.

A pile of several hundred true potato seeds (TPS)
Seeds extracted from potato berries

Will The Berries Lead to Weeds?

Maybe, but it is more likely that you will have problems with plants growing from tubers that you missed than from seeds.  If you don’t collect the mature berries and allow them to fall on the ground, some will rot and release their seeds into the soil.  If you live in a climate that doesn’t have long, deep freezes, those seeds can survive the winter and germinate.  Normally, because the number of berries is small and the survival rate is low, volunteer seedlings are unusual.  If you have a variety that produces lots of berries and you live in a mild climate, you could get lots of seedlings.  This has happened here on occasion.

How Do You Get the Seeds Out of the Berries?

There are several ways to go about this.  The simplest is to wait until the berries are fully ripe and very soft and just squeeze the seeds out.  You can also use any method for saving tomato seeds.  If you want very clean seeds that are suitable for long term storage, you can extract them with a blender and treat them with detergent to break down substances that inhibit germination.

How Do You Grow True Potato Seeds?

The process overall is similar to starting tomatoes from seed.  For more information, see our growing guide for true potato seed.


64 thoughts on “Potato: What You Should Know About Potato Fruits

  1. Ken Wood says:

    I have heard that the Chinese are raising consistent potatoes from true seed. Do you know how they managed it, if true?

    For our farmstead use, I prefer keeping the genetic possibilities of growing multiple varieties and saving TPS for a day when I have too much disease buildup in my tubers. As that point approaches I would grow out a bunch of seedlings and start the winnowing process to identify a few with traits that work for me in this (changing) climate. For example, though I live on an island in the Salish Sea (Pacific Northwest) we are having ever dryer summers and I really need a late, keeper potato that can get it’s vegetative growth in early, before the summer drought begins but not keel over from the lack of water and then put on some good tuber growth when the fall rains start up. I help somewhat with cultivation practices: straw mulch, deep planting of tuber pieces, etc. But there seems to be a wide variety of drought tolerance in the 50+ varieties I have grown (mostly from Tom Wagner’s breeding projects) Unfortunately, the very best drought test producer, Black Ball, has so much glycoalkaloid in the tuber that I can’t eat it! Big beautiful dark, dark blue black potatoes with not a drop of irrigation, but inedible! Ozette was 2nd best producer in the drought tolerance test and no toxin problem.

    Speaking of the Ozette potato, the story we have is it has been grown by the native people of the Olympic peninsula since the 1500’s (they actually say “forever” but there is no evidence any further back than post Spanish contact) My question to you is: how did they manage to keep growing from tubers for 500 years without disease building up to terminal levels? If it was by growing from TPS, how is it that Ozette potatoes are so consistent?

    I just discovered your site from the Plant Breeding for Permaculture facebook page and I’m looking forward to reading all your posts! Thanks for sharing your adventures in plant breeding!


    Ken Wood
    Orcas Island

    • Bill Whitson says:

      Hey Ken. I don’t know about the Chinese, but potatoes have been grown as a field crop from true seed since at least the 1970s. It’s just not a popular option because the amount of work required to start seeds and transplant seedlings greatly exceeds that of dropping a seed tuber in the ground. Some lines have been bred so that the progeny are all very similar, even though they aren’t genetically uniform (which is basically impossible with potato). It has advantages where there is not a sufficient or affordable supply of disease-free seed tubers, but that isn’t the case in most of the bigger potato producing countries.

      Your Black Ball sounds like a good candidate for further breeding. If you cross it with varieties that have reasonable drought performance and less bitterness, at least some of the progeny should come out in the middle on those traits. It is unusual for domesticated potato to have very high glycoalkaloids, so it probably doesn’t need to be reduced very much to drop into the palatable range. We have very similar climates in the summer – we often have no precipitation other than fog from June to September.

      Ozette is thought to have been in this country since about 1792, when the Spanish built a short-lived fort at Neah Bay. Genetically, it groups with Chilean potatoes, so it was likely brought along from Spanish Chile. The Spanish left the next year and the potato stayed. It’s longevity can likely be attributed to the lack of potato pathogens in the area, other than whatever it might have brought. It doesn’t have very good virus resistance in general, but the Makah were (and still are) a long way from any major potato production areas. It does seem to be very well adapted to our climate, which isn’t too surprising since it has had more than 200 years to adjust. Genetic analyses of this variety at the extents of its range – well up the coast of BC – haven’t found much difference, so it isn’t likely that it was propagated from true seed. It is also a very tricky variety to get berries from, in general. It is probably part of an unbroken line of vegetative propagation going back before it landed on this continent.

  2. Julie Eros says:

    My daughter and I just planted a tuber in early spring it yielded 2 plants that’s covered in berries. The tuber was just a potato growing ears from the large bag we got at a local shop we are going to try and grow some more plants from true potatoes seeds hopefully we get some great tasting potatoes

    • bill says:

      Well, true potato seeds are the basis of potato breeding, so there is actually quite a lot of work done with them. Major potato breeding programs sometimes grow hundreds of thousands of plants from seed. As for why it isn’t more common among non-specialists like gardeners, farmers, and nurseries, I think knowledge has been the biggest barrier for a long time. Until recently, almost every gardening book that even mentioned true potato seeds said something like, “you can grow potatoes from seed, but they won’t be any good so don’t bother.” That really couldn’t be further from the truth. We have to show people what is possible when growing from seed so that they will be interested to try it and we have to give them good instructions so that they will be successful. There has been a huge increase in this kind of information in the past decade, so I expect that growing potatoes from seed will continue to become more popular.

  3. Gilly says:

    Hi, I was very interested to read this: I have been growing potatoes in potato “sacks” on and off for a few years in small amounts. I was looking at the very pretty flowers today and suddenly saw the “berries”, maybe a dozen or so of them. I’ve never seen such! My husband said maybe I’d dropped some tomato seed accidentally, but I compared the flowers, leaves and stems to my tomatoes and knew they were different. I DO remember seeing potatoes flowering once or twice in the past but have never seen berries before. I shall try and grow the seeds. The potatoes came from a supermarket.

  4. Deirdre Helfferich says:

    I regularly get potato flowers and berries but pinched them off to encourage tuber production. Glad to know that’s not necessary! There is a variety I love called Purple Viking, with deep purple skin and bright white flesh with deep purple streaks. Good for baking and for mashed potatoes. I haven’t been able to find it since I moved out of Alaska, though.

    • bill says:

      Are you asking if you can plant the seeds directly from the berries, without any processing? You can, but the germination rate is usually not as good if you have not removed the gel from the seeds.

  5. Harjit says:

    So how to keep seeds of potato during summer (in cold fridge or something if yes than how long can we keep that) ?

  6. Eliot Smith says:

    hi am in ireland down along the East coast but grew potatoes further in, in a part of West wicklow, last year and had some Roosters that were left in at my place in Wicklow and had chitted in my absence , then some Record potatoes, found at the bottom of a cuboard in out mobile down in kerry, and they had really chitted – and on way back from Kerry the car blew a gearbox and the potatoes were in the car in Michelstown for a week or two while it got repaired – i also had Queens and some Kerrs Pinks, and some i dug up from the patch when digging it over – so ended up with Roosters both dug up and from a bag in cupboard, Queens and Kerrs Pinks from dug up when prepping the area and from a bag left in cupboard and the Records all the way from kerry (with a delay in between ) Well I got a few berries on probably the Record plants which turned out really good large tubers and delicious – and got into the True Potato seed world – oh also my sister had a few potatoes that just came up where she had potatoes the year before and she also got berries and whilst there one night saved a few So have planted the seeds and have all sorts of little seedlings( they are spindly but growing now ) some with bronze stems some with a habit of sending additional stems out all somewhat different and its going to be interesting to see what develops — this year also sowed potatoes down in my place in West Wicklow just before lockdown ( due to the Virus) some came from the soil and were chitting in the soil, mixture of Rooasters Queens and Kerrs Pinks again and came up the morning after the lockdown was introduced and have found some potatoes coming up from my dads efforts last year and they have gone in here – near the coast near Bray Co wicklow – they were mid sason earlies but also did some roosters as well here – should be very interesting to see if any berries appear Maybe the potato plants are setting pods more readily due to changes in the climate as we are getting it very warm tomorrow then a period of cold and so I think maybe we will see more berry set on potatoes in the years to come —– it was a really difficult year here for the potato harvest, with the soil at the time of the harvest being way too wet for the tractors and machinery to get the potatoes from the ground – have not seen berries like last year and think the potato plants are responding to unusual weather patterns and are hedging their bets on trying to ensure they will produce the year after anyhow its going to be a long summer and be very interesting to see the results

  7. Mike Vang says:

    I’m a beginner gardener. I was reading up on how to save seeds. I discovered that tomato seeds require fermentation as do other kinds of seeds to increase its germination rate. I wonder if fermenting true potato seeds might increase its likelihood of germination. Just a thought seeing how tomatoes and potatoes are from the same family.

    • bill says:

      Much like tomato seeds, potato seeds have germination inhibitors that can be removed through fermentation. These break down naturally in time, but you can get better early germination by fermenting or otherwise cleaning the seeds.

  8. skye says:

    Have you ever seen potato fruits turn gold? My weird new variety that has tomato-looking leaves has fruits that look like small sungolds. They taste different though and are filled with seeds.
    There are definitely small purple tubers but my online gardening group doesn’t believe me. Everyone thinks that I mixed in a tomato seed by mistake. I was so excited to share my experience but it didn’t turn out positive. People say that it’s not possible for the fruits to turn gold.

    • bill says:

      Fruits can turn somewhat yellow once they are fully ripe, but I don’t think I have ever seen one that is as yellow as most yellow tomatoes. Drop by our Facebook group and post some pictures. We ought to be able to figure out what you have there.

  9. Norabally says:

    Delighted to have found all this info! Have been growing a few potatoes in West Cork, Ireland since a few years – this year I got a few potatoes from some Spanish fishermen, which I chitted and then planted in a raised bed. We had an extremely warm and dry April/May but a cool and wetter June. I was surprised I had no blight, as normally I try to plant a blight resistant variety here, as it is a very sheltered site. I did have a small pot with cherry tomatoes near the high bed so when I saw tomato looking green fruit on one of my potato plants I was very puzzled, and nobody believed me until a friend mentioned they are the same family, and have maybe cross pollinated…Now I think I understand that this is not the case but wondering when and how to save these “true potato seeds? What is meant by fermentation process in regards to germinating these seeds? Can I try germinating them now sometime maybe in the greenhouse for a late crop experiment. Or will I save them for next spring, and how do I know if the potatoes then, if successful are not too high in alkaloids? My youngest son is studying Bio-Chem maybe there is a simple way to test them, or can you taste the solanine(?) content eg bitterness… The berries are currently still green and the size of a good size cherry tomato. I don’t know what the Spanish variety of spuds are called on which the berries are growing but they have a wonderful good size creamy potato, that melts in the mouth. All these potatoes are ready for digging now bit by bit but I can leave this one plant for a while, if I need to. The other variety in that bed are Aron Pilot, a very early traditional variety. I am not on fb but would appreciate some feedback, thank you.

    • bill says:

      Leave the berries on the plant as long as possible, but at least six weeks. You can find instructions easily for fermenting tomato seeds and it is the same process. In short, you can squeeze the contents of the berries into some water and then leave it in a warm place for a few days to ferment. This will help to remove germination inhibiting compounds from the seeds. They will germinate best after a year, but you can get some germination earlier if the seeds have been fermented or cleaned with detergent. Any varieties that have high glycoalkaloids will be bitter. Don’t keep bitter varieties. They will usually be rare from domesticated potatoes. Arran Pilot is a fertile variety, so it would not be surprising if that is the pollen parent.

      • Norabally says:

        Thank you very much for the prompt reply. I would like to compliment you on your wonderful website, and look forward to reading more of it and listening to your podcast, when I am not busy keeping nature at bay here. I will forward this link to many of my gardening friends. Keep up the enthusiasm and fun ’cause it mightn’t save the world but it sure made my day :-)

  10. Smith says:

    Hi, if the potato plants produce the fruit/seeds (that are poisonous), is it still ok to eat the potatoes?
    Thank you

  11. Diana says:

    Dear Bill,
    I pulled apart a fresh flower and now think that what I found was stamen/stamens (?) not seed. Slightly mortified in showing my ignorance with my former question, but there it is! Thanks for your time nonetheless!

    • bill says:

      It sounds like you opened a flower bud. First the flower has to be pollinated, then it forms a berry. The berry contains the seeds. It takes about two months from when the flower opens to when you have a mature berry with seeds in it.

  12. Kim says:

    How interesting! I live in growing zone 3a. I am wondering how early I should start the seed to have it ready to transplant out in mid-May.

    • bill says:

      Chitting is the process of allowing potatoes to sprout a little before planting. Usually, this is done by leaving the seed tubers in a warm, sunny location. When the eyes begin to bud, the tubers are chitted and ready to plant. By chitting the potatoes, you get earlier emergence than you would by planting dormant tubers into cool soil.

  13. molly says:

    It’s great to learn the real origin of Ozette’s arrival – at a Spanish settlement at Neah Bay in 1792. I’d read somewhere that it might have come from Francis Drake, but nobody seems to know exactly where he landed, and that he would have stayed long enough to have given potatoes to local people seems hard to prove, as it’s not in his records. I grew it one summer in Falmouth MA, on Cape Cod, and it did quite well.

  14. JT says:

    I’m only a second year gardener, and this is my first year growing potatoes. We live in a suburb of Denver, Colorado, which is in zone 5a for plant hardiness. This year I planted two rows of a red potato, two rows of Yukon Gold, and two rows of fingerling potatoes (which came from the grocery store). I was shocked to see how lush and green (and large) potato plants were, and then I noticed the potato blossoms. I had no idea potatoes blossomed, but I took several photos because they were quite pretty, delicate purple flowers. Today while cutting back the remainder of the potato plants that were dying back we discovered what looked like small green tomatoes. After some Googling I came across this blog post and I am shocked to learn that these are potato berries! I intend to attempt to germinate the seeds and grow them because I’m excited to see what cross I’ve accidentally created

    • bill says:

      Highland Colorado is potato country. One of the biggest potato breeding programs in the country is in the San Luis Valley. And, of course, in southern Colorado, you also have the native potato Solanum jamesii. No surprise that you would get some flowers. Yukon Gold is one of the more reliable berry producers among commercial potatoes. Good luck!

  15. Sue says:

    Does anyone know what happens if you simply put the berry pod back into the ground. Do they just decompose and seed? Can this cause a problem with toxins in the soil?

    • bill says:

      Best case, you get a few hundred seedlings all growing in an area the size of a berry. Worst case, they rot and you get nothing. If you are serious about growing potatoes from seed, it is much better to extract them. Potato toxins don’t persist in the soil or else every compost pile full of potato tops would be a toxic waste dump.

  16. Joe Snow says:

    I’ve heard that trying to grow potatoes from seed is very hit or miss, as they don’t reproduce true to type this way. Growing from seed potatoes will yield a genetic clone of the parent plant that produced it, which may have gone through many generations of breeding to add to the positive qualities and eliminate or reduce the negative ones. You’ll be starting from scratch if you try to grow using seed, and could end up with a bad crop with poor disease, cold and pest resistance, then your time will have been wasted when your plants either die, or the yield is lower than you hoped for. The seeds may not grow at all. Seed potatoes are almost always going to be the best way to go.

    • bill says:

      That is a pretty good summary of the situation, but it focuses on the downsides and ignores the upsides of growing from seed. This is what I would describe as the conventional position as it has been communicated in most gardening books published after WW2. The proposition here is essentially that the home garden is a farm, where only production matters, and you should grow what the farmers grow. This is a value proposition though and it is possible to have different values. For example, my garden is an experiment station, where I create new things and grow what I cannot buy from a farmer. I value exploration, novelty, and wonder more than I do production, so I grow from seed. There is a lot of information on this site about growing from seed and this is a good place to start if you want to learn more.

  17. Jenna says:

    Hi, I have just started growing my GMO-free potatoes. I have noticed bumblebees hovering over their flowers. I have not had my first harvest yet. To keep them GMO-free, do I continue to grow from my tubers.

    If I use the seeds (if I get any), would that risk my GMO-free potatoes cross-pollinating with GMO potatoes grown by one of the neighborhood’s residences?

    • Chris says:

      My understanding of gmo is this. There is nothing inherently wrong with a genetically modified plant. The issues revolve around what the plant is genetically modified to perform.
      The issues I have with certain gmo crops, is when they are genetically modified to live through applications of toxic products, designed to kill weeds or pests. Now when you consume the plant, you are consuming a plant that has toxic residue on it, and had grown in and fed off of soil that is holding the runoff of toxic applications.
      Just a little food for thought on the gmo subject.
      After all, isn’t cross breeding plants a form of genetically modifying a plant?

    • bill says:

      Probably not. Glycoalkaloids don’t start to break down until 338 degrees F and it takes a while. You start to get some measurable breakdown when cooking potatoes at 400F, but by the time you got them down to safe levels, I doubt that there would be much left of the berries.

  18. Rich says:

    Hi! I’m living in Colorado Springs, and I’ve been trying to propagate TPS for a couple of years now, but can’t get the berries to set. (I get plenty of flowers, but no fruit.) I’ve started and gotten tubers from a couple of your seed mixes, but sadly no berries. I see from some of the comments above that I may need to be starting earlier in the season (it occasionally gets above 80 in June, and this year’s been even warmer), but precisely how humid does it need to be to encourage fruiting? Does it have to be ambient humidity, or can I just water the soil more? Any other advice that I might be able to try? Thanks!

    • bill says:

      Hey Rich. Have you tried doing any hand pollination? It is possible that you don’t have the right pollinators. If you have tried hand pollination and still don’t get berries, heat is the most likely reason. Humidity helps, but potatoes will fruit in dry conditions. My best advice is to keep trying. Many people go for years without seeing any berries and then suddenly get a bunch of them in a favorable year.

  19. Rich says:

    I was wondering about pollination. I’ve been watching the past couple of days, but although I see plenty of bees on the various weed flowers in the yard, I have not seen any on the potato flowers. Was there a how-to on hand pollination here somewhere? This’ll be a first for me.

    • bill says:

      It is described in a few places, but I really should have a blog post on the subject. Get yourself a cheap electric toothbrush. The vibration is similar to what bumblebees do with their wings to dislodge the pollen from the flower. Hold a container or even just a flat surface like a cell phone screen under the flower and then apply the toothbrush to the back of the flower for a few seconds. You should see some fine, white powder fall out. Some varieties are more fertile than others, so if you don’t get anything, try a different plant. Go to another flower on a different variety and dip the bulb at the end of the stigma (the little green part that sticks out of the cone of anthers) into the pollen. You can make it more complicated than that, but that is enough to get the job done. Good luck!

  20. Ed Gorman says:

    So stoked. I’ve been growing for a couple years. Bought different seed potatoes this year and bam berries. Confused at first I’m stoked great info

  21. call me ishmael says:

    so they are called ‘true potato seeds’, but they don’t come true to the parents
    makes sense in our new normal where up is down, and war is peace

    thanks for the info, we have many berries this year to save seed from
    there is nothing quite like finding a new variety for your area (without waiting 7 generations for stability like a tomato, simply save the best tubers)

    • bill says:

      There are tradeoffs though. Because tetraploid potatoes are so genetically complex, the odds of getting something that is as good as what you started with are much lower. A breeding program to produce a new tomato might take eight years, but typically requires a fairly small number of plants per generation and it can be evaluated along the way, particularly in the later generations. To breed a new potato for the commercial trade may require growing 100,000 seedlings. You can do that in a year if you have the size and manpower, but then you still have only promising new varieties that must still be evaluated. So, in the end, it works out about the same. A hobbyist can select a nice potato for his garden in a couple years, but a hobbyist can also accept a new seed-grown plant before it reaches complete stabilization, so the differences aren’t as huge as they first appear. But, sometimes you certainly get lucky and find a great variety right away.

  22. randy hutchison says:

    Hello Bill, have you ever recreated Burbank’s species cross that produced the tasty whitish fruit? It had been about 50 years since I read his account, your mention of it got me curious. You have an interesting page! Randy

    • bill says:

      Hi Randy. I haven’t tried, but I have observed plants with large berries and have tasted berries that lacked any bitterness when fully ripe, so I assume that it wouldn’t be that difficult to produce a new variety that combines those traits. Whether there would be any demand for such a thing is anybody’s guess, but people do seem to like the garden huckleberry/wonderberry, which is another Solanum with berries that have high glycoalkaloids before they are fully ripe.

      • Cathy says:

        Oh my – last post Nov 2022! I am a serious beginner gardener with a 90 year old Dad teacher in North West Ireland. Went out to collect some spuds to share with the neighbours as they growing and sharing Cauli and broccoli and cucumbers and I am sharing radish’s , carrots and potatoes. Like a previous writer saw a few things that I swear were tomatoes. From smelling and rubbing the leaves to tracing the plants stalks to roots and still couldn’t fathom how a tomato plant had found its way into the potatoes …..a few pictures later and now at 23h32 scouring through Ms Google I found this. Thank you for the sharing and I really like the and all exploration concept and look forward to learning how to get the seeds into their next phase with wonder and hope.

  23. Randy says:

    With the internet invented, it seems there is renewed interest in obscure plants/fruit. I’m embarrassed to say my mouth started to water when I reread Burbank’s description of the high sugar and acid flavor of the new fruit! Your pepino flavor comparison caught my attention. Regards

  24. paul von behren says:

    I’m looking for certified heirloom potato seeds – not seed potatoes. Do you have or can you advise as to where I can purchase them? Thank you

    • bill says:

      There is no such thing. Nobody certifies true potato seeds. In fact, the diseases that certification programs are designed to screen out are almost entirely irrelevant when growing from seed.

  25. Lee says:

    I am always amazed by warnings that potatoes (or apples, or peaches, or pecans) do not come “true” from seed. Neither do humans. Not only do I differ significantly from both my father and my brothers, but I am also not even the same gender as my mother!
    What are we expected to expect from sexual reproduction?

    • bill says:

      Well, most domesticated plants do grow true from seed, so it isn’t a crazy expectation. The plants that don’t grow true are infrequently grown from seed. It is possible to grow a garden full of different vegetables for many years and still have only a vague idea of how genetics factor in.

  26. Robert Harvey says:

    I just wanted to say thank you for you info on TPS . We have 6 different varieties thatwe grew from seed potatoes and only one of them has grown the berries. I am very interested inseekng what they produce next fall.
    Have bookmarked your site so i can keep your posts and insights on hand for when we harvest our potatoes and TPS .

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