Green potatoes are usually safe to eat — if you handle them correctly. On a boat, this question matters more than it does at home. You may be days or weeks from the nearest store, and throwing out a bag of potatoes is a real loss. So here is what you actually need to know.
Why Do Potatoes Turn Green?
Exposure to light causes potatoes to turn green. The green itself is chlorophyll, which is harmless. The problem is that the same light exposure that triggers chlorophyll production also triggers production of solanine, a mild natural toxin.
Solanine can cause nausea and intestinal upset. In large amounts it can cause neurological problems. You cannot see solanine, but it concentrates in the same places as the green color, so you always know where it is.
Can You Eat Green Potatoes?
The short answer: usually yes, with some trimming.
One report I found put the threshold at around 4.5 pounds of unpeeled green-skinned potato eaten at one sitting to cause serious harm. Another said it would take a full pound of a completely green-fleshed potato to make someone sick. You are not going to accidentally eat that much.
That said, I am not a doctor, and I will not make this decision for you. Here is what I do:
What to Do With Green Potatoes
Lightly green skin: Peel it. Solanine concentrates in and just under the skin, so peeling removes most of it. A few green spots can also be cut away. That potato is fine for most people.
Green spots or eyes: Cut them out completely — do not just break off any sprouted growth, actually dig out the eye itself. Solanine is more concentrated in the eyes than anywhere else.
Deeply or entirely green flesh: Throw it away. If the green goes all the way through after peeling, do not eat it.
Bitter taste when cooking: Trust it. Solanine tastes bitter. If a potato tastes off, stop eating it.
One more practical note: experts suggest not eating more than a couple of greenish potatoes per week. Your body takes about a day to clear trace amounts of solanine, so eating them every day can allow it to build up even if each individual potato seems fine.
If you have children aboard, be extra cautious. Children are more susceptible to solanine because of their smaller body weight. When in doubt with kids, toss it.
How to Use Potatoes That Have Gone a Bit Green
Use them in dishes where you peel them anyway — soups, stews, mashed potatoes. Do not bake them in the skin or otherwise serve them unpeeled.
How to Store Potatoes So They Stay Good
Store them correctly and they will not turn green in the first place. In a cool climate, potatoes stored properly can last two to three months. In the tropics, plan on about a month.
Your storage location needs to be:
- Cool — the cooler the better, though not refrigerated
- Dry — moisture causes rot
- Dark — light is what triggers greening; a towel draped over them works fine
- Away from onions — potatoes stored near onions will sprout faster
- Not in plastic bags — condensation forms inside and they will rot
Also avoid wire baskets or anything that creates pressure points on the skin. Bruising leads to rot.
If a potato is slightly soft or spongy but has no rotten sections, it is just dried out. It will rehydrate as it cooks and is fine to use.
Carolyn Shearlock has lived aboard full-time for 17 years, splitting her time between a Tayana 37 monohull and a Gemini 105 catamaran. She’s cruised over 14,000 miles, from Pacific Mexico and Central America to Florida and the Bahamas, gaining firsthand experience with the joys and challenges of life on the water.
Through The Boat Galley, Carolyn has helped thousands of people explore, prepare for, and enjoy life afloat. She shares her expertise as an instructor at Cruisers University, in leading boating publications, and through her bestselling book, The Boat Galley Cookbook. She is passionate about helping others embark on their liveaboard journey—making life on the water simpler, safer, and more enjoyable.
Alex Miller says
Me too! ! What’s up with that? ?
The Boat Galley says
Not sure, but it inspired a post . . .
Alex Miller says
It is very frustrating. I can’t stand throwing away food.
The Boat Galley says
I don’t throw them away, I just peel the green part off.
Alex Miller says
Me too, but the last couple of bags were small ones that would not be much left after peeling. And some large baking potatoes, so can’t Perl those either. I wonder if it has something to do with the move toward more energy efficient lighting in the stores and different light spectrums of bulbs?
Chris says
If the potatoes are boiled, don’t reuse the water in rhe galley. The toxin leaches into it. Also remember small children can experience toxic effects at much smaller concentrations than adults.
Shauna @ Momma Candy says
Thanks for the info! I looked into this a few years ago. After what I found I ended up throwing away an entire batch of breakfast potatoes.
But then just a few weeks ago I noticed the potatoes were a little green. I just hoped frying them in butter would kill of the toxins. Let’s go with that!
Visiting from the SITS Sharefest!
Dave Skolnick (S/V Auspicious) says
Heat can kill bacteria and viruses, but toxins are chemical and–unless there is a chemical reaction associated with other ingredients–are not changed by heat.
Rachel G says
This is very good to know! I’ve heard different reports on the safety/non-safety of green potatoes. I need to do a better job of storing mine!
Debra says
I cooked some green potatoes for Thanksgiving dinner one year, unaware of the danger. Four family members became violently ill. There was only a few green spots here and there. Never again. If I see green, I toss it.
Frances Liz Fernandez says
Aha! I broke every potato storing rule too. Now i know why. Thanks.
Noreen says
I got violently ill and was rushed to hospital after eating some potato bake, not sure if the half-a-glass red wine may have helped trigger it but it started with itching then all my glands swelled and lots of hurling – doctor gave me adrenaline – i think he thought i was intoxicated – was an awful feeling.
Barbara Garter says
Thanks Carolyn: as a former Professional Food Scientist now part time cruiser, I really appreciate the good information you share here. You are right about the green in the potatoes and the other info you included. Thanks again!
The Boat Galley says
Thanks!
Lupari Sue says
We use the supermarket bags that you take so you dont use plastic. Kept in a cool dry place. . Apparently scrubbed potatoes still with dirt on last longer than washed ones too. I didnt know about onions and potatoes. Will separate them in future. Thanks Carolyn for your informative articles
Hannah Gardner says
I have heard that women who are pregnant or could be pregnant should be very careful not to eat green potatoes. The rest of us? Have at it.
Ryan says
Oh no! I know this is super delayed, but basically, I have a HUGE phobia of nausea/vomiting. I consumed maybe one or two fingerling potatoes that were green today, but that was it- think I will be safe? The story someone commented above of the four family members getting violently ill freaked me out!
Carolyn Shearlock says
I’m betting you’re going to be just fine as long as you don’t freak.
Ryan says
Okay… Thanks! I hope so! I’m assuming since everywhere I’ve read said it had to be a decent amount to make people sick that I’ll be okay- hopefully! Either way, learned my lesson- hopefully not the hard way!
Nick says
People are usually exaggerating, it seriously takes alot of of it to poison you so she might of just been a bad cook. Lol
MARTHA FOUST says
i was trying to ask if the dark spots on a peeled potato was bad for you i never got to that sight at all.
so if you have a peeled potato and it has black spots on it should we leave them on and cook them like that,
i am just asking because i have a friend that leaves them on, my self i cut them off?
Carolyn Shearlock says
Cut them off.
Hamish Ramsay says
Okay, I’m going to wade in here with completely anecdotal evidence as a reckless scientist who ought to know better than to experiment on myself. Yet I did, having reviewed the literature.
The worst thing that I myself have experienced after deliberately ingesting substantial quantities of severely green potatoes, night after night, was a small amount of stomach discomfort, followed by loose bowel movements.
Thus far. I keep upping the dose, when opportunity presents.
Having said that, I make no guarantee for others – but tiny green tinges probably won’t harm you in the least! Don’t sue me if you die, though. On your own head be it.
Debra Oatman says
I didn’t know eating green potatoes was bad. I found out after Thanksgiving dinner when everyone ended up tossing their cookies all night. Never again!
VIcki Telesford says
My father always told us that green potatoes were OK in small quantities by NOT if you are pregnant. I have always borne that in mind. Not sure of the science but worth mentioning.
anonymous says
Blessings.
PJ says
After living on board and cruising for a total of 32yrs., the best solution we have found is to store potatoes, and onions, separately in good old brown paper bags. Yes by all means leave any dirt on them until ready to use. Have never had an issue.. Just pick your veggies carefully. I always buy loose, never anything that’s been bagged ahead even at the local fruit and veggie stands.
PQ says
Really? I work at a small supermarket and what my superior always does is grab one or two of the cheapest bags of potatoes, opens them and throws them into the “pick your own” box… so at the very least, don’t pick the loose ones in supermarkets either.
BARBARA LOWELL says
I have found that organic potatoes are often sold with a fair amount of green, and that’s an even more expensive throwaway. Look through the bag carefully or buy loose potatoes. Heavy pesticides in potatoes to deter various worms and nematodes also can make you ill. Store in brown bags and use a peeler or fingernail to remove eyes. Discard areas with even a green tinge. Keep out of light. I grow my own so easy in pots and very pretty, but I am not a boat owner.
Maurn says
I’m guessing the violently I’ll reactions, especially after Thanksgiving dinner has more to do with some contaminated meat or egg dish than any green on potatoes. It would take a lot more than a little green potato skin. I eat those all the time if not peeling for the dish preparation. No problems.
V6nce says
Isn’t it all common sense? A potatoe comes out of the ground with a smooth tight skin and a firm white texture.
When it no longer resembles something fresh out of the ground it’s not going to be as good for you or possibly is going to be bad for you, this applies to all fruit and veg
Buy fresh store well and eat quickly or use tinned
Carolyn Shearlock says
Actually, you can store many foods for quite some time and still have them be food.
Sylvia Scott says
I grew up w the understanding that guys in particular shouldn’t eat green potatoes because they could cause sterility. My husband knew that, too. I can’t find a single thing out in cyber space referring to this, nor anything in all my books. Are we both crazy? Maybe just an old wives’ tale? Would love to hear from anyone who might know where this idea came from.
Carolyn Shearlock says
Never heard that, so I can’t comment on where it may have come from.
Susan August says
It sounds like I need to keep the onions and potatoes separate? My mom always kept them under the kitchen sink. I’ll have to store them in my laundry room!!
Carolyn Shearlock says
Yes, keep them separate!
Susan August says
Thank you.
Shawn says
Be careful. I’m a 45yr old live aboard and low light will deceive you. A baked potatoe made me sick for days. What i vomited the next day was green potatoe skins. Bad dreams, confusion, itchy, horrible stomach issues. I’ll never eat a baked russet potatoe again. Non green Yukon golds seems fine.