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potatoes turning green

Posted by strawberryjohnjohn (My Page) on
Fri, Jul 25, 08 at 9:38

here in hamburg, michigan i am ready to harvest my two 150 foot rows of potatoes. one row is pontac reds and the other is white russet. two days ago i pulled two plants of each to check the potates. i washed them and stored them in a dark cabinet in the kitchen. today i went to use some for dinner and found they all started to turn green. before i harvest the rest of them i need to know how to stop them from turning green and the best way to store them for a while. thanks JOHN

Follow-Up Postings:

RE: potatoes turning green

I dont grow potatoes..yet. But I had read that this happens when exposed to sunlight too early.
I'm sure someone more experienced with this will chime in.

RE: potatoes turning green

the potatoes i picked did not see sunlight. i picked them on a real cloudy day and they went right in the house to get washed. JOHN

RE: potatoes turning green

The potatoes weren't buried under enough soil, which allowed sunlight to reach them and caused choryphyl production. Green potatoes should not be eaten, they are poisonous. One green potato won't kill you, but eaten in quantity they will make you sick.

You can heap more soil around growing potato plants from time to time, to keep your crop from seeing the light of day. As the potato crop grows, the potatoes come closer to the soil's surface. That is why you want to keep building up the soil. Some folks use tires to surround potato plants, adding another tire as the plant grows.

I don't know how one goes about keeping a quantity of potatoes in storage, except that the storage place should be cool and dark. When I was a kid, we had a potato bin in the kitchen, kind of like a large bread box. You might try doing a search on potato bins to see if they are still available for purchase.


RE: potatoes turning green

lorna, after i washed the potatoes they were not green at all. the next day when i went to use them for dinner is when i noticed the green on them. i always hill the plants as i weed. most of these potatoes were a foot wnder the soil line. JOHN

RE: potatoes turning green

This is from Wikipedia:
"Potatoes contain glycoalkaloids, toxic compounds, of which the most prevalent are solanine and chaconine. Cooking at high temperatures (over 170 C or 340 F) partly destroys these. The concentration of glycoalkaloid in wild potatoes suffices to produce toxic effects in humans. Glycoalkaloids occur in the greatest concentrations just underneath the skin of the tuber, and they increase with age and exposure to light. Glycoalkaloids may cause headaches, diarrhea, cramps and in severe cases coma and death; however, poisoning from potatoes occurs very rarely. Light exposure also causes greening, thus giving a visual clue as to areas of the tuber that may have become more toxic; however, this does not provide a definitive guide, as greening and glycoalkaloid accumulation can occur independently of each other. Some varieties of potato contain greater glycoalkaloid concentrations than others; breeders developing new varieties test for this, and sometimes have to discard an otherwise promising cultivar.

Breeders try to keep solanine levels below 200 mg/kg (200 ppmw). However, when these commercial varieties turn green, even they can approach concentrations of solanine of 1000 mg/kg (1000 ppmw). In normal potatoes, however, analysis has shown solanine levels may be as little as 3.5% of the breeders' maximum, with 7187 mg/kg being found.[21] The National Toxicology Program suggests that the average American consumes at most 12.5 mg/day of solanine from potatoes (note that the toxic dose is actually several times this, depending on body weight). Dr. Douglas L. Holt, the State Extension Specialist for Food Safety at the University of Missouri, notes that no reported cases of potato-source solanine poisoning have occurred in the U.S. in the last 50 years and most cases involved eating green potatoes or drinking potato-leaf tea.

Solanine is also found in other plants, mainly in the mostly-deadly nightshade family, which includes a minority of edible plants including the potato and the tomato, and other typically more dangerous plants like tobacco. This poison affects the nervous system causing weakness and confusion."

RE: potatoes turning green

Hey John,

Sorry to hear about your potatoes. I've never heard of such a thing. I've grown Red Pontiac in the past but never had the trouble you're having. I've never grown white russet. Is it cool in your house? I've never heard of such a thing, but maybe they'll go green just by being too warm. Are they green just on the skin or does it go deep into the flesh? If I get a green one(always from sunlight exposure for me), I'll just peel until all the green is gone.

The best way I store them is in the ground until it starts to get cold. 4 inches of soil on top should protect them from sunlight. I will warn you that critters will ganw on them a little, but those spots scab over and the damage is never great. I then put them in my basement in a root cellar. Dunno if you grew them all for yourself or for sale. You could dig 'em as you sell 'em.

Good luck solving the mystery. I'd like to hear a follow-up on how you solve this. Potatoes are one of my favorite crops.

RE: potatoes turning green

I don't remember grandpa washing them. Seems he just knocked off the dirt and stored them in a cool dark place. Might want to try that.

RE: potatoes turning green

I've never washed potatoes to be stored, either. It's usually not recommended, because of their increased chance for premature rotting if not totally dry when they are stored. It shouldn't have anything to do with turning green, however.

Today's basements aren't 'cellars' anymore. They're light and airy and heated. sigh. My husband had radiators installed in my 200year old basement I used to use for a root cellar, and it isn't anymore. LOL

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