Will green potatoes kill you?

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From the Aug 1988 issue of National Gardening, answer to a question:

The green on your potatoes is actually chlorophyll. a sign that the potatoes were exposed to light. Chlorophyll isn't harmful but it means solanine, the same toxic substance that's in tomato, pepper and eggplant leaves, is present. A small amount of solanine occurs naturally in potatoes and helps give them their distinctive flavor. But when a potato is bruised, exposed to light or has begin to sprout, additional amounts of solanine are produced, concentrated mainly in the potatoes' skin and eyes. Eating large quantities of solanine can cause headaches, fever and diarrhea, but finding a few green tubers isn't any reason to throw out all your potatoes. You'd have to eat 2-1/2 pounds of peeled, cooked, "green" potatoes or 12 pounds of undamaged potatoes at one sitting to be harmed by the substance.

To avoid having green potatoes, hill them with soil or hay mulch while they're growing so the tubers aren't exposed to light and dry them in a shed or garage. Leaving the potatoes in the sun for a few hours, as you did, shouldn't have any adverse effects on them, though. For any that have turned, simply peel away the green and eat the potatoes as you normally would.

-- Old Git (anon@spamproblems.com), April 24, 1999


However, the green color isn't at all harmful to their use as "seed potatoes", so if you save potatoes for seed and find some green ones, dedicate those to seed if they look o.k. otherwise.

-- anita (hillsidefarm@drbs.com), April 24, 1999.

Speaking of potatoes...

My neighbor is an expert gardener, and he has helped us start an easy way to grow potatoes in a compost bin. Throw in the organic matter, the peat moss, the dirt, etc., and the potato seedlings.

They take root right there and produce pounds and pounds of potatoes. He's been doing this for a long time. It is nearly effortless, once the bin is filled.

-- Sara Nealy (keithn@aloha.net), April 24, 1999.

From various web pages, keying on solanine:

Solanine present in potato (Solanum tuberosum) - most of plant except tubers is poisonous. Tuber contains solanine too, but toxic dose is about 100 potatoes. Green potatoes (which turn green after exposure to sunlight) can cause fatal poisonings. Green and damaged potatoes are even more toxic.

Reported signs and symptoms of solanine toxicity include dilated pupils, salivation (drooling), nausea (upset stomach), vomiting, headache, bloating, diarrhea, respiratory depression (i.e., breathing slows down), central nervous system depression, confusion, tachycardia (excessively rapid heart beat), coma and death.

The major toxin [in nightshades] is solanine, an alkaloidal glycoside, and along with other glycosides and atropine have numerous and powerful effects on the body. ... Other Solanum species contain the same poisonous principle. These include buffalobur (Solanum cornutum), the ornamental Jerusalem cherry (Solanum pseudocapsicum), and the common white potato (Solanum tuberosum). Sprouts and sunburned (green) or spoiled potato tubers should not be mixed in feed because they also contain solanine.

Vines of tomatoes (Lycopersicon esculentum, nightshade family) contain similar glycoalkaloids. Toxicity is also related to that seen with Jimsonweed. Interesting trivia also found: a single oleander leaf, if eaten, can kill an adult human; 2 wisteria seed, if eaten, can kill a child.

-- Tom Carey (tomcarey@mindspring.com), April 25, 1999.

Tom, thanks for that. Some seed catalogues will state that some seeds/plants are toxic, but Thompson & Morgan has red-letetred warnings in their catalogue descriptions on ANY seed they carry which is known to cause illness, allergy or death, and in what form (flower, leaf, fruit, seed, and so on). For instance, the currently popular foxglove is where we get digitalis and it's poisonous.

The oleander you mention--if burned the smoke is also poisonous (same for poison ivy, can get in your nose and throat and suffocate you from swellings). Hell, maybe we should ban wisteria. . .

-- Old Git (anon@spamproblems.com), April 25, 1999.

What about growing tomatoes on an old compost pile? I have had one for ten years (used it in the garden a lot) but it is pretty high and I was thinking about growing tomatoes there. Will they do ok?

-- Cherri (sams@brigadoon.com), April 25, 1999.

Why not transplant the tomato seedling from the compost pile?

-- Donna (moment@pacbell.net), April 25, 1999.

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