© Amédée Masclef · Public domain · Commons
Potato
Caution🐾Kartoffel · (Solanum tuberosum)
Nightshade family (Solanaceae)
Description
The potato is a starchy tuberous vegetable native to the Americas that is consumed as a staple food in many parts of the world. Potatoes are underground stem tubers of the plant Solanum tuberosum, a perennial in the nightshade family Solanaceae.
The potato is one of the world's most important staple foods. The tuber is prepared in countless cooked forms (boiled, steamed, baked, fried) and supplies high-quality carbohydrates, vitamin C, potassium and dietary fibre. Raw potato is not suitable for eating due to indigestible starch and potential solanine exposure. As a side dish, soup, stew or processed into starch and flour, the potato forms the primary caloric source in many countries.
Raw potato juice (pressed from freshly grated tuber, taken on an empty stomach) is used in folk medicine for gastric complaints, heartburn, gastric ulcers and chronic constipation. Contains solanine and indigestible raw starch — use only in small amounts (1–2 tbsp daily), exclusively from greenness-free tubers. Traditional lore without clinical confirmation.
Raw, thinly sliced or grated potato is used in folk medicine as a cooling compress for minor burns (grade I), sunburn and skin irritation. The cool, moist starchy mass is believed to draw out heat and soothe inflammatory reactions. Apply slices directly to the affected area, fix with gauze, change after 20–30 minutes. Not a substitute for medical wound care.
The potato wrap (Kartoffelwickel) is a classic home-remedy application in German folk medicine: boiled potatoes are mashed, wrapped in a cloth and applied warm to the throat (for sore throat), joints (for arthritic pain) or ears (for earache). The moist heat is retained unusually well in the starchy mash (heat capacity comparable to a hot-water bottle). Allow to cool to 40–45 °C before applying to skin — risk of burns!
Potato starch (Amylum solani) is used industrially and in the household as a thickener for sauces, soups and desserts. In naturopathy and traditional housekeeping it is also considered a mild mucous membrane protectant for diarrhoea or stomach upset (water binding in the gut, low-irritant consistency). Traditionally known as a children's remedy — now superseded by oral rehydration solutions.
The potato is an important source of potassium (approx. 420 mg/100 g cooked tuber with skin), supporting blood pressure regulation and cardiac muscle contraction. EFSA and USDA list the potato as a significant contributor to potassium intake in European and North American diets. Cooking with skin retains the highest proportion of potassium; peeling and boiling in excess water reduces potassium content by up to 50 %.
Fresh potatoes contain approximately 13–20 mg of vitamin C per 100 g — a remarkably high value for a starchy food. Historically the potato was an important scurvy-preventing food in Northern Europe and maritime settings. Vitamin C is lost during prolonged cooking and storage; new-season potatoes contain substantially more ascorbic acid than long-stored ones. Cooking in the skin with short cooking times best preserves vitamin C content.
WARNING: Green potato tubers, sprouts and all above-ground plant parts (leaves, berries) contain toxic glycoalkaloids (solanine, chaconine). Consuming green or sprouted potatoes can cause nausea, vomiting, abdominal cramps and, in high doses, neurological symptoms. Cut out green patches generously and deeply; discard heavily sprouted or extensively green tubers — do not cook them. Raw potato is poorly digestible due to indigestible raw starch. Potato juice from greenness-free tubers is considered traditionally safe in small amounts; self-medicating with potato juice for serious gastric complaints does not replace medical evaluation. ASPCA classification (accessed 2026-08-10): toxic to dogs and cats — the toxic parts are the foliage, sprouts and green patches on the tuber, while small amounts of cooked, green-free potato are considered harmless. The ASPCA classifies the whole genus this way.
Cooked potatoes are considered safe in pregnancy and lactation — a valuable source of potassium, vitamin C and carbohydrates. Avoid green or sprouted potatoes (solanine). Raw potato juice should be avoided in pregnancy as a precaution.
Cooked potatoes are fully suitable. Avoid raw potato juice or excessive amounts of raw tuber.
Cooked potatoes (mash, soup, baked) are suitable from weaning age (approx. 6 months) — frequently one of the first solid foods. No green or sprouted potatoes for children; solanine sensitivity may be more pronounced in young children. Potato juice is not suitable for toddlers.
Drug interactions
Kaliumsparende Diuretika / ACE-Hemmer / Kalium-Supplemente
Potatoes are potassium-rich (approx. 420 mg/100 g). With concurrent use of potassium-sparing diuretics (spironolactone, amiloride), ACE inhibitors or potassium supplements, large potato intake may contribute to hyperkalaemia. Relevant only with very high consumption or renal impairment — clinically insignificant at normal dietary levels.
Contraindications
- Green, sprouted or damaged tubers with high solanine content — do not consume.
- Known hypersensitivity to nightshade plants (Solanaceae) — avoid potato.
- Severe renal failure (potassium restriction required) — consult a physician regarding potato consumption.
Harvested part: mature tubers (summer-autumn)
- Time of day:
- Harvest preferably on dry days — wet tubers moulder more quickly in storage. Early varieties from July, mid-season from August, late varieties from September/October.
- Drying:
- HARVEST AND STORAGE: Only harvest tubers after the foliage (haulm) has completely died back or been frosted — the skin is then mature and firm (essential for storage quality). Lift carefully with a garden fork, do not spear. Cure harvested tubers for 1–2 weeks: store at 10–15 °C and high humidity (85–95 %) so that skin wounds suberise. Then store permanently dark, cool (4–8 °C), well-ventilated and dry — light triggers solanine formation! Do not store near apples (ethylene promotes sprouting). Properly stored table potatoes keep 4–6 months.
- Storage:
- 6 months — Dark, cool (4–8 °C), well-ventilated and dry. No light (solanine formation!); keep away from apples and onions. Check regularly; immediately remove any sprouted or green tubers.
- Time of day:
- Early potatoes ('new potatoes') can be tentatively harvested from early/mid-June once flowering begins (trial harvest). First tubers are still small (baby potatoes) at that point but have the highest vitamin C content and delicate flavour.
- Drying:
- Early potatoes are not stored — they have not yet developed a mature, firm skin ('wet skin') and keep for only a few days in the refrigerator. Harvest fresh, consume promptly. Do not wash before refrigerating.
- Storage:
- Early potatoes without storage — harvest fresh and consume within a few days. In the refrigerator max. 3–5 days.
- Stärke (Amylum solani)PolysaccharideContent: 15-25 %Root
Primary constituent of the potato tuber — unbranched amylose (approx. 20–25 %) and branched amylopectin (approx. 75–80 %). Raw starch is indigestible for humans (resistant starch); heating gelatinises the granules and makes them digestible. Cooled cooked potatoes contain more resistant starch (prebiotic, bifidogenic) than freshly cooked.
- Ascorbinsäure (Vitamin C)VitaminContent: 10-30 mg/100 g (frisch)Root
Significant vitamin C source despite starch dominance — new-season potatoes contain up to 30 mg/100 g, long-stored ones only 5–10 mg. Heat- and oxidation-sensitive: boiling peeled in excess water reduces content by 30–50 %. Historically important for scurvy prevention in Northern and Central Europe.
- KaliumMineralContent: 350-550 mg/100 gRoot
The potato is one of the best plant-based potassium sources in the European diet. Potassium is essential for blood pressure regulation, neuromuscular excitation conduction and cardiac function. Cooking with skin retains potassium content largely; peeling and soaking reduces it considerably.
- Vitamin B6 (Pyridoxin)VitaminContent: 0,2-0,3 mg/100 gRoot
A medium potato (approx. 150 g) covers approx. 25–30 % of an adult's daily vitamin B6 requirement. Vitamin B6 is essential for amino acid metabolism, neurotransmitter synthesis (serotonin, dopamine) and immune function. Less heat-sensitive than vitamin C.
- Ballaststoffe (Dietary fibre — Pektin, Zellulose)PolysaccharideContent: 1,5-2,5 %Root
Potatoes with skin provide more dietary fibre than peeled ones. Pectin in the potato skin acts as a soluble fibre (prebiotic, cholesterol-modifying); cellulose as insoluble fibre (promoting intestinal peristalsis). Cooled cooked potatoes additionally contain resistant starch that functions like a dietary fibre.
- Protein (Patatin + Protease-Inhibitoren)OtherContent: 1,5-2,5 %Root
The main storage protein of the potato is patatin (approx. 40 % of total protein) — a glycoprotein with lipase-like activity. Potato protein has relatively high biological value (comparable to legumes) and contains all essential amino acids. Potato protease inhibitors show preclinical appetite-suppressing activity.
- Glykoalkaloide (Solanin / alpha-Solanin, Chaconin / alpha-Chaconin)AlkaloidContent: 0,002-0,1 % (toxisch ab ~0,02 %)Root
Natural defence compounds of the plant against herbivores and pathogens. Concentration in normally stored, light-protected tubers is below the toxicity threshold (< 20 mg/100 g). Significantly elevated in green areas, sprouts, skin and all above-ground plant parts. Solanine and chaconine inhibit cholinesterase (neurotoxic), irritate gastric mucosa and at higher doses can cause vomiting, diarrhoea and confusion. Heat-stable — cooking barely reduces solanine.
- [1]MonographUSDA FoodData Central — Potatoes, flesh and skin, raw (FDC ID 170026)(accessed: 2026-05-21)
- [2]MonographEFSA — Compendium of botanicals reported to contain naturally occurring substances of possible concern for human health when used in food and food supplements (Solanum tuberosum entry)(accessed: 2026-05-21)
- [3]MonographPlants For A Future (PFAF) — Solanum tuberosum database entry(accessed: 2026-05-21)
- [5]MonographHeilkräuter-Lexikon — Kartoffel (Solanum tuberosum)(accessed: 2026-05-21)
- [9]MonographASPCA Animal Poison Control — Deadly Nightshade (Solanum spp)(accessed: 2026-08-10)
- [10]MonographCliniTox Giftpflanzen — Solanum tuberosum L.: stark giftig ++ (Institut für Veterinärpharmakologie und -toxikologie, Universität Zürich)(accessed: 2026-08-10)
- [4]BookGrieve, Maud — A Modern Herbal (1931, Public Domain): Potato entry(accessed: 2026-05-21)
- [6]WikipediaKartoffel (Wikipedia DE)(accessed: 2026-05-21)
- [7]WikipediaPotato (Wikipedia EN)(accessed: 2026-05-21)
- [8]WikidataSolanum tuberosum — Wikidata (Q10998)(accessed: 2026-05-21)
🤝 Permaculture Partners
In your garden, this plant acts as:
✨ Best symbiotic partners
- 🌿 Calendula officinalis Classic companion-planting partner.
- 🌿 Phaseolus vulgaris Bush bean deters Colorado potato beetle (classic rule).
- 🌿 Spinach Spinach as undersowing provides nitrogen and shades soil.
- 🌿 Tagetes patula Marigold deters nematodes that attack potato tubers.
⚠️ Better not planted together
- 🥬 Apium graveolens Classic companion-planting partner.
- 🥬 Cucurbita pepo Both heavy feeders — compete for water and nutrients.
- 🥬 Zucchini Both heavy feeders — water and nutrient competition.
- 🥬 Tomato Both Solanaceae — late blight transfers between them.
Source: Gertrud Franck, Gesunder Garten durch Mischkultur (1980, eigene Kuration) | Helga und Margarete Langerhorst, Mein gesunder Naturgarten (eigene Kuration)