Potato

Solanum tuberosum was domesticated in the Andes Mountains of South America approximately 7,000 to 10,000 years ago.

• Originated in the region spanning southern Peru, Bolivia, and northern Argentina, near Lake Titicaca
• Domesticated from wild Solanum species (likely S. brevicaule complex) by Andean peoples
• The Inca civilization and their predecessors built their entire agricultural system around the potato
• Inca farmers developed freeze-drying (chuño) — placing potatoes in freezing high-altitude nights, then crushing out the water under the hot daytime sun — creating a shelf-stable product lasting years
• Spanish conquistadors encountered the potato in the 1530s and brought it to Europe around 1570
• Initially met with suspicion in Europe — blamed for leprosy, feared as poisonous, banned in some regions
• Antoine-Augustin Parmentier popularized the potato in France in the 1770s after being fed only potatoes as a Prussian prisoner of war
• Parmentier's strategy of posting guards around potato fields (to make them seem valuable) famously worked — peasants stole and planted them
• The potato revolutionized European agriculture and population growth — more calories per acre than any grain
• Brought to North America by Irish and Scotch-Irish immigrants in the early 1700s
• The genus Solanum contains approximately 1,500 to 2,000 species

Solanum tuberosum is a herbaceous perennial grown as an annual for its tubers.

Plant:
• Erect, spreading, 30 to 100 cm tall
• Green to purplish-green, hairy stems
• Branching from the base

Leaves:
• Compound, pinnate, 10 to 30 cm long
• Divided into 5 to 9 pairs of lateral leaflets plus a terminal leaflet
• Often with smaller interjected leaflets between the major ones
• Green, slightly hairy

Flowers:
• Showy, 2 to 3 cm across
• Five fused petals, white, pink, red, purple, or blue
• Bright yellow stamens forming a central cone
• Self-pollinating but visited by bees

Tubers (the edible storage organ):
• Modified underground stems (not roots) — swollen stem tips (stolons) that store starch
• Shape: round, oval, elongated, or kidney-shaped
• Skin colors: brown, red, yellow, purple, blue, or white
• Flesh: white, cream, yellow, or blue/purple
• Size: 5 to 20 cm long, 50 to 500+ grams
• "Eyes" — dormant buds on the tuber surface, each capable of growing into a new plant

Roots:
• Fibrous, shallow, extending 30 to 60 cm

Berries (poisonous):
• Small, green, tomato-like fruits produced after flowering
• Contain solanine — TOXIC, never eat
• Contain true seeds used only in breeding programs

Potatoes are one of the most nutritionally complete foods.

Per 100 g baked potato (with skin):
• Energy: approximately 93 kcal
• Carbohydrates: 21.2 g (including 2.2 g fiber)
• Protein: 2.5 g
• Fat: 0.1 g
• Vitamin C: 13 mg (22% DV)
• Vitamin B6: 0.313 mg (24% DV)
• Potassium: 535 mg (11% DV) — more potassium per serving than a banana
• Manganese: 0.193 mg
• Phosphorus: 70 mg
• Magnesium: 28 mg
• Folate: 26 mcg

Nutritional highlights:
• Contains all essential amino acids — one of the most protein-complete plant foods
• High-quality protein with a biological value second only to eggs among common foods
• Excellent source of vitamin C (especially when fresh)
• One of the best dietary sources of potassium
• Contains resistant starch (especially when cooked and cooled) — a prebiotic fiber
• The vitamin C content was critical in preventing scurvy in European populations
• Per acre, potatoes produce more protein, vitamin C, and calories than any other major crop

GREEN POTATOES AND ALL GREEN PARTS ARE TOXIC due to glycoalkaloids.

• Solanine and chaconine — glycoalkaloid toxins found in all parts of the potato plant except the tuber flesh
• GREEN SKIN indicates chlorophyll formation AND elevated glycoalkaloid levels — a warning signal
• Glycoalkaloid levels increase when potatoes are exposed to light, damaged, or sprouting
• Symptoms of solanine poisoning: nausea, vomiting, abdominal pain, diarrhea, headache, dizziness, and in severe cases, neurological symptoms, paralysis, and death
• Lethal dose estimated at 2 to 5 mg per kg body weight
• Cooking does NOT significantly reduce glycoalkaloid levels (they are heat-stable)
• NEVER eat green potatoes, potato sprouts, potato leaves, or potato berries
• Always store potatoes in darkness to prevent greening
• Peel away any green areas generously — solanine is concentrated in the skin
• The flowers, leaves, stems, and berries of the potato plant are all poisonous
• Potatoes that taste bitter may have elevated glycoalkaloid levels

Potatoes are cool-season crops typically grown from "seed potatoes."

Seed potatoes:
• NOT true seeds — small tubers or pieces of tuber with at least one "eye" (bud)
• Plant certified disease-free seed potatoes — grocery store potatoes may carry diseases
• Cut larger seed potatoes into pieces, each with 1 to 2 eyes
• Allow cut surfaces to dry and callus for 1 to 2 days before planting

Planting:
• Plant 2 to 4 weeks before last frost date — potatoes tolerate cold soil
• Plant 7 to 15 cm deep, 25 to 35 cm apart in rows 60 to 90 cm apart

Hilling:
• As plants grow, mound soil up around the stems ("hilling") — this:
• Prevents tubers from being exposed to light (which causes greening and solanine production)
• Increases tuber production along the buried stem
• Hill 2 to 3 times during the growing season

Site:
• Full sun
• Loose, well-drained, slightly acidic soil (pH 4.8 to 6.5) — acidic soil reduces scab disease
• Consistent moisture during tuber development

Harvest:
• "New potatoes" — harvest early (60 to 80 days), when skins are thin and easily rubbed off
• Mature potatoes — harvest when vines die back and dry (90 to 120 days)
• Dig carefully with a fork — avoid spearing tubers
• Cure in a dark, well-ventilated area at 13 to 18°C for 1 to 2 weeks to toughen skins
• Store in a COOL (4 to 10°C), DARK, humid location — NEVER refrigerate (converts starch to sugar)
• Properly stored potatoes keep for months

Culinary uses:
• Baked: the simplest and most popular — split and topped with butter, sour cream, chives, cheese, or bacon
• Mashed: boiled and mashed with butter and milk — one of the world's most beloved comfort foods
• French fries — the world's most popular potato preparation
• Potato chips — the best-selling snack food globally
• Boiled: as a side dish, in potato salad, or as part of a meal
• Roasted: cubed and roasted with olive oil and rosemary
• Hash browns, latkes, and potato pancakes
• Gnocchi — Italian potato dumplings
• Vichyssoise — chilled potato-leek soup
• Potato bread, potato pancakes, boxty (Irish)
• Gratin dauphinois — French scalloped potatoes with cream and cheese
• Poutine — Canadian fries with cheese curds and gravy
• Aloo gobi, aloo matar — Indian potato dishes

Industrial uses:
• Potato starch — used in food processing, paper, and textiles
• Vodka — potatoes are a traditional base spirit
• Biodegradable packaging from potato starch
• Potato flour in gluten-free baking