Potato

The potato (Solanum tuberosum) is a cool-season, tuber-forming member of the nightshade family (Solanaceae) grown around the world as a staple food crop, alongside wheat and rice.¹³⁴ It is native to South America, specifically the Andean and Chilean regions, with a range taking in parts of Argentina, Bolivia, Chile, Peru, Colombia, Ecuador, and Venezuela; the modern cultivated plant traces back to Andean and Chilean landraces developed by pre-Columbian farmers.¹²³⁴ For the homesteader, its appeal is hard to beat: a single planting of seed tubers in cool spring soil yields a dense, storable crop of calories from a small footprint, and the cues for when to dig are read straight off the plant rather than the calendar.

Botanically it is a herbaceous perennial, though it is almost always grown as an annual.¹³⁴ Plants stand roughly 0.4 to 1.4 metres tall and range from erect to sprawling depending on cultivar and conditions.³ The stems are soft and green, and it is the underground stems, called stolons, that swell at their tips into the edible tubers.¹³ The leaves are compound, with several ovate leaflets ranged along a central rachis, giving the typical “nightshade” look; this foliage is entirely inedible because of toxic alkaloids.¹ Flowers are usually inconspicuous in cultivated settings and vary in colour by variety, from white to pink, and are followed by small green berry-like fruits that resemble miniature green tomatoes and are highly poisonous.¹³⁴ The tuber itself varies in skin and flesh colour, from white and yellow to red, but any green tinge to the skin signals a build-up of glycoalkaloids, and those green portions should not be eaten.¹⁴

Growing potato

Potato is propagated from “seed potatoes” — tuber pieces each carrying at least one “eye” — rather than from true botanical seed.⁴ In spring, plant seed potatoes 2 to 3 inches deep and 12 inches apart in rows spaced 2½ to 3 feet apart.⁴ Because the crop tolerates cool soil, it can go in as soon as the ground is workable, about 2 to 3 weeks before the average last frost; it is described as a cool-season vegetable that handles cool soil and moderate frost.⁴ As a garden crop it is listed as hardy across a wide span, USDA zones 2 to 11.⁴

Give potatoes full sun.¹⁴ They grow best in fertile, well-drained, sandy soil, and acid soil is actually preferred because it reduces the likelihood of scab disease.¹⁴ Water regularly and thoroughly through the growing season; consistent moisture matters, while waterlogging predisposes the tubers to rot.⁴ Once the plants reach about 12 inches tall, hill soil, straw, or compost up around the stems to build a mound 6 to 8 inches high.⁴ Hilling keeps the developing tubers covered from sunlight, which is what prevents them greening and forming solanine.⁴

Harvest and uses

Rather than counting days, the potato tells you when it is ready through its growth stages.⁴ Dig “early” potatoes when the tops begin to flower, for tender new potatoes used straight away.⁴ For the full-maturity main crop, wait until the tops die down before lifting, which gives firmer tubers better suited to storage.⁴

Only the properly stored, non-green tubers are eaten.¹⁴ They are the swollen tips of the underground stolons and form the entire edible yield of the plant, since every other part is toxic.¹³ Worldwide the potato is one of the great staple crops, ranking with wheat and rice, which is precisely what makes it such a reliable anchor for a homestead food plot: a high-calorie, storable harvest from a single season’s planting.²³⁴

Safety and cautions

The potato is a nightshade, and only the properly stored, non-green tubers are safe to eat.¹⁴ All green tissues are poisonous because of glycoalkaloids such as solanine, including greened tuber skin, sprouts, leaves, stems, and the berries.¹⁴ A few grounded points for any grower:

• The small green berry-like fruits that follow the flowers are highly poisonous and must not be eaten, despite resembling tiny green tomatoes.¹
• The foliage — leaves and stems — is entirely inedible due to its toxic alkaloids.¹
• Any green coloration on a tuber’s skin indicates glycoalkaloid accumulation; cut away and discard affected portions, and do not eat heavily greened tubers.¹⁴
• This is why hilling matters in the garden: keeping the tubers buried and out of sunlight prevents the greening and solanine formation in the first place.⁴

Stored correctly in the dark, cured tubers from a healthy plant are a safe, nutritious staple; the toxicity sits in the green tissue and in tubers exposed to light, so the safe practice is simple — keep them covered while growing and keep them dark in storage.¹⁴

Sources

1. Solanum tuberosum (Potato) – NC State Extension Plant Toolbox
2. The Biology of Solanum tuberosum (L.) (Potatoes) – Canadian Food Inspection Agency
3. Solanum tuberosum – Solanaceae Source (Natural History Museum)
4. Solanum tuberosum – Missouri Botanical Garden Plant Finder