Potato

Potatoes grow best in full sun and well-drained, sandy, acidic soil; poor drainage can rot tubers, while acidic soil helps prevent bacterial scab. They are usually started from seed potatoes cut so each piece carries at least two eyes, left to scab over for a day before planting eyes-up about 5 to 6 inches apart. As the plants grow, soil or mulch is hilled up around the base once they reach a foot tall and again once or twice more through the season, encouraging more tubers to form along the buried stem; tubers left exposed to light will turn green and develop toxic compounds. The crop tolerates a bit of frost, so planting can begin while cool weather still lingers.

Colorado potato beetles are a recurring threat, laying yellow egg masses whose larvae defoliate the foliage, alongside flea beetles, wireworms and leafhoppers. Potato late blight can rot tubers outright and render them inedible, and the crop is also vulnerable to various viral, bacterial and fungal diseases; affected plants are best removed and destroyed rather than left in the ground. Starting with certified disease-free seed potatoes, rotating crops and keeping garden tools clean all help hold these problems in check.

Potatoes can be dug as tender "new" potatoes once the plants begin to flower, about 7 to 8 weeks after planting, when the skins are still thin and delicate. Left to mature fully, the crop takes 3 to 4 months and is typically lifted once the tubers are fully grown or the foliage has dried down.

Potatoes are grown chiefly for their starchy underground tubers and rank among the world's most important food crops, with thousands of cultivars offering a range of textures, sizes and colors suited to different culinary uses. Only the tuber itself is eaten; the green parts of the plant, along with sprouts and any greened skin, contain the toxin solanine and are not food.

The potato is native to South America, in the region spanning parts of Argentina, Bolivia, Chile and Peru. From this center it spread to become a widely cultivated crop, with present-day production led by countries including China, Germany, India, Russia and the United States.