Growing Blue Potatoes

South American blue potatoes, also known as purple potatoes, have naturally blue or purplish skin and flesh, and are unusually high in antioxidants making them superfoods as well as interesting to grow, cook, and serve. They get their color from natural anthocyanin pigments, which are responsible for blues, reds, and violets in many fruits and vegetables. Some varieties are naturally blue, while others are bred by botanists for deeper shades.

They come in different shapes, textures, and sizes; some are small or fingerling varieties, others can be harvested either while small as new potatoes or allowed to grow into large into baking sizes. With a lot of variation, blue potatoes often taste similar to other potatoes - their color does not impart a special flavor. They are cooked the same ways, though some lose a bit of their pigment when boiled, and are better fried, baked, or broiled. 

Blue Potato Varieties

There are at least a couple of dozen different varieties of blue or very similar purple potatoes for sale. One of the most common blues is Adirondack Blue, large and oblong with deep blue skin and purplish flesh. Unlike some others, it keeps its colors when boiled. Vitelotte is a gourmet variety prized for its deep blue skin and violet flesh.

All Blue potato, also known as Russian Blue, Blue Marker, Congo, and several other names, is a heritage potato with a characteristic deep purple skin and a purple flesh streaked with white. Midnight Moon has nearly purple skin and a moist, golden yellow flesh

Growing Blue Potatoes

Grown like other potatoes, many blue varieties, being original South American strains, are exceptionally resistant to diseases and thrive in harsh conditions.

Potatoes need at least seven or eight hours of direct sunshine, well-drained acidic soil, and good fertility, with an all-purpose fertilizer applied at planting time and a little more when the plants are about half grown. Plant potatoes during cool weather when there is no danger of a freeze but when temperatures remain below the mid-80s.

Cut fresh mature “seed” potato tubers into smaller pieces, each with one or two small buds called “eyes” about three inches deep and plant a foot apart in rows, hills, raised beds, or containers. Note: Supermarket potatoes often do poorly because they may not be the best varieties for your area, or may even be treated to prevent sprouting. Get seed potatoes for cutting and planting at local garden centers or online; order early while supplies last.

Potato tubers sprout from short stolons on the lower stems of leafy plants, but must be kept in total darkness to avoid greening in the sun, which can make them taste bitter and lead to a poisonous buildup of the natural alkaloid solanine. As the plants grow, pile soil or thick mulch around the young plants, repeating as needed until six or eight inches of lower stems are buried.

Harvesting Potatoes

Small or “new” blue potatoes can be harvested about three months after planting, but for larger, mature tubers wait until plants turn yellow, or cut the mature plants down about four months after planting and then dig the tubers. Dig gently to avoid damaging thin skins, and do not wash, just brush off dirt.

Store mature tubers in a cool, dry, dark area for up to four or five months, checking regularly for shriveling and decay.