What Forms Purple Potatoes? Planting Methods and Harvest Time

Purple potatoes, also known as Peruvian purple potatoes, have naturally purple or deep blue skin and flesh, and contain exceptionally high levels of antioxidants, which makes them very healthy. Their distinctive color comes from natural anthocyanin pigments; some Peruvian potatoes are naturally purple, while others have been bred for a deeper hue.

They come in different shapes, textures and sizes; some of them are small or fingerling types, while others can be harvested small as new potatoes or grown to large baking size. There is a lot of variation between each variety, and purple potatoes can taste similar to any other potato - their color does not produce any special flavor. Some varieties lose some of their pigment when boiled, but retain their color when fried, roasted, baked or mashed.

Purple Potato Varieties
The Purple Peruvian is purple all the way through and produces well late in the season. Purple Fiesta is a mid-season specialty potato that keeps its color when cooked. Purple Viking has a true purple skin with splashes of pinkish red, snow-white flesh, and becomes sweeter during storage. Purple Majesty is perhaps the most intensely dark purple variety. Purple Petite Pelisse is a fingerling potato that has been developed to produce a deep purple color.

Because the deep blue and purple shades differ only slightly, many of the best purple potatoes have blue in their names. The most common of these is Adirondack Blue, which is large and oval with deep blue skin and slightly purple flesh. Unlike some others, it keeps its color when boiled.

All Blue potatoes, also known as Russian Blue, Blue Marker, Congo and several other names, is a heritage potato with deep purple characteristics and purple flesh with white streaks. Midnight Moon has near-purple skin and moist golden-yellow flesh.

Growing Purple Potatoes
Grown like other potatoes, purple strains are original South American strains that usually thrive under harsh conditions and are often resistant to disease. Potatoes need seven or eight hours of sunlight, well-drained moist soil, and good fertility. Apply an all-purpose fertilizer at planting time and apply more when the plants are about half grown. Plant potatoes in cool weather, when there is no danger of freezing but while temperatures remain below the mid-80s, which reduces tuber formation.

Look online for “seed” potatoes, but order early while supplies last. Before planting, cut the seed potatoes into small pieces, each with one or two small “eyes” or leaf buds. Plant them about 3 inches deep and 1 foot apart in rows, hills, raised beds or containers.

Potato tubers sprout from short stolons on the lower stems of the leafy plant, but they must be kept in complete darkness to avoid greening in the sun, or a toxic plant alkaloid called solanine. Prevent this by piling soil or a thick layer of mulch around the seedlings, repeating as needed until the lower six or eight inches of stem are buried.

Harvesting Potatoes
Small or “new” purple potatoes can be harvested about three months after planting, but for larger mature tubers, wait until the plants turn yellow, or about 4 months after planting, cut down the mature plants and then dig up the tubers. Dig gently to avoid cuts and bruises; do not wash them, just brush off the soil.

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