When I first ordered Peruvian Purple seed potatoes, I thought of them more as a curiosity than as a real crop. I was curious about how this native of the Peruvian highlands would adapt to our own high-desert conditions. I was also aware of their very high anthocyanin content, and I’m never one to turn down a good source of antioxidants. I’m still digging them for winter use, and they are one of my most successful crops this year and fill an interesting niche in my household menu: they’re readily available when nearly everything else is dormant.
I planted mine in a strip at the side of my house, which gets very hot in the summer. I did water them but not as much as they might have liked. Even so, they flourished and looked very pretty in their season. Incidentally, this brings up the fact that much gardening information on the Web is clearly written by non-gardeners. Now that edible landscaping is hot, I see recommendations to use the potato as an ornamental, which sounds fine if you don’t know that the vegetative parts die off in late summer and look just awful. So plant them where some other big pretty plant will spill over and fill the empty space in late summer, or put them in an out-of-the-way place where you can admire them in their season and not see them as much when they die back. Do keep them weeded.
When they flowered I scrabbled under themn to look for new potatoes, as I do with all my potatoes, but didn’t find any, and thought they were probably a loss. However, in November when I dug up the space for the winter, I found a treasure trove of earth-amethysts. They were blemish-free and looked very lovely after scrubbing, with deep purple skins that glistened like jewels when wet. I left them in the ground and dug them as I needed them, and on February 1st I’m still digging them and they’re still in perfect condition. They have been completely free of disease and haven’t shown any sprouting yet.
They’re very tasty cut in chunks and roasted in nearly any kind of fat (olive oil and goose fat are probably my favorites) in a 400 degree oven with some coarse salt and a good sprinkling of chopped herbs added near the end of cooking. Chopped garlic added late in the cooking period when it won’t scorch is nice too. A hot potato salad made of chunks of Peruvian Purple boiled in salted water until tender, drained, and dressed with a vinaigrette dressing and a little chopped green onion, parsley, ands celery (plus a good dose of bacon crumbles for non-vegetarians) would be delicious and very decorative. This potato is a survivor, which is probably why it was valued as part of the Peruvian mixed potato patches. It doesn’t demand intensive care and makes do with less water than other potatoes I’ve grown. I recommend it. You can get it at Ronnigers. Formerly I recommended Seed Savers Exchange, and although they don’t have this potato for the 2010 season, I do still recommend them for almost everything else.
Potatoes like our high altitude, but don’t care for our drought and alkaline soil. Even so, they’re easy enough to grow that they spring up all over my gardenwherever they have previously been planted, and I often let them grow where they show up.
Start with good seed stock. Plant enough that you can dig some for new potatoes. Prepare the soil by digging it over, and I like to dig in some vermiculite to lighten the clay and some gypsum to alleviate the alkalinity.
Now plant your potatoes. The tubers grow from the part of the stem that’s underground, so you want as much underground stem as possible. I dig a hole about a foot deep at each planting site, leaving the dirt piled beside the hole. Put the seed potato at the bottom of the hole and cover it with about 6″ of soil. Water, and then wait. When the potato vine has grown up above the level of the ground, fill in the rest of the hole, making sure that some foliage still sticks above the dirt. My garden is very small; if yours is larger, you can dig trenches with a tiller for planting and then use the tiller later in the season to hill them up. Keep them watered moderately throughout the season. Drip irrigation is the most efficient and water-wise way to water them. When they blossom, you can start to dig the ones you intend for new potatoes. When the vines start to die in late summer, don’t worry, they’re supposed to do that. (If they die before late summer, you have a problem.) I have had a little scab here and there on the skins of some of the potatoes, but I just pare it off before cooking. I haven’t seen any other pests or diseases.
The books tell you to buy disease-free seed potatoes every year, but I admit that I just let them come up from the little potatoes I missed when digging, and so far they’ve done fine. Do buy good organic seed stock to start with.
There are lots of elaborate ways to store potatoes, and if you’re interested I recommend Stocking Up as a good general book on food preservation. I just leave mine in the ground and dig as needed. A leaf mulch keeps the ground from freezing, which is important because they become useless if frozen. They start to sprout in February and aren’t good for ccoking once they sprout, but I’ve enjoyed four months of my own “yard potatoes” at that point and am happy enough to turn my culinary attention elsewhere.
BY the way, it’s possible to grow a very useful amount of potatoes in a garbage can. Set it in a sunny place, make drainage holes in the bottom, and put in about a foot of good earth and plant your potatoes. Now, as the vines grow, add more dirt around them, until finally the garbage can is full. Keep them watered, and remember that as the can gets deeper, you need to use more water to wet the whole volume. This method takes advantage of the tendency to form tubers all along the buried stem, although of course you have to have a lot of dirt available. After the first foot, I used composted cotton burrs from the garden center, which are acidic and seemed to benefit the potatoes. Don’t use anything that has manure in it. Harvest them by dumping out the contents of the can in a place where you can use the dirt and picking out the potatoes. I grew a “can” of potatoes last year but lost them because I forgot to dig them in time, and the can, being above the ground, freezes before the ground freezes. So I plan to try it again this year and use those potatoes first. I’ll keep you posted.