There are more glamorous crops, but nothing in the vegetable garden is more rewarding than the lowly potato. Fresh-dug, organic, homegrown potatoes are dense, creamy, so flavorful as to need very little duding up. Conventionally grown potatoes, on the other hand, are so pumped up with artificial fertilizers and sprayed with such powerful chemicals–as Michael Pollan pointed out in a great piece in the New York Times Magazine eleven years ago–that they taste entirely too weird to eat.
Potatoes also deliver a huge amount of food for the land you devote to them. As a crop, they are so tough, they do equally well planted in April or July. You can steal little potatoes out of the ground early, before the whole clump is ready for harvest. And with some varieties fully grown in just two months, they are very useful for the seasonal orchestration that you have to have in a small garden.
So it's welcome news this week from New York Times that Cornell University is breeding new varieties particularly for my part of the world that may do better than the old standards. They have a Yukon Gold replacement, Keuka Gold, that I will try next year, since I do Yukon Golds every year, even though they are not particularly productive in my garden. Why do I plant them? Because life is short and they are simply the most delicious variety of all, with their butter-colored flesh and thin skins. To find that flavor in a potato that produces more than a couple of spuds per plant…well, it's a potato obsessive's dream. My other favorites are All Blue, a flaky, dense potato that is excellent for baking, roasting, and mashing, and Sangre, a big productive storage variety.
Of course, all this potato celebration is wistful this year, since my second crop of potatoes, the big crop that I plant in mid-summer for storage, was entirely withered by late blight. Only a few of the seed potatoes I planted survived long enough to send up a leaf, and then the leaf instantly blackened as if someone had burned it.
Peculiarly enough, the Times potato story doesn't mention this regional tragedy–maybe because the piece ran in the "Dining" section, and no one wanted to put the readers off their food. However, this piece from The Cornell Chronicle shows how widespread late blight was in New York State even by July 10.
Why haven't we made much progress against this pest, a water mold called Phytophthora infestans, since the Irish potato famine of the 1840's?
This excellent article in New Scientist explains why it's so difficult to breed resistance into potatoes. Their genetics are super-complicated, making trying out new crosses an unwieldy process. (Unfortunately, you have to subscribe to New Scientist in order to access this link, something I highly recommend. Very informative, very fun.)
At the same time, the genome for the late blight pest, which was sequenced this year, is also a diabolically complicated piece of work. A recent piece in Nature News, which includes an interview with Chad Nusbaum of the Broad Institute, one of the project's scientists, does a particularly good job of describing the lethal overkill that causes late blight:
When comparing P. infestans with similar
organisms in the same genus, stretches of the genome stood out as being
highly variable, unusually large and full of transposons — sequences
that make copies of themselves and jump around in the genome. The
researchers believe that the transposons, which make up about 74% of
this unusually unwieldy genome, code for the blight's 'weapons' against
"That is an insane number. For microbes, 25% is a lot," says Nusbaum.
So, there is not just an AK-47 in the house, but also a sharp ax, a bayonet, a
bow and arrow, and a rocket-launcher. And these weapons replicate their own parts and lend them to each other, too, allowing the mold to evolve new ways of killing
potatoes nearly as soon as a potato develops a new way of resisting it. Commercial growers control this problem with loads of fungicides, and according to New Scientist are constantly having to add more. Organic farmers use copper-based sprays.
I use nothing. Ever since my first experience almost 20 years ago as a beginning gardener, sprinkling rotenone onto my roses to get rid of Japanese beetles–the beetles didn't mind, the roses did–I've never used any pesticide in my garden. By now, I feel that anything that needs to be shaken out of a can or sprayed is antithetical to a healthy garden and a healthy mindset about gardening.
Next season, I'm sure to go naked and just move the potatoes to another section of the garden. But if I lose most of them again, it's possible that the gardener, too, will evolve.