No info about growing them, but here's some interesting stuff about yams/sweet potatoes from America's Test Kitchen/Cooks Illustrated (
http://www.americastestkitchen.com):
"TASTING LAB: Sweet Potatoes
In this country, the terms "yam" and "sweet potato" have become
interchangable, both referring to the orange-skinned, orange-fleshed,
and sweet-tasting root vegetable traditionally found next to the
potatoes in the supermarket. But there is a world of sweet potatoes
that extends far beyond these confines. We wondered just how deep
the differences in sweet potatoes ran, so we gathered seven varieties
to taste. We tried three traditional varieties (traditional at least
to those of us raised in the United States and Europe)--Beauregard,
Jewel, and Red Garnet--and four nontraditional--Japanese White, White
Sweet, Batata, and Okinawa. In the traditional category, the
Beauregard (usually sold as a conventional sweet potato) was favored
for its "standard sweet potato" flavor and "basic, all-around good"
quality. Of the nontraditional varieties, the Japanese White was the
hands-down winner, praised for its "heavy chestnut flavor" and
"velvety" texture.
RECIPE: Sweet Potato Chips
From: Restaurant Favorites, October 2003
Serves 6
These chips can be served with any fish or meat entrée or on their
own as a snack. It is important to cut the sweet potatoes 1/16 inch
thick, a task easily done by a mandoline. If you don't have a
mandoline, the slicing blade of a food processor will suffice
(although the chips will not be cut to precisely the right
thickness, so you may need to increase the cooking time to ensure
crisp chips). Because the oil will bubble up when you add the
chips, be sure you have at least 3 inches of room at the top
of the pot.
2 quarts canola oil
4 large sweet potatoes (about 3 pounds), peeled and cut into
1/16-inch-thick slices
Salt
Confectioners' sugar
1. Heat the canola oil in a Dutch oven over medium heat until it
reaches 375 degrees. (Use an instant-read thermometer that registers
high temperatures or clip a candy/deep-fat thermometer onto the side
of the pan before turning on the heat.) Carefully add one sixth of
the sweet potatoes and fry until lightly browned, 2 1/2 to 3 minutes,
adjusting the heat as necessary to maintain the cooking temperature.
Using a slotted spoon or spider, transfer the sweet potato chips to
a rimmed baking sheet lined with several layers of paper towels and
sprinkle them lightly with salt. Fry the remaining batches of sweet
potatoes, letting the oil come back to 375 degrees after each batch,
adding them to the baking sheet and salting them.
2. Let the sweet potato chips cool completely. Dust with
confectioners' sugar and serve."