Chances are you sprouted sweet potatoes yourself as a kid. That's because--in theory at least--they're fast-growing and not hard to get started. We had to wait a month for our first sweet potatoes to sprout, but our patience was finally rewarded with two vividly moldering tubers. A friend offered an explanation: sweet potatoes are routinely sprayed with a chemical that inhibits sprouting--a boon to shippers and grocers but a nuisance to kitchen gardeners. We began again, this time with tubers that had already started to sprout, and we had no trouble producing lush, vinelike plants in a matter of weeks. Homegrown sweet potatoes or ones from a local source, I imagine, would also work.

MATERIALS:
Look for a sweet potato that has already started to sprout, even if the sprouts are no longer fresh. This signals that the tuber has either escaped the spraying process or possesses the right genetic stuff to circumvent it. You'll also need a glass jar and several wooden toothpicks, plus potting mix and a terra-cotta flowerpot for eventual transplanting (choose a size that accommodates your tuber with a little room left over).

PLANTING TECHNIQUE:
Pierce the middle of the sweet potato with two toothpicks, one on each side, and suspend it over the jar. Fill the jar almost to the top with lukewarm water and set it on a bright windowsill. Make sure that the pointier, root end of the potato faces downward. We inadvertently planted one of our sweet potatoes upside down, and although it eventually sprouted, it seemed a little befuddled, taking several weeks longer than its companions to send out roots.

DAYS TO SPROUTING:
Seven to 14. The first thing you'll notice are little whiskery rootlets growing under the water. Be patient: in a week or two you should see some tiny red sprouts at the top, which will soon open into small red-veined green leaves. Then watch out! Your sweet potato will turn into a growing machine, churning out masses of ivylike foliage at a prodigious rate.

LONG-TERM CARE:
When growth is about 6 to 8 inches high, it's time to transplant to a more permanent container. Fill the flowerpot about a third of the way up with potting mix, then place the tuber on top of the mix and fill in around it. If at all possible, cover the tuber completely with mix to discourage rotting. Water often enough to keep the mix lightly moist.