Why Sweet Potatoes Aren't Yams

POUND RIDGE, N.Y. (AP) â€” One thing about sweet potatoes: Purists don't call them yams, terming it a widespread misnomer. Another thing: They're very good for you. And third: Certain varieties

Wednesday, May 3rd 2000, 12:00 am

By: News On 6

POUND RIDGE, N.Y. (AP) â€” One thing about sweet potatoes: Purists don't call them yams, terming it a widespread misnomer. Another thing: They're very good for you. And third: Certain varieties grow easily in the North.

Of different botanical families, sweet potatoes originated in tropical Peru and Ecuador while true yams, less nutritious, came from Africa and can't be raised in the United States because our growing season is not long enough. They're imported from the Caribbean.

The confusion in names reputedly traces back to an adman who coined ``Louisiana yams'' 50 years ago to make sweet potatoes grown in that state sound attractively different.

But, seen side by side, they don't even look alike, the sweet potatoes generally having smooth skin and orange color while the yams are brown and scaly. One claim to fame of the yam is that birth control pills are derived from it.

Nutritionally, sweet potatoes are rich in beta carotene providing the Vitamin A that is good for vision, among other things. Yams are low in it.

Years ago, sweet potatoes were deemed a Southern vegetable ungrowable in northern gardens because of frosts. But then varieties were bred that could make it in the North. Development of black plastic mulch and row covers helped warm the soil and speed the growing process.

Georgia Jet, maturing in 90 days with high yields, is a variety much recommended for Northern growing. Its flesh is moist and deep orange. The variety is offered at $9.95 for 25 plants by Park Seed, 1 Parkton Ave., Greenwood, S.C., 29647-0001, Tel. 800-845-3369, www.parkseed.com. They're shipped bareroot at the right planting time for the customer's climate.

Another 90-day plant grown in northern areas is Louisiana-developed Centennial, also offered by Park at the same price.

The plants are actually tall sprouts grown from the previous year's crop of sweet potatoes. They're also called slips or draws.

Some veteran gardeners grow their own slips, but if you're new to raising this vegetable, or pressed for time, the easiest and fastest route is to order the plants from a supplier.

After the planting site is softened by tilling to a depth of at least eight inches, pile the soil up in a series of ridges about eight inches high and a foot wide to give the roots plenty of room in which to grow. You space the plants in these ridges about a foot and a half apart and deep enough to cover the roots up to the first leaves.

You should water first with a high-phosphorous starter solution and then plentifully for a few days. Southern varieties take four frost-free months to mature.

In the North, as noted, you have about three months without frost, starting from when the ground is warm enough, which means late May in my area of southern New York.

To harvest, you dig the roots up carefully. Harvest time in the South and central states runs from late September to the middle of October. In the North, do it before you hear frost warnings.

If you have a successful harvest and want to try growing your own slips the following year, store some of the best looking of your potatoes in a warm, well-lit area. (If you don't have your own potatoes to work with, you can look in the supermarket in late fall for some nice candidates to store away.)

They'll likely have begun to sprout at one end about the time you're ready to pot them next year. That's about 90 days before your first frost-free date. Put them in containers filled with soil, with the sprouting end kept above the soil surface. In three months, if everything goes well, you should have slips good enough to plant in the garden.

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EDITOR'S NOTE: George Bria retired from the AP in 1981 after 40 years that included coverage of World War II from Italy.