“Most sweet potatoes keep like rocks. You can store them anywhere."

Hold a raw sweet potato in your hand. The potato is rock hard. Its skin has the appearance, if not feel, of old polished wood. As food, the sweet potato looks unpromising.

Pop a sweet potato into your microwave oven. (Believe me, baked is best.) Ten minutes or so later, slice open the cooked potato. The inauspicious skin hides bright orange flesh. All this potato needs is your mouth. No butter, brown sugar, no rum or miniature marshmallows: the baked sweet potato is loveliest naked.

The big man in sweet potatoes in San Diego is Bill Whittman. So I called Mr. Whittman, a man in his late 60s, who told me that he grew up on a cattle ranch on the land that is now Camp Pendleton and that he has been growing sweet potatoes in the San Pasqual Valley near the Wild Animal Park for almost 30 years. “At one time we had as many as 300 acres in sweet potatoes out here, and they all went to a processor.” Whittman quit growing as many potatoes on his 850 acres when the canner in Santa Ana with whom he had a contract went out of business.

Bill Whittman: "We still grow them because we have a lot of history with them"

Photo by Robert Burroughs

Whittman and his son now grow oranges, grapefruit, lemons, Irish potatoes, gladiolus for bulbs, sweet corn, and three or four acres of sweet potatoes. “We grow potatoes now just because we built up a following in the local community, and we grow them to satisfy that. We sell them for 20 cents a pound, sometimes a quarter. But we also still grow them because we have a lot of history with them; and when you know how to do something, you hate to quit doing it, whether it’s riding a horse or growing sweet potatoes or whatever.

“The people we sell them to are by and large people from Southeast San Diego, black people. They are connoisseurs of sweet potatoes. Most of them grew up in the South, and it was part of their diet. They know good sweet potatoes and how to make good sweet potato pie, and they don’t mind making a trip all the way up here from Southeast San Diego to buy ours.

“We grow Golden Pride, a variety you don’t find in the marketplace. It doesn’t store well. It’s very delicate and an exceptionally good eater. On the outside, Golden Pride is tan, about the color of a buff file folder. Inside, they’re bright orange, almost like a carrot, and full of carotene and no strings. It’s a quality product, but with that shortcoming that it won’t keep.

“Most sweet potatoes keep like rocks. You can store them anywhere. But this baby, you need to be very careful how you handle it or you have mush. You need to keep it not too cool and handle it gently.”

Whittman leases his land from the City of San Diego. “So I work for the mayor,” said Whittman, adding, “We’ve been city tenants here since 1964. We’re the city’s largest ag tenant.”

I asked Mr. Whittman how he got into sweet potatoes.

He explained that although his son, in business with him for the past decade, graduated from college, studying business and science, he himself didn’t go to college. “But nowadays,” he says, “there are too many things going on in farming. You need that background.” Mr. Whittman didn’t intend to be a farmer. Growing up, as he did, on the land that is now Camp Pendleton, helping out his father, who was manager of some 300,000 acres that stretched clear up to Orange County, it didn’t occur to him that he would ranch or farm. He went to school in Fallbrook and Oceanside. In high school he worked in a men’s wear shop selling clothes. Then in June of 1950, after the North Koreans crossed the 38th parallel and Truman sent in U.S. troops, Mr. Whittman joined the military. “I spent three years in Korea in the war. Got out of Korea and came back and started farming. My dad by then had a little ranch that he leased with another man, and they needed a ranch foreman, and I didn’t have anything better to do.”

From being a ranch foreman, Mr. Whittman got into farming with a friend. The canner in Santa Ana, for whom Mr. Whittman would end up growing potatoes for almost 20 years, was looking for someone to grow sweet potato. “So my partner and I went to work, and the business just grew up, and here I am.

“I always think about people who have all these plans in their lives. I never had one. I have been like the football guys, I ran for the daylight. I never had a plan. I just did what came next.”

I asked Mr. Whittman how sweet potatoes are grown.

“Well, unlike what most people would think, you don’t take the potato itself out to the field and stick it in the ground.” Sweet potato, Mr. Whittman explained, is a “transplanted crop.” One reason, he said, that North Carolinians have done so well with sweet potato is that they had “all the know-how for sweet potato from growing tobacco,” also a transplanted crop.

“First,” said Mr. Whittman, “we make a seedbed, a place where the potato can sprout. Along in February and March, the potatoes are placed in the seedbed. Then you put domed plastic tents over the beds. Sprouts form off the potato and over the next weeks, those sprouts grow 10, 12 inches of vine. You usually get 6 to 12 sprouts off each potato. The sweet potato is a member of the morning glory family, and the vine looks a lot like morning glory vine.

“Mid-April we start pulling the plants. We take an eight- to ten-inch length of vine out to the field and stick it in the ground, three to four inches deep into moist soil. You’d be surprised, those vines root in just two or three days. Sweet potato is a very easy crop to grow. But it needs light, sandy ground. Sweet potato doesn’t grow well in hard ground. They need a chance to expand, and they need soft ground to do that. So that time on until harvest, the potatoes are growing underground and the vines aboveground. The vines get about ankle-high and spread, just like morning glory. Occasionally, they’ll put out a blue-and-white flower, about the same size as a morning glory flower. We might see only a few flowers an acre, and the flower is there for only two or three days, and then it’s gone.

“Sweet potato needs about 100 days to mature. From one plant you usually get three or four potatoes, a couple pounds. In California general harvest time is mid-September through October. The potatoes are harvested by machine, then mechanically sized and hand packed. They are stored in bins.”

Was sweet potato a profitable crop? “All of us farmers are in this for the money. Sweet potato isn’t particularly expensive to grow and in general is a plant that is more productive than most crops. For the amount of effort and energy you put in it, the yield is high.”

Did Mr. Whittman ever have a crop failure with sweet potatoes?

“No. You don’t know me, but if I was a poker player, I’m the kind of guy that bets on aces, straights, and cinches. We didn’t take any chances. We plant them in season. We never had a failure. They were very good to us. We profited.”

Did Mr. Whittman have a favorite sweet potato dish?

He laughed. “I don’t eat them much. I’m a California native, and I grew up eating white potatoes. My wife, though, is a Georgia Southerner, and when we got home from a trip, she always says, ‘Bring me some sweet potatoes.’ I’d have to say that I’m not a fan of the sweet potato, but I sure like the money.”

Sweet potatoes, like other agricultural products, have served as an organizing principle for growers and researchers. Sweet potatoes have the Sweet Potato Council, a national group with state subgroups. “The national council,”. Mr. Whittman said, “meets every year. There’ll be some two, three hundred people there, the same people, it’s a small industry. You find that you know almost everybody there. You hear about their kids, about somebody died, and somebody had a heart attack, and somebody had a good year, and somebody had a bad year. Researchers and market people that we get to come talk to us are there. The hotels where the conventions are held try to serve a lot of sweet potato dishes.

“About 15 years ago, we had the convention down at the Hilton on Mission Bay. I remember it was in early February and one of those times the Santa Ana winds were blowing, and it was 80 degrees. We had field tours, took the out-of-towners up to see the avocados growing on the hillsides. They really enjoyed that; farmers are farmers, you know, and they all like to see things growing.”

Robert Scheuerman, known to California farmers as “Mr. Sweet Potato,” heads the state Sweet Potato Council. Before Mr. Scheuerman retired several years ago from his post as a University of California farm advisor, he regularly sported a cap across whose brim was printed, “I Yam a Sweet Potato Man.” When early one morning I telephoned Mr. Scheuerman, who lives in Merced, in the heart of California sweet potato- country, he wanted to make sure that before we talked about sweet potatoes that I knew the difference between potatoes and sweet potatoes and yams.

Sweet potatoes are not really potatoes at all. Potatoes are tubers. Sweet potatoes are roots. Potatoes are members of the Nightshade family; sweet potatoes belong to the Morning Glory family.

“I like to use the word ‘yam’ in quotes,” said Mr. Scheuerman, “because yam in the United States is a market term that denotes a moist-flesh sweet potato and is not a botanical term.”

Although in the United States several varieties of sweet potatoes are marketed as yams, yams are not sweet potatoes. The true yam, an African and Asian native, like the sweet potato, is cultivated for its edible root. The yam’s starchy, swollen root in appearance somewhat resembles the sweet potato and is grown and prepared in the same way as sweet potato. The two plants, however, are not related.

When you go to your local grocer’s with sweet potatoes on your mind and start rummaging in produce bins, you will find a bin marked “Jewel Yams,” a bin marked “Beauregard Yams,” and a bin marked “Garnet Yams.” You will also notice a bin marked “Sweet Potato.” All these bins, in fact, are heaped with sweet potatoes. The sweet potato that your grocer labels as “Sweet Potato” will have a pale skin and pale yellow, relatively dry flesh. The sweet potatoes that your grocer labels as yams—the Garnets, Jewels, Beauregards — have darker skins, some almost maroon, and darker orange flesh that becomes moist after cooking. Typically, the Garnet will have a red to purple skin and a deep orange flesh that when baked is moist and almost dessert-sweet. The Jewel’s skin has a coppery sheen and an orange flesh that tastes a bit less sweet than the Garnet’s. The Beauregard (named, Mr. Scheuerman told me, after the Confederate general from Louisiana, Pierre Gustave Toutant Beauregard) has a rosy skin and orange flesh; its sweetness is similar to the Jewel’s.

“The famous University of California at Davis professor Jack Hanna, who bred the [mechanically harvestable] tomato 25 or 30 years ago,” said Mr. Scheuerman, “also bred the Garnet variety sweet potato and the Hanna, a dry-flesh-type sweet potato. But of course,” he added in funereal voice, “Jack Hanna’s dead now.”

True sweet potatoes are native to Central and South America and were a primary ingredient of the Aztec diet. When Columbus sailed back from New World to Old, sweet potatoes were among the vegetables he took to Spain. Vegetables and fruits brought to the Old World from the New initially tended to be regarded as either poisonous or aphrodisiac or both, as was the case with tomato and white potato. The sweet potato, while not thought poisonous, was believed to increase erotic capacity.

From Spain, the sweet potato went to England. By the 17th Century the belief in sweet potato’s aphrodisiac power was sufficiently prevalent to permit Shakespeare to make mention, without explanation, of sweet potato’s connection with Eros. When in Merry Wives of Windsor the love-besotted Falstaff greets Mistress Ford with “Let the sky rain potatoes,” the potatoes to which Falstaff refers are sweet potatoes.

The sweet potato returned to the New World with English settlers and was growing in Southern colonies by 1648. In the opening days of the Civil War, said Mr. Scheuerman, some one million acres of sweet potato were under cultivation below the Mason-Dixon Line. “The Civil War,” he added, “was fought by the South on a diet of sweet potatoes.”

In the South, the slaves, already familiar with an African yam they called nyami, gave the name “yam” to the sweet potato. The name stuck.

Once we’d cleared up the potato/sweet potato/yam confusion and gotten down some sweet potato history, Mr. Scheuerman, who even in retirement remains head man for the California Sweet Potato Council, wanted me to know that in the United States, after North Carolina and Louisiana, California is the third largest producer of sweet potatoes. “People don’t think of California,” he said, “when they think sweet potato.”

California acreage devoted to sweet potatoes hasn’t changed much in the 31 years Mr. Scheuerman has been in Merced County. “Acreage goes up and down, depending upon price. It varies between six and nine thousand acres. Several years it went as high as 10,000 acres, statewide.”

I asked Mr. Scheuerman if many farmers grew sweet potatoes in Southern California. They had, he said, but because of land costs, not as much as formerly. In fact, he added, where Disneyland is now was once planted in sweet potato.

Almost all of California’s sweet potato crop is sold as fresh market produce rather than for processing. (And it’s a shame that when most people think “sweet potato,” their mouths remember slimy orange chunks stacked in cans and bathed in grainy liquid.) Mr. Scheuerman said that he was not just bragging when he said that the best-looking, best-tasting sweet potatoes in America grow in California. “There’s a reason,” he said, “why that’s true. Our sweet potatoes don’t get as much rain as they do in the Deep South, and because they don’t get wet and because, generally, they grow in a sandier soil, they don’t become misshapen and lumpy. In California, the shine on our potato skins is so high that we don’t even have to wax our sweet potatoes, whereas in the Southeast and South there is some waxing done.”

I asked Mr. Scheuerman how he happened to get interested in the crop. He said that when he started out as a farm advisor he consulted with farmers on all of Merced County’s veg crops. Sweet potatoes, then and now, were one of the most important crops in Merced County. “Back then, though, not much work was being done in sweet potatoes. They had a lot of problems and nobody to solve them, so I thought this would be a good challenge.”

Farmers began planting sweet potatoes in Merced County in the 1860s. “In the beginning,” said Mr. Scheuerman, “sweet potato farmers were mostly people of Portuguese descent. After World War II, when the Japanese returned from internment camps, they got into sweet potatoes. Now Merced County sweet potato growers include Greeks, Mexican-Americans, together with descendants of some of the pioneer Portuguese and Japanese growers. There are several farmers who grow only sweet potatoes. You can make good money if the price is right. There have been a few bad years. Generally, overall, though, sweet potatoes have been good to growers.”

Mr. Scheuerman belongs to the National Sweet Potato Collaborators, a research group of some 100 specialists in sweet potatoes. On a quarter-acre plot in Livingston, in Merced County, Mr. Scheuerman over the years has tested more than 50 varieties of sweet potatoes. “I was always trying to hit upon a better sweet potato for California growers, a product that would look better and taste better and have more disease resistance.”

Of sweet potato’s various diseases, the most serious have been those that are soil-borne. “Soil pox and soil rot, diseases similar to potato scab in Irish or white potatoes, have been about the worst,” said Mr. Scheuerman. “The soil pox gets in the soil and you just can’t seem to get it out. I have been testing for it for years and years to get pox-resistant sweet potatoes. Now we do have pox-resistant potatoes for the yam types and red types and dry types. That was one project I wanted to complete before I retired.”

I asked what soil pox looked like.

“It shows up on the potato itself as a scabby indentation. In some varieties, when the pox gets to them, the vine itself will die or be stunted. Some varieties, the vine goes well, and then you dig them and find them with the pox.”

One technique for developing disease-resistant plants involves acquisition of wild varieties with which older varieties can be bred. “A lot of the wild materials for sweet potato,” says Mr. Scheuerman, “is gotten out of the mountains of Peru, where the sweet potato is indigenous. Breeders go down there and get the wild species and bring them back and crossbreed them with the domestic types. We also get new varieties for experimental breeding from other states. Louisiana and North Carolina have intensive breeding programs, and they’ve provided us with quite a bit of material.”

When Mr. Scheuerman was working full-time, did he ever go to bed and find himself worrying about the sweet potatoes?

“Oh, you bet. When you have an interest in something, you always do that. Sweet potato is an intriguing crop. It grows under the ground, so you never know what you are going to get until you get it out. Crops that mature above the ground, you usually have an idea of what you are going to get in the end. But with sweet potatoes, you never know until you dig them out and see the numbers and the quality and how they perform, one variety against another. Yup, it was exciting.” Mr. Scheuerman paused a moment before he spoke again. “The biggest surprises were to see if these potatoes were resistant to potato pox, because we worked a long time on that and finally, just this past year, found a resistant red, which I was trying to find for the last 20 years. So now I think we have a few that the growers can grow, if they want to.”

I asked what these new pox-resistant potatoes were called.

“They have no name yet, they’re still just numbers.”

I suggested that perhaps one of these new potatoes eventually will be named after him.

Mr. Scheuerman laughed. “My name,” he said, “is too long for anything to be named after me.”

Unlike San Diego’s Bill Whittman, Mr. Scheuerman regularly eats sweet potatoes. He likes his baked. “They taste good,” he said, “and they’re good for you. One sweet potato will give you all the vitamin A and carotene that you need for the day.”

The yellow-orange pigment carotene occurs in both animal' and plant tissue. Egg yolks’ color, for instance, comes in part from carotene. When carotene occurs in plant tissue, it is classified as beta-carotene. Among natural sources of beta-carotene are grapefruit, cantaloupe, watermelon, apricot, broccoli, Brussels sprouts, carrot, pumpkin, squash, bell peppers, spinach, kale, papaya. In dark green vegetables like kale and broccoli, you do not see beta-carotene’s orange color because the green pigment chlorophyll masks the beta-carotene’s orange.

Although most of us tend to think of raw vegetables as more nutrition-rich than cooked vegetables, this is not true with vegetables from which we wish to coerce the last bit of beta-carotene. These fruits and vegetables should be steamed, juiced, pureed, or mashed to rupture cell membranes and make beta carotene more readily available for absorption. When we do eat beta-carotene-rich vegetables and fruits raw, we should chew as assiduously as we can to break down the cell walls.

Not until beta-carotene is taken into the body does it become vitamin A. Specifically, this conversion occurs in thejiver. Vitamin A, together with vitamins D, E, and K, is stored in body fat and released on an as-needed basis. Because vitamins A, D, E, and K are stored in body fat, they can, in rare instances, accumulate in quantities that become toxic.

Even if all you have is a patio. Bill Whittman said you can grow at least one sweet potato plant. Start by filling a wide-mouthed canning jar with water, almost to the top of the jar. Place in the jar’s mouth a sweet potato with the potato’s pointed end in the jar. Make sure the potato makes contact with the water.

Place the jar near a sunny window. Within two weeks, vines will have sprouted from the potato. In May, pinch off a six- or seven-inch piece of vine and stick the bottom two inches of the vine in a barrel or large box filled with soft, moist soil. You can do the same thing, of course, in a garden plot. By late September, early October, you should have sweet potatoes.

Sweet potatoes vine so easily that my friend Jerry, a first-grade teacher, uses sweet potatoes in the classroom as a lesson about the tenacity of living things. “Every year, for the past 13 now he said, “I’ve had kids build mazes in shoeboxes. They cut a hole into one end of the shoebox, then another in the opposite end. They build the maze in the middle of the box, then put the lid back securely, on the box. The sweet potato they place in a canning jar filled with water. Once the vines start to grow, the children feed the vine into one end of the shoebox. In a couple of weeks the vine has found its way through the dark maze and is popping out of the other end of the shoebox. It’s a very strange-looking thing, this pale sweet potato vine curving around in the dark box and finding its way out to the other end. It always makes me think of the slaves following the North Star to the Mason-Dixon Line, following the light.”