I had my first visual proof of Allen Fowler’s gardening prowess a couple of years ago, when he sent me a good-natured e-mail to tell me I was wrong. At issue was my claim that the length of the growing season in the northern United States makes it difficult to produce a significant crop of sweet potatoes before frost arrives in October. Allen, a 70-something retiree with a digital camera, spread his massive sweet potato harvest out on a long table and e-mailed me a photo.

Yes, I was humbled. And impressed. Not only were the sweet potatoes numerous, but some of them were as big as your foot. Later, he also sent me a photo of his even more majestic tomato harvest.

Last week I drove up to southern Leavenworth County to meet Allen and his wife, Rosie, and to see the garden that produces such bounty. I was not disappointed.

Although the vegetable garden was the purpose of my trip, I wouldn’t do the Fowlers justice if I didn’t mention their orchard, which produces cherries, pears, peaches, apples and pecans, or the gorgeous flower beds that Rosie tends. Any self-respecting vegetable would be pleased to grow in this setting.

Although the vegetable garden is now Allen’s project, Rosie has earned her stripes. She and her sister-in-law, the late Rosetta Lee, were among the first vendors at the Lawrence Farmers Market. Allen and Rosie tell of setting out 500 tomato plants in the 1950s and selling the fruit for 10 cents a pound, delivered, to restaurants and other large customers who would take 10 pounds at a time.

Then, vegetable gardening wasn’t quite as mainstream as it has now become, Allen said.

“Back in those days people really looked down on you for growing stuff like that, like you were real poor trash. Now people really go for it,” he said.

Allen’s 3,000-square-foot garden, which is surrounded by a 5-foot fence that is hot-wired to keep out deer and rabbits, is a show-stopper. Bird houses sit atop the fence posts and larkspur, iris, cannas, tulips, honeysuckle and cleome add color and attract beneficial insects. The vegetable garden also is home to peonies that he and Rosa have had for the more than 50 years of their marriage. Those peonies moved with them in 1983, when the Fowlers pulled up stakes in North Lawrence and headed to the country.

Raspberries, strawberries, asparagus, horseradish, lettuce, onions, radishes, peppers, carrots, snow peas, cabbage, red and white potatoes, sweet corn, zucchini, cucumbers, green beans and, of course, sweet potatoes are planted in Allen’s garden.

Our tour paused at the sweet potatoes so Allen could rub it in a little. The plants still may be compact this early in the season, but Allen assured me that will change once they start to vine.

“Those things will run from here to clear past those carrots,” he said, pointing to a row about 15 feet away.

But when Allen turned to his tomato cages, it was clear that everything else was just a backdrop for what he likes growing best.

“That’s my pride. That’s my real garden,” he said of his tomatoes.

From two dozen plants (Better Boy, Celebrity and Early Girl), Rosie will can 200 quarts of tomato juice in a good year. That’s 2-0-0. And most years bring good tomato crops in Allen’s garden.

Allen has a wire stretched through the tops of each cage and on down the row, so that he can gently shake all the plants at once, simply by jostling the wire from one end of the row. This improves pollination, he said.

“I also let my suckers grow. I used to take them off, but I’ve found that the suckers provide shade for the tomatoes,” he said.

Before Allen sets the tomato plants in the ground, he tills triple-12 fertilizer (a nitrogen-phosphorus-potassium ratio of 12-12-12) into the soil.

And then there’s the dirt itself, which Allen has amended with plenty of leaves and other vegetation over the years, to produce soft but robust soil that spills through his fingers. He saved a rock-hard clod from the first tilling, now more than 20 years ago, to show what is possible.

Now I can’t wait for the next batch of pictures.