Wearing protective clothing is one good way to reduce exposure to the sun.

AP / Martha Stewart

Perhaps it’s fitting that a food product — the seedless grape — was the image picked for a major anti-sunning campaign. Gardeners are among the most at risk for developing skin cancer.

All that weeding and watering, mowing and mulching was once considered a happy way to build a tan. But years of sun exposure can have a terminally dark side.

“A raisin is a grape that didn’t have the sense to get out of the sun,” The Skin Cancer Foundation says in a new series of public service print ads. “There is no such thing as a safe tan. ... Go with your own glow.”

Get the picture, gardeners?

More than a million cases of skin cancer are diagnosed annually in the United States, with one in five Americans developing the potentially fatal disorder. And the more time spent in the sun, the greater the risk, says the Centers for Disease Control and Prevention.

The average gardener spent 2.8 hours a week on the hobby, according to Bruce Butterfield, research director for the National Gardening Association.

“Because of increased sun exposure, gardeners and farmers are at higher risk for skin cancer,” says Dr. Robin Friedman, a dermatologist from Memphis, Tenn.

Sun avoidance is the best deterrent, although that’s not a real-world solution for people whose jobs or activities require them to be outdoors. So here are some practical sun safety suggestions:

• Work in the cool of the day or before 10 a.m. and after 4 p.m. Do not discount the solar radiation danger from an obscured sky. “You can get some of the worst sunburns on a cloudy day,” Friedman said

• Inspect your skin head-to-toe at least once a month. Remember the shape of mole and freckle patterns and then note any changes. “Examine yourself everywhere,” Friedman said. “You can get melanomas on the bottom of your feet, between the toes, on your scalp. Pay particular attention to exposed areas.”

• Make a yearly appointment with a dermatologist. Early detection is key, particularly for melanoma, which has a tendency to invade other parts of the body.

• Use a product with SPF 15 or higher. Apply it at least 15 minutes before going outdoors, and reapply every two hours.

• Wear sun protective clothing, including a broad-brimmed hat, loose-fitting smock, trousers, gloves and UV-blocking sunglasses. “This is an excellent option for gardeners,” Friedman said. “Such clothing is designed to protect the back of the neck and other areas exposed to the sun while doing all that bending and stretching.”

In Australia, where skin cancer is more prevalent than lung cancer, sun-protective clothing is tested and rated by a federal agency, said John Barrow, a transplanted Australian who started the Coolibar clothing line to the United States seven years ago.

“Something like four- or five times as much money is spent on (Ultraviolet Protection Factor-rated) clothing in Australia than on sunscreen,” Barrow said. “It’s easier to use. Put the smock on or the hat on and you have it done.”

On the Net:

Skin Cancer Foundation: http://www.skincancer.org

Sun protection’s alphabet soup

Do letters like UPF and UV sound like alphabet soup? Here’s a glossary of skin protection terms:

• ABCD’s of melanoma: Look for these warning signals during your monthly skin cancer self-exams. “A” is for Asymmetry. Draw an imaginary line through your mole. Do both sides look alike? If not, The Skin Cancer Foundation recommends that you see a dermatologist. “B” is for Border. Check the outside edge of your mole. Are its edges sharp and easy to distinguish from the surrounding skin? If the edges look ragged or fuzzy, then schedule a trip to the dermatologist.

“C” is for Color. Examine the color of your mole. Is it the same all over or does it vary in shade, from dark brown to red or blue? If it does, then visit a dermatologist. And “D” stands for Difference. Have any of your moles changed recently in size, shape or color? Have they suddenly become itchy? Does one look markedly different from the others? If so, then make an appointment with a dermatologist.

• UVR (ultraviolet radiation) comprises long-wave (UVA) and short-wave (UVB) rays. Both can penetrate glass and clothing. Their effects are cumulative, leading to skin cancer, skin aging and eye damage.

• UV Index. Developed by the National Weather Service and Environmental Protection Agency to forecast the expected risk of overexposure to the sun. Intensity levels vary from 1 to 11+ with the higher numbers indicating increased risk. A daily index by ZIP code is available at the SunWise Web site: www.epa.gov/sunwise/uvindex.html .

• SPF or Sun Protection Factor numbers rate the protection provided by the various sunscreens. The higher the SPF number, the greater the degree of protection.

• Ultraviolet Protection Factor (UPF) is the clothing equivalent to the SPF numbers for sunscreens. The numbers can run from 0 to 50+. The higher the number, the greater the degree of protection. Testing indicates that a UPF 30-rated fabric that blocks or absorbs 29 of 30 units of ultraviolet radiation blocks 96.7 percent of the UV striking it.