Tomorrow is the best day to begin a diet. Not because today you can’t resist fudge brownies, but because tomorrow is when the moon says it’s best.

Selecting the best date for a task based on moon signs is actually a centuries-old practice that has helped guide people on when to do everything from planting potatoes to picking mushrooms. And it’s still being used today.

“It’s an astrological, not to be confused with astronomical, practice or tradition,” says Janice Stillman, editor of The Old Farmer’s Almanac, a publication that has included a calendar of astrological information since its first publication in 1792.

According to the almanac, the best dates for a task are based on astrological placements of the sun, the moon and the planets in the 12 signs of the zodiac. Ancient astrologers believed that each astrological sign influenced a specific part of the body: Aries was the head, Taurus, the neck and so on down to Pisces, the feet. So, according to the 2009 Old Farmer’s Almanac moon sign dates in March, the best times to lose weight this month were March 14 and now March 24. Next month, your best bets are April 10 and 20.

“It works,” says Jackie Mielke, of Kidder, Mo. “We do a lot of things by the moon signs.”

Her recent success story began last November when she wanted to save money by having her hair cut on the best date for discouraging growth.

“My hair didn’t grow and didn’t grow. It’s now been six months, and I’ve only had it cut once. If you want to save money on hair, that’s the way to do it. Just don’t tell your beautician.”

Pat Leer, also of Kidder, Mo., uses the moon signs for weaning calves. She says when you wean them, you can usually tell, because the mothers and calves stay close to the fence and they are all bawling. But that’s not the case when this is accomplished on the best date for weaning according to the moon signs.

“I’m a firm believer in weaning by the moon signs, because I weaned our youngest son by the moon sign and left almost immediately for California and had no problems,” she says. “I gave him a bottle that morning, and from that point on he had a cup. When we were in California, my husband’s aunt offered him a bottle and he spit it out.”

Planting by the moon can give gardeners a bit of an advantage, Ms. Stillman says. It is believed that in the same way that the moon affects the tides, the moon affects the flow of water through the soil and throughout the plant.

“It’s a very subtle impact, but big enough to affect plants when they are just getting started,” she says.

According to a moon signs pamphlet given out by the Earl May Seed and Garden Center in St. Joseph, plants that bear their crops above the ground should be planted in a favorable sign when the moon is increasing, known as the light of the moon. Those things that bear their crops below the surface should be planted when the moon is decreasing, known as the dark of the moon. You always should consider the local weather, too, but for March, the best remaining date for planting perennials is the 24th. Plant leafy annuals on April 1 and 2. Your next best date for destroying pests and weeds is March 26 and 27. Ready to call it quits? Today is your day.

For more personalized dates, log on to Almanac.com and you can search for the best dates based on your location.

Lifestyles reporter Sylvia Anderson may be reached at sylviaanderson@npgco.com