NEW YORK - Spring is here and people everywhere are getting back to their gardens.

Experts say whether you're planting lilacs, squash or roses when it comes to the fitness benefits of all that pulling, digging, mulching and mowing,  you'll reap what you sow.

"You get exercise whether you're mowing the lawn or planting a flower garden," said Bruce Butterfield, market research director of the nonprofit National Gardening Association (NGA).

"Some of it is more rigorous, some less," he added.

Last year about 68 percent of all US households participated in one or more types of do-it yourself lawn and garden activities, according to a national Harris Poll conducted by the NGA.

"That's about 80 million households," Butterfield said.

And a 2009 poll found that of those, 38 percent gave gardening a green thumbs up as a great form of exercise.

The effort involved in planting a garden, such as standing, stooping, kneeling, watering, and weeding, can burn more than 300 calories an hour, according to the American College of Sports Medicine's (ACSM) Health and Fitness Journal.

Neal Pire, an exercise physiologist with ACSM, said lower back stress is the most common weed in the fitness garden, especially if, after a winter of inactivity,  you run outdoors on  first day of spring to garden the day away.

"Start slowly," he advises, "and progress a little more each successive day."

Jeffrey Restuccio, author of book "Get Fit Through Gardening," is a martial arts expert keen to transform gardening, generally categorized as a moderate-intensity exercise, into a comprehensive fitness program.

"It's the difference between being sore and having an aerobic activity," said Restuccio, who urges gardeners to lower their centers of gravity to more of a boxing stance, and crank up the cardio with lunges and moves from Tai Chi and Tae Kwan Do.

"You're gardening to exercise not exercising to garden," he said.

Whether you're after blossoms or biceps, proper form is key to safety, according to Jessica Matthews, an exercise physiologist with the American Council on Exercise.

"Sometimes I watch friends garden and the body mechanics are horrendous," Matthews observed. "Make sure you're bending at the knees, and using your leg muscles to perform good movement."

Gardening can work both the cardio and resistance components of fitness, Matthews explained.

"Cardiovascular involves movements like mowing the lawn with a push mover, raking or blowing leaves," she said. "Resistance would focus on pulling weeds, hoeing, and digging."

Nationwide, the average time spent on gardening activities is 3.4 hours a week per gardening household, according to the NGA, well short of the 150 minutes per week recommended by most physical activity guidelines.

"But other things can supplement," Matthews said. "Warming up is always ideal. Start with a 10-minute walk to loosen those muscles, get heart rate up, and add a little more exercise. Throw in some stretches," she said.