Someone weighing around nine stone will burn 150 calories in half an hour of digging, while non-motorised mowing typically burns around 165 calories per 30 minutes, according to research from Harvard Medical School.

Raking the lawn for 30 minutes burns around 120 calories - the same as the calories burned in a half hour of Tai Chi, volleyball and even horseback riding - while half an hour of splitting wood burns the same amount of calories as half an hour of vigorous weight-lifting, research suggests.

Try squatting when you're weeding or planting and you'll use a mass of muscles in the process. Stand on one leg while pruning, digging or clipping, which will stretch you and increase suppleness. Don't always get out the ladder. Instead, get on your toes on one leg if possible and stretch to reach.

Bunny Guinness, award-winning garden designer and co-author of the book Garden Your Way To Health And Fitness, says: "The wonderful thing about gardening is that, unlike repetitive exercises at the gym, it can provide all over-body fitness - raking, weeding, digging and other gardening tasks all use different muscles and test your body in different ways."

Guinness, who was diagnosed with a slipped disc aged 11, but has worked on her core over the years with the help of foam rollers and back strengthening exercise, continues: "People don't realise how many calories exercise in the garden uses up.

"If I went to a gym and did a good workout - 20 minutes on a rowing machine, 20 minutes on a running machine and 20 minutes on a cross trainer - or spent three hours in the garden mowing the lawn, weeding and pruning, I'd use up the same amount of calories."

Warm-ups are important, especially if you've been a couch potato over the winter months, she stresses.

"It's best to limit your activity on one thing, so rotate your garden jobs - don't spend hours digging a border all at once - and, most importantly, stretch, which makes a huge difference to me. If I don't stretch at the end of the day when I'm warm, I really stiffen up afterwards."

People with a small garden who are going to find it hard to do enough aerobic exercise can use up energy doing step-ups on their existing steps or a wooden bench, she suggests.

"You are not going to be carting wheelbarrows for miles, so it's good to mix it up with other things. You can do bench presses and other exercises on a simple garden bench. Some people have monkey bars for upper body exercise.

"If you are raking - which is like a lunge - try to use your other side. We tend to use just one side of our bodies, but you will get used to using the other side too."

Classic back problems associated with gardening can be avoided if you make your core muscles as strong as they can be, she says.

"When you are lifting a heavy pot, squat down and use your core muscles to lift it up, pulling it close to your tummy and then stand. You really don't want to be twisting and having the weight out from your body. Foam rollers are brilliant to help you realise where your core muscles are."

If you want to be super fit, combine gardening with a more traditional work-out and avoid shortcuts like ride-on lawnmowers, leaf-blowers and other tools which avoid having to pick things off the ground.