We've cracked the secret to Michelle Obama's chiselled arms: digging up spuds. The First Lady has created an edible garden at the White House - proving that growing your own has shifted from hippy hobby to mainstream activity. And there's good reason to follow her muddy footsteps. Growing vegies, fruit and herbs slashes your food miles and save you money. By choosing vegie patches over a lawn, you'll also cut water usage - Aussie households use 40 per cent of their water on gardens, 90 per cent of which is on their lawns. Oh, and an hour of gardening torches 1000kJ.* The trick to turning that thumb even greener, says Mary Trigger, CEO of Sustainable Gardening Australia, is to garden organically: "This means no petroleum-based fertiliser, pesticides or herbicides that may get washed into drains. Once in waterways, they dissolve, or combine with other chemicals to create harmful combinations that kill aquatic life. Chemicals can also drift through the air and kill plants or bees." Use organic compost, which you can make by chucking food scraps and green waste into a compost bin (this will practically halve the waste you send to landfill).

All you need for an edible garden is a little bit of space, sunlight, healthy soil and water. Doesn't sound too demanding. We asked Melbourne horticulturalist Kay Hurwitz for two easy gardening projects...

If you have a yard
"Choose a sunny spot, dig a wide trench and put the soil aside. Fill it with compost, then shovel the saved soil on top. Tada! Your first garden beds." What you grow depends on your climate, so Hurwitz suggests asking at a local nursery or checking seed packets. Some good picks for winter: lettuce, onions, peas, broad beans, rhubarb and strawberries. "Pick produce as it's ready, but if you let a small percentage of the plants grow old enough to drop their seeds into the soil, another batch will emerge without you replanting or spending a cent."

If you have a balcony
You can grow a surprising amount in a pot or windowbox. Hurwitz recommends using terracotta and ceramic containers or even recycled polystyrene and plastic boxes. "Cut drainage holes at the bottom, then fill the containers with potting mix and compost," she says. "Then use a seaweed concentrate, like Seasol (seasol.com.au), on the seeds or seedlings at the time of planting, then once a week for four weeks to stimulate plant growth." Some container-friendly foods to plant: carrots, cos lettuce, peas, spring onions, chives and parsley.

Join the green gym
It's a whole new way to work out: instead of sweating it out in a brightly lit studio, Conservation Volunteers "Green Gyms" help you get fit by planting, weeding, digging and building tracks. Not only is there no joining fee, the whole program costs nada - you just need to commit to 12 weeks of two four-hour sessions per week.

Organisers claim that working out in the fresh air can reduce stress levels and risk of heart disease and stroke, as well as improve muscular strength and fitness - all while benefiting your local area. We'd guess it's a whole lot more sociable than spin class, too. There are currently five Green Gyms operating in Victoria and NSW, with plans for more around Australia. See conservationvolunteers.com.au/greengym.htm for more info.