Gardeners' answer lies in the soil

Feeding a family of four from the garden is possible with only half an hour of work a week, says soil ecologist and self-proclaimed "dirt doctor" Jim O'Gorman.

Families had drifted away from having a backyard garden as vegetables had become so easy to get from the supermarket.

However, a vegetable plot, 10m by 15m, would supply everything a family of four would need from the garden, Mr O'Gorman said.

"That is not a big garden plot. Once that is up and working, you will find it doesn't take much to manage at all.

"My assertion is if you look after your soil, your soil will look after your plants."

By focusing their gardening on the soil and understanding the good micro-organisms that lived there, people could bring their soil to life, he said.

Mr O'Gorman, who runs Half-hour Urban Eden workshops on how to manage a garden plot on just half an hour a week, advises beginner gardeners to "make your compost, make your compost and keep it coming".

People had to learn to see everything around them in the garden as resources, not waste or rubbish, he said.

"When you go out and go to the beach, take a sack and pick up a piece of kelp. Be aware of what's around you."

Collecting up these "resources" and using them for compost and mulch does a lot for the garden.

Most of Mr O'Gorman's research in his own garden plot at Kakanui, had been to understand the value of weeds in the garden.

Weeds were not always bad, he said.

"It is not that you have weeds. It is what weeds you have and how you manage them."

For example, garlic and onions hate competition from weeds, but plants such as broccoli and cauliflower will stand up above the weeds, which means spending time weeding around these plants is unnecessary.