The charity also found that it could shave up to £350 off the average yearly grocery bill.
The organisation's research found the food and drink carbon footprint of those who took part in the study was six per cent lower than the UK's average each year.
Garden Organic chief executive Myles Bremner said: "There is no need for the food we consume to travel thousands of miles, when we can grow it in our back gardens."
He added that the people surveyed also tried to limit the amount of waste they were producing by creating their own natural fertilisers and composts to help their plants grow, "eradicating the long supply chains and the heavy associated carbon footprints that come with buying these supplies from DIY stores".
Other findings in the Garden Organic study included:
- Organic growers surveyed had a carbon footprint of 7.4 tonnes a year - 66 per cent lower than the national average;
- Despite only using just over half of their garden space, organic growers were able to produce more than 50 per cent of the fruit and vegetables they consumed in a year;
- If the average garden (733sq m) was given over to fruit and vegetable growing, householders could grow 98 per cent of the fresh produce they consumed each year, only metres from their back door;
- Sixty per cent of organic growers eat their own produce daily.