Sustainable Building Forum

People say that growing your own food is part of sustainable living. Its not cost effective. If you sum total the amount spent on menures, fertilizers and water as well as the time spent on tending the garden, buying vegies is much cheaper. Yes, I don't burn the fuel to go to the vegie shop, but I go the nursery to buy seeds and manure. I love gardening anyway and organic food is good for my health but my question is - Does gardening really help the environment?