It is also difficult and requires time and knowledge to be able to reliably do this, and even then some plantings will fail due to unforeseen reasons. Someone with time or budget pressure would have a hard time doing this on their own.
Yes, there's the cost of getting it and tending it, but there are advantages in positive mental health and exercise (with bigger yards) and some hippy "feeling connected to the world" stuff.
Eatings peas just off the plant is great.
Even herbs and spices can be grown if you just have a window sill.
But, yes, it's not for everyone. Some people just don't like that kind of thing.
I live in the suburbs but with a very small backyard. I have about 60 sq ft of space that provides 90% of my vegetables throughout the year. When I lived in an apartment I had two tomato plants and two squash plants on my deck and it would give me pounds of food a week (squash grows really quickly, tomatoes grow abundantly).
It's not impossible by any means for most people to do so, even in small quantities.
http://www.mypatriotsupply.com will send you a can of seeds, 20 varieties, enough to cover an acre, "heirloom" (seeds from plants are re-usable next year), for $40.
But in any case, if you can trade a few hours for $500 at will, you probably can spend more than £1/day in food. Most people can't just work a few more hours (if they have a job at all) though.
