Down Under On The Bucket Farm wrote:
...I am working on long-term plans for self-sufficiency, oriented to
buying some bare land and building an off-grid house, rainwater
catchment, composting toilet, etc, etc.
One issue is the question of how much physical space would be
needed to grow enough food to completely support myself?...

I do understand the risk of, for example, having a bad year, bad
weather, etc, and so would have money set aside to buy food in
that case. But the plan is to avoid that if at all possible.

I live in New Zealand, with plenty of rain in winter, but also
reasonable sunshine in summer...





No definite answer to this one. Too many variables. However, there is a
book, written probably in the 1940's (judging from the illustrations),
called "5 Acres and Independence", author's name escapes me at the
moment, but I think it starts with a K. It's full of receipes for
various necessities such as building your own septic tank, root crop
storage, etc., so although it's dated it might contain something of
value.

You will have to grow more than you need, because you will need some
money to buy (or trade for) stuff you can't grow (e.g. salt [unless you
have a salt mine or live by the sea])

Just Googled the book, author Maurice Kains. Available at Amazon.com
(reprint, paperback $7.95US, some used copies cheaper). Check your local
library.