How much land do you need to be self sufficient? Again inspired by Red State Green’s recents posts I decided to do some research on my own. Prior to this, in a comment on “A matter of national security”, I used some somewhat high output figures I found on another site that basically said about 0.11 of an acre would be all that is required for a family of four. I decided to find some better numbers and also instead of just going by 2000lbs of food per year per preson, use the recommended portions of the CanadaFood Guide.
Assuming everyone followed Canada’s food guide, and using chicken for meat and dairy alternatives and/or trading or somehow offsetting the cost of purchasing some of the food, this is how I see it breaking down (weights of food taken from http://www.stambaughfamily.com/equiv_1.html):
Food Guide per adult male:
10 servings (1/2cup) of vegatables and fruit. Lets say your servings are 1 cup of tomato, 1 cup of spinach, 1 cup of carrot, 1 cup of cabbage and 1 cup of potato. That corresponds 74kg of tomato, 50kg of spinach, 55kg of carrot, 110kg of cabbage, and 83kg of potato per year.
8 servings of grain products. Lets use 4 servings of oats and the equivalent in flour of four servings of bread. That corresponds to 21kg of oats and 20kg of wheat flour per year.
2 servings of dairy. Lets assume soy drink, 1 cup ea. or approx. 23kg of soya beans per year.
3 servings of meat and alternatives. Let’s use chicken for all three (75g ea.) That’s 82kg per year.
More after the fold.
These calculations when applied to food guide amounts for an adult female and two 9-13 yo children result in:
222kg of tomato
150kg of spinach
165kg of carrots
330kg of cabbage
249kg of potato
71kg of oats
68kg of wheat
138kg of soya
246kg of chicken
Outputs per acre for these crops, taken from various sources and hopelessly approximate (there are no authoratative datasets that I can find but I mostly used the following site: http://www.gardensofeden.org/04%20Crop%20Yield%20Verification.htm), shape up to the following space requirement for our fictional family:
0.044 acre for tomato
0.030 acre for spinach
0.019 acre for carrots
0.053 acre for cabbage
0.036 acre for potato
0.070 acre for oats
0.024 acre for wheat
0.145 acre for soya
0.006 acre for chickens (minimum, not free range and not counting space for growing feed, if required)
That equals 0.427 acres, not too bad, about 0.1 acres per person. Of course, it doesn’t make sense to try and grow EVERY part of your diet your self, the 0.145 acres for soya for milk alternative is a little excessive and trading with a local dairy farmer might make more sense. Without the soya and say doubling the chicken as a trade for the milk, you get 0.288 acres! The space required to grow feed for your chickens, might increase the total to about 1/3 of an acre, but using even a small portion of your land to produce a more valuable commodity like say more tomotoes could easily cover the costs of buying feed from another grower. This does not count feeding table scraps peeling to you chickens which they love and reduced the need for grain feed.
So it seems by this simplistic exercise that a maximum of 1/2 an acre should give you everything you need to be self sufficient food wise. Of course, there may be higher yield crops out there and this does not take into consideration mixed gardening which can increase output per acre as some crops can use the same piece of land during different times of year. Nor does it take into account the possibility of using permaculture and greenhouse techniques to boost productivity.
Realistically, a family of four growing just their vegetables on about 1/4 acre (about a 100′x100′ plot) would be a huge amount of their food supply and quite manageable if you were willing to put in the work! Of course city dwellers and some suburban homes may not have a 100×100 plot to work with, but those of us who do should be taking advantage of our resources. From a cost standpoint the food costs for these veggies (using Strong’s Market prices):
222kg of tomato $483.96 + taxes
150kg of spinach $1584.80 + taxes
165kg of carrots $178.20 + taxes
330kg of cabbage $283.80 + taxes
249kg of potato $323.70 + taxes
For a grand total of $2,854.46 + taxes, I don’t know about you but for a few hours (or more) a week and the cost of a few packets of seed and tools, I’d say it’s a pretty good return.