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WINNING LETTER

THE MATHS BEHIND THE HARVEST

I grew these 15.5 kg of New Zealand yams (oca) and 10 kg of potatoes, organically, on eight square metres of land. The total number of hours that went into sowing, growing and harvesting the crop was six.

I could sell these tubers, wholesale, for $80 (which would pay me $13.30 an hour for my work), or use them to fuel me for 10 days (an average woman consumes around 1600 calories per day). Sometimes, the maths of self-sufficiency is fun to do. But if I was an organic grower, selling vegetables for a living, these figures might seem a