Is it really cheaper to cultivate your own fruit and vegetables?

It is an article that seems to come around every year: the promise that the average family can save money by growing their own fruit and vegetables. Whether they echo “dig for victory” wartime nostalgia or romantic pioneer spirit, the writers never really reference how they arrived at the stats they use. So can your average home gardener really compete on price against the economies of scale of industrial agriculture? Let’s crunch the numbers.

Say you want to start with one of those bucolic, wooden potato-growing planters you see in gardening catalogues. In the UK, these…