A sense of connection to other people is important, but so too is the individual connection to nature. One Harvard University study showed that people who were surrounded by lush greenery lived longer, with a lower chance of developing cancer or respiratory illnesses.

Doctors in Scotland can now prescribe a walk in nature to treat a variety of ailments, including reducing blood pressure and anxiety, and to improve overall happiness. Gardening – even on a small plot in an urban area – is a simple way to incorporate more nature into your daily life.

Finally, there is also a dietary component to longevity that gardening can help with. Researchers have demonstrated a link between the “Mediterranean diet” – rich in vegetables, fruits, whole grains, legumes, nuts, fish and olive oil – and slower aging.

Willcox says the fundamental principle of eating an abundance of fresh vegetables, ideally from local gardens and markets, is important to longevity, whether the diet is technically Mediterranean or not. In Okinawa, for example, most people grow vegetables such as bitter melon and sweet potatoes in their gardens.

“When you eat vegetables that you’ve grown yourself, it changes everything – they taste more delicious, and it really makes a difference in the health qualities (vitamins, minerals, phytoactive compounds etc.) of the food itself,” says Willcox. Buettner, the “blue zones” expert, recommends a diet of “90% plants, especially greens and beans”, and points out a simple truth: gardeners are more likely to plant what they want to eat.

Farming for a longer life?

If gardening is good, is farming even better? Many of the lifestyle factors associated with longevity – such as living in the country and getting lots of exercise – apply to farmers as well.

Some evidence suggests that farming is one of the healthiest occupations. One Australian study showed that farmers were a third less likely to suffer from a chronic illness, and 40% less likely to visit a GP than non-farm workers. Researchers from the US compared mortality rates among farmers against rates for the general population and found farmers less likely to die from cancer, heart diseases or diabetes. And studies in Sweden and France have also showed farmers are healthier than non-farmers.

Dr Masahiko Gemma of Waseda University in Tokyo studied self-employed farmers in the central province of Saitama, who were found to have a longer life expectancy that non-farmers and work later into life. Many of Gemma’s respondents were part-time farmers or retirees, and he describes many of their responsibilities as “similar to the work of maintaining a garden”.