The secret rock that could help feed the world and the ‘nerdy’ Australian scientist who discovered it


It starts with the chemistry – the pH of the rock and its taste for long-chain anionic molecules. Equally important, however, is the way it is treated. Ground in the right mix of sizes to optimize hydraulic conductivity, transpiration and gas exchange, it’s infused with billions of microbes, from 81 different species, which are encouraged to form a biofilm.

These microbes – biotechnology – are extremely expensive. The smart thing about this particular microbial soup, however, with the water retention and thermal insulation of rock, is that it only helps beneficial insects. The substrate is constantly undergoing microbial testing – but, says Hugo, “we can actually put e.coli and salmonella inside our materials, and they don’t survive.”

Time of harvest at a farm in Orlar in Da Lat, in the highlands of central Vietnam. Credit:Ngô Quang Thịnh / AFR

This means that rock (unlike vermiculite or rock wool) is not thrown away after each growth cycle but can be reused indefinitely. It also gives microbes a long and useful lifespan, which makes them very economical.

Because such a mixture of microbes generates ultra-healthy plants, no chemicals are applied and only minimal amounts of certified organic pesticides and synthetic fertilizers. No hazmat suits either – just locals in T-shirts and jeans. The thermal qualities of the rock mean that almost no heating or cooling is required – the energy consumption per kilogram is less than 1% of other intensive agriculture. Water consumption is minimal and greenhouse gas emissions are net negative. The yield, meanwhile – lettuce, edible flowers, tomatoes, strawberries, herbs – is clean, fresh, local and inexpensive.

This is important because Southeast Asia has the world’s highest rate of residue-induced cancer. Imported “clean” foods are stole in at enormous cost and enormous emissions; the poor get sick. In addition, about half of Vietnam’s food production comes from the Mekong Delta, which is gradually shipwreck due to climate change and salinizing due to the construction of hydroelectric dams upstream of the river in China and Laos.


Mekong rice uses 2,500 liters of water per kilogram; Orlar food uses only 30 liters – and with four times the income per kilogram. Plus, being vertical farming, with 20 plants grown in each two-meter-high stack or “pod”, it’s extremely space-saving.

Critically, the thermal qualities of the rock make it possible to grow temperate vegetables in “hostile” climates such as the Mekong River, providing massive climate adaptation and jobs with minimal water and soil. Plus, as a business run by women and 89% female, it transforms lives and families.

Hugo laughs at herself. “Two peri-menopausal women head for the jungle and say to each other ‘Let’s change the world’.”


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