The Rosnay vineyards are managed without chemicals, and have returned to a naturally balanced soil through the use of organic and biodynamic methods for over a decade. Of course, the yields achieved are still lower than conventional neighbours - by about 1/3 - but this is partly related to the use of minimal irrigation water. Semillon is the best example of this, where some vineyards have yielded 35 tonnes per hectare with copious application of water and fertiliser. Rosnay Semillon yields between 5 and 10 tonnes per hectare, but has minimal irrigation, no water soluble fertilisers, and no disease.

The conventional approach, in contrast, produces a soil that is bare and degraded. The vines need water soluble fertilisers and fungicides to remain healthy, and the use of herbicides results in lower soil organic matter, with the soil carbon being released to the atmosphere. The soil may become acid, which in turn mobilises the existing soil salts into the ground water. Intense rainstorms are not absorbed into the soil but run off carrying valuable topsoil with them.

Critics of organic farming argue that it is better to use no-till agriculture. Before moving back to Rosnay, Sam Statham worked as a research assistant into a no-till trial, and discovered that up to four times as much herbicide had to be applied to control the weeds, confirming the contradiction of no-till ideology. Meanwhile, it has been shown that when the soil life is not exposed to chemicals it recovers very quickly from the cultivation used judiciously in organic farming systems. Ideally, of course, organic and "no-till" should be combined in fragile soils such as Australia's.

To prove the sustainability of "Rosnay", it has been used as a site for researchers in the from the University of Sydney in the field of integrated pest management and the NSW Department of Primary Industries vineyard for their urban greenwaste mulching trial. These trials have both shown that the organic methods employed are more sustainable.