The soils at Monsanto are divided into two kinds. The northern side is made of marl, while to the south there is marl alternated with tuff.

‘Marl’ is a schistose stone of the Marne family, clay mixed with lime carbonate, which spontaneously divides in large cubes, then once it comes to the surface under the light of the sun it disintegrates into many tiny angled pieces (marly gravel) and then finally it melts with water becoming pure soil. It is found in this double form at Monsanto, both gravelly on the surface and in large blocks in depth. The surface layer is especially friable and permeable enabling the roots to go down in depth while the sub-layer in compact blocks keeps the water even in very dry years. This kind of soil is what largely gives the wine great minerality, complexity and longevity. It is no coincidence that marl is well known as being the most suitable soil  for the cultivation of Sangiovese.

On the southern side, the presence of soil is alternated by a net concentration of tuff. That is by soil mainly of clay origin, so much so that in the areas planted with Chardonnay, even today, a Pliocene past surfaces under the shape of fossils, of sandy marine sediments alternated with clay compost fish bones. This kind of soil give the wines of Monsanto a major vivacity and olfactory complexity.