The vines are grown on terraces cut into the steep hillsides of the Douro Valley; they are planted along the terraces of the greatest slopes, which translates as "vertically planted vines". The vineyard soils are schist greywacke ante-Ordovician, with some granitic formations. This soil is rich in nutrients and has useful water retention properties. Traditionally, the vines in the region are grown low, close to the ground. The single or double Guyot and unilateral and bilateral cordons are the methods most frequently used for training the vines. Trellises are not permitted for Port Wine grapes. The grapes are manually harvested once they have reached the optimum maturity according to the variety.