Planting Density: A Parameter Of Fundamental Importance

Planting density is determined by the spacing between rows and between individual vines. The article classifies vineyards below 3,000 vines per hectare as low density, 3,000–6,000 as medium density and more than 6,000 as high density.

High-density planting became influential from the 1990s under the French model. Greater competition was expected to limit vegetative growth, produce smaller bunches and berries, improve the skin-to-juice ratio and encourage deeper rooting. Less vigorous plants were also expected to face lower disease pressure. The article argues, however, that density cannot be evaluated in isolation: soil, climate, desired wine style, rootstock, grape variety, training system and mechanization must all be considered.

Cold sites may require lower density to achieve ripeness, while north–south row orientation on hillsides can improve photosynthetic performance and reduce spring-frost risk. In warm areas, higher density may promote sugar accumulation, while east–west orientation can reduce direct exposure during the hottest hours. Increasing aridity also makes water-stress management and adequate root development more important; wider inter-row spacing can help.

At Tenimenti d’Alessandro, high-density vineyards planted from the 2000s aged prematurely and required explanting. Their density, combined with the variable climate of the preceding decade, also produced grapes with high sugar and potential alcohol. Short, intense rain events and very high summer temperatures changed the practical requirements of soil management.

Over-the-row machines used in dense vineyards require loose soil in suitable condition, conditions that have become less dependable. Wider rows allow conventional tractors to enter and work the vineyards. Moving away from systems of approximately 8,000 vines per hectare improves soil and canopy management, increases leaf aeration, reduces humidity and phytosanitary pressure, and permits lower applications of copper and sulphur.