Canopy management is very important for a number of reasons: sanitary cleanliness of the fruit on the vines, hydric well-being of the vine during warm and dry summers and protection of the grape clusters against hot wind/temperature during summer.
The trick is to open the vines enough so that the wind can blow dry the fruit and thus avoiding spraying but not opening too much so that the sun doesn’t damage the fruit. Sounds very basic but in practice this is a very difficult job as it means combining knowledge of the vineyard site in terms of climate and wind exposure, being good at weather forecasts, understanding the vine in terms of hydric need and how many leaves the vine can handle as these are the lungs but also evaporate the internal liquid of the vine. And so too many leaves and grapes can create hydric stress during the summer in our dry July and August months.
This year we left more leaves in our lower plots (Porcaria, Chiusa Spagnola, Verzella) as the temperatures were very high compared to average in June with the summer warmth of the month July. I was afraid for sun and heat damage which eventually did damage some of the fruit in our Porcaria vineyard, although limited.
Analyzing both techniques, I prefer the tying up technique compared to leaving the vines open as it gives better ventilation and one can open more precise the leaves according to position of the clusters to the sun. The problem is a higher cost as it takes 3x the time to do this job right. The advantage is the easy movement in the vineyard before and during harvest to cut grass before picking, prepare the clusters, clean and pick the grapes.
The faster technique of not tying up gives a large canopy over and around the vine which has the advantage to cover the grape clusters but also the soil, protecting from heat. The canopy management is less precise and especially the preparation and cleaning of the clusters is difficult/impossible before harvest. The less ventilated vine also needs more attention and treatments against powdery mildew due to the density of the vegetation.