By Andi Anderson
Michigan State University is leading a breakthrough in grape growing with a method called early leaf removal. This canopy technique involves removing leaves around the fruit zone 10 to 15 days before grapevine flowering.
The goal is to reduce fruit set, produce looser grape clusters, and boost grape quality.
In Michigan’s short growing season and humid weather, dense vine canopies often cause poor ripening and fungal disease.
This is especially risky for varieties like Pinot Noir and Riesling. MSU’s research shows that early leaf removal improves airflow, reduces berry crowding, and makes grapes less prone to rot and disease.
The team, led by viticulture experts Dr. Paolo Sabbatini and Dr. Joshua VanderWeide, has tested this technique since 2008 across vineyards in Michigan.
They found that this practice improves sunlight exposure, sugar levels, berry color, and overall fruit health. It also strengthens the grape skin and encourages uniform ripening—important traits for high-quality wine.
Lab studies showed that grapes treated with early leaf removal contain higher levels of beneficial flavonoids and antioxidants. This means healthier grapes that may offer added nutritional value in juice and food products.
Importantly, this method is now accepted by vineyard managers across the state. It even works well with mechanical tools, making it easier for large vineyards to adopt.
MSU’s findings have gained global recognition, with research showing similar benefits in wine regions around the world. Their guidelines recommend doing leaf removal before or during bloom and combining it with proper training and shoot positioning.
In summary, early leaf removal is more than canopy pruning—it is a smart, science-backed strategy for improving grape quality, vineyard health, and long-term sustainability. Growers using this technique see healthier vines, fewer diseases, and better harvests.
Photo Credit: michigan-state-university-msu
Categories: Michigan, Crops, Fruits and Vegetables