Who likes to drink sour, green wine? No one. That’s why Jennie Schmidt, a Maryland farmer, says raising desirable grapes requires three farmer defenses.
Raising wine grapes requires a close watch and good management. It’s my job to sell a healthy harvest of wine grapes to wineries. When wine grapes have too much shade or are heavy with dew, the grapes become susceptible to diseases like black rot and the leaves to downy mildew. Those diseases cause damage to the leave or fruit, which then slows the growth and maturity of the fruit. And that’s the kind of wine grapes wineries will not purchase.
I’m Jennie Schmidt, and I raise wine grapes in Sudlersville, Maryland. There are three defenses I use to protect the healthy growth of my wine grapes.
- Canopy management
- Scouting
- Carefully timed fungicide applications
1. Canopy Management: My First Line of Defense for Wine Grapes
From May through September, our focus is on canopy management. A grapevine canopy includes everything that grows above-ground including trunk, stems, shoots, leaves and the wine grapes. Grapes require lots of hand labor—tucking shoots into trellis wires, trimming leaves, and opening up the canopy so the wine grapes get plenty of sunlight.
Why does this matter? Grapes left in the shade become vulnerable to mildew and mold. Sunlight helps the fruit and leaves to dry out and allows clusters to ripen evenly, which reduces the chance of disease and optimizes photosynthesis. Managing the canopy is my first line of defense for raising healthy wine grapes.
2. Scouting: The Best Way We Monitor Wine Grapes
Growing wine grapes often feels like going back to high school biology. If a plant loses too many leaves or the leaves are too diseased, it can’t photosynthesize properly, and the fruit won’t ripen. Healthy leaves, good nutrition, and timely protection all feed into the quality of the harvest.
That’s why I walk my vineyards so often. I observe and take random samples throughout the vineyard, bagging grapes from different rows and checking sugar levels. Every test tells us how close the fruit is to being ready and whether adjustments in our management are needed.
3. Fungicides: An Important Tool to Protect Wine Grapes
Unlike grain crops, grapes are highly susceptible to fungal diseases like downy mildew, powdery mildew, and black rot. These infections don’t have cures—once they set in, the damage is done. That’s why we carefully defend our canopies with fungicides. Fungicides are a preventative measure.
Our first year, we learned the hard way. We applied fungicides too late in the season and lost a lot of vines to downy mildew. Now, with a vineyard consultant and a clear spray schedule, we know which products to use and when to apply them. The goal is using precise amounts to prevent the disease and protect the crop at the right time. Overapplying is ineffective and too costly.
What most people do not know is that is takes a small amount of crop protectant to do its work. When you see a sprayer out in a field or a vineyard, the tank is quite large and full of liquid. Most of that tank is full of water. The actual product, whether fungicide or insecticide, is mixed in, and only equals about 16-32 total ounces per acre.
Safety, Stewardship, and Licenses to Spray Pesticides
As a board-certified dietitian and a farmer, I see fungicide and fertilizer use through a scientific lens. Like most farmers, I’m licensed and trained to use pesticides.
The licensing process takes a few days of training followed by a test. It covers personal safety, worker safety, and how to properly follow pesticide labels. And those labels, regulated by the EPA, are incredibly detailed, spelling out exactly how, when, and why to use each product safely.
While many crop protectant products used to protect wine grapes are labeled “organic” and therefore contain natural ingredients like sulfur and copper, that doesn’t automatically make them safer than synthetic products. What matters most is choosing the right product for the right problem and applying it responsibly.
Raising Healthy, Delicious Wine Grapes
At the end of the day, raising wine grapes is no different than raising livestock or grain. You can’t plant something in the ground and expect it to thrive on its own. It takes management, care, and constant observation to make a good harvest.
From pruning in January, to hand labor all summer, to precision fungicide applications, every step we take is designed to help the vine reach its full potential. And when harvest comes, the reward isn’t just high-quality wine grapes for the winery—it’s the knowledge that we’ve stewarded the crop with great care to provide a delicious wine for drinking.
