Most people assume that if a harmful chemical is truly dangerous, the first ones to ring the alarm would be governments or regulators.
But in Napa Valley — one of the most influential wine regions in the world — the opposite happened.
Winemakers moved first. Regulators lagged behind.
This week, Napa Green — a prominent sustainability certification programme in California — announced that all 101 of its certified vineyards have stopped using Roundup. Not “reduced.” Not “phased down.” Stopped.
They didn’t drop glyphosate because a law forced them to. They dropped it because consumers kept asking one simple question:
“Do you use Roundup?”
That question became so common in tasting rooms that it shifted an entire industry.
So what does it say when some of the most profitable vineyards in the world — businesses with every incentive to keep costs low — decide the cheapest weedkiller on the market is no longer worth the reputational, environmental, or health risk?
Let’s look a little closer.
Why Napa’s Sustainability Standards Finally Turned Against Roundup
For years, Napa Green allowed the use of glyphosate — and they openly admitted why. Banning it too soon, they said, would scare wineries away.
That’s the part that sounds uncomfortably familiar, doesn’t it? When an industry grows dependent on a chemical, even the sustainability programmes bend around it.
But eventually that bending has limits. As lawsuits mounted, independent research grew louder, and public awareness sharpened, the pressure shifted. Napa’s vineyards began to realise that one of the biggest threats to their brand wasn’t pests, drought, or climate change.
It was Roundup.
Anna Brittain, Napa Green’s executive director, put it plainly:
“We reached a critical point where members said the main question they get is, ‘Do you use Roundup?’”
This wasn’t activism or regulatory pressure. It was market reality. Consumers didn’t want Roundup in their wine — and the growers listened.
What Glyphosate Does to Vineyard Soil — In Napa and New Zealand
Ben Mackie, Napa Green’s vineyard programme manager, made a comment that stopped me mid-sentence:
“You’re applying Roundup directly under your super-high-value crop. It’s killing the bacteria in the soil. You’re turning it into a moonscape.”
That’s not coming from activists — it’s coming from people whose livelihood depends on soil health.
And it raises an uncomfortable question for us here in New Zealand:
If Roundup is doing that to the world’s most prized vineyard soils…
what is it doing under our own vines?
We use it widely. From Hawke’s Bay to Marlborough to Central Otago, vineyard rows are often stripped bare by herbicides. It’s considered normal. Efficient. Standard practice.
But what if “normal” is unintentionally undermining the very thing New Zealand wine is famous for — terroir, soil expression, environmental stewardship? What happens to that story if the soil beneath the vines is slowly losing life?
And once you start asking those questions, others follow naturally:
- What is Roundup doing beneath our vineyards, orchards, paddocks, school grounds, riverbanks, sports fields, and home gardens?
- How many of our “clean green” landscapes are actually herbicide-burnt strips we simply stopped noticing?
If Napa’s winemakers can see the problem clearly enough to walk away from Roundup entirely…
maybe it’s time we asked why our own vineyards are still leaning on it.
What Happened When Vineyards Replaced Roundup With Natural Weed Control
At Chimney Rock Winery, winemaker Elizabeth Vianna didn’t wait for 2026. She swapped sprayers for:
- mechanical weeders
- cover crops
- and even a flock of weed-eating sheep
And here’s the twist: not only did these alternatives work — her soil got healthier.
Sensors showed that the sheep-grazed blocks had the most biological life. Mechanically managed areas improved water retention. Everything pointed in the same direction: when Roundup goes, soil recovers.
This is what we rarely hear in public debates about glyphosate:
the short-term convenience comes at the cost of long-term soil resilience.
Vianna put it simply:
“You might save a little money year on year, but what’s your long-term vision for your vineyard?”
Healthier soil might double the productive life of vines — a massive economic advantage. What looks “cheap” now may be extremely expensive over time.
Why Leading Wineries Chose to Go Glyphosate-Free Early
At Antinori Napa Valley — part of a 600-year-old winemaking legacy — the move away from glyphosate was already underway.
For Chief Operating Officer Juan Muñoz-Oca, this wasn’t about marketing. It was about ethics, family history, and lived experience.
As a child, he watched workers applying glyphosate in Argentina while wearing hazmat suits. His father insisted on showering immediately after coming home. Those memories stayed with him.
“We know this is the right thing for us, for our community, for our wines.”
And when people closest to the chemical begin questioning it, shouldn’t regulators pause and ask why?
Why Councils Still Use Roundup When Vineyards Are Moving On
This is where Napa’s story intersects directly with our own.
In New Zealand, many councils and contractors still insist that glyphosate-based weedkillers are essential — the cheapest, fastest, easiest tools they have.
Yet every year, we see:
- more evidence of soil harm
- more questions about human exposure
- more international lawsuits
- more farmers and contractors reporting health impacts
- more communities asking councils to stop spraying near schools, parks, and waterways
And still, the message from regulators remains static:
“Glyphosate is safe when used as directed.”
Even as vineyards in one of the world’s most prestigious wine regions quietly conclude the opposite.
The Global Shift Away From Glyphosate Has Already Begun
Napa Green isn’t stopping at Roundup.
They’re planning to phase out all synthetic herbicides by 2027.
Not every vineyard will find that easy. Some may walk away from the certification altogether. But one thing Mackie said stuck with me:
“Once people adopt sustainable practices, they don’t tend to go back.”
That’s the moment behaviour change becomes cultural change.
And once you’ve seen a vineyard alive with cover crops, sheep, birds, and thriving soil… it’s hard to unsee it.
What New Zealand Can Learn From Napa’s Move Away From Roundup
Napa’s story isn’t just about wine.
It’s about a broader turning point — one that New Zealand can’t ignore forever.
Here’s what we can take from it:
- When people ask questions, industries listen.
- Soil health is becoming the new measure of sustainability.
- Alternatives exist — and once used, they often outperform expectations.
- The real long-term cost isn’t switching away from glyphosate — it’s staying dependent on it.
Most importantly, Napa shows us something simple but powerful:
Removing glyphosate isn’t radical. It’s already happening — voluntarily — in places where soil health, brand reputation, and long-term economic value actually matter.
If one of the world’s most prestigious wine regions can take Roundup out of its vineyards…
why can’t New Zealand take it out of our food system, public spaces, and water?
Resources & References
Before we wrap up, it’s worth grounding this conversation in the wider body of evidence. Napa’s decision didn’t emerge from a vacuum. It reflects years of research, debate, residue testing, and soil science that all point in the same direction: glyphosate leaves a much larger footprint than most people realise.
If we’re going to talk honestly about what’s happening beneath our vines, in our soils, and across our food system, these are the kinds of studies and reviews we can’t afford to ignore.
The Fate of Glyphosate in Soil and Water: A Review
A scientific overview of how glyphosate behaves once sprayed — including persistence, movement through soil, and breakdown pathways. Useful for understanding why vineyard soils may show long-term changes after repeated applications.
https://www.researchgate.net/publication/357480242_The_Fate_of_Glyphosate_in_Soil_and_Water_A_Review
Environmental and Health Effects of the Herbicide Glyphosate (Van Bruggen et al., 2018)
A widely cited peer-reviewed review covering glyphosate’s documented impacts on soil organisms, plants, microbial communities, and potential human health effects.
https://pubmed.ncbi.nlm.nih.gov/29117584/
Critical Review of the Effects of Glyphosate Exposure to the Environment and Humans through the Food Supply Chain (Torretta et al., 2018)
A comprehensive examination of glyphosate residues detected in food crops worldwide and the implications for chronic low-level human exposure.
https://www.mdpi.com/2071-1050/10/4/950
Glyphosate-Based Herbicides and Their Potential Impact on Microbiota: A Review of Recent Evidence (Muñoz et al., 2025)
A recent scientific review highlighting how glyphosate-based herbicides alter microbial life — including the bacteria and fungi critical for healthy vineyard soils.
https://www.mdpi.com/2305-6304/13/7/551
Leaching of Glyphosate and AMPA under Two Soil Conditions (Landry et al., 2005)
Shows that glyphosate and its metabolite AMPA can move through soil and into groundwater under certain conditions, challenging the claim that glyphosate “binds tightly and stays put.”
https://pubmed.ncbi.nlm.nih.gov/15950343/
Exposure Risk and Environmental Impacts of Glyphosate and Glyphosate-Based Herbicides (Gandhi et al., 2021)
A global review documenting widespread environmental contamination of soils, waterways, and food systems with glyphosate residues.
https://www.sciencedirect.com/science/article/pii/S2667010021001281
Why Napa Green’s Glyphosate Ban Matters
Background information on the internal discussions and industry concerns that led Napa vineyards to phase out Roundup entirely.
https://napagreen.org/news/why-napa-greens-glyphosate-ban-is-such-a-big-deal/
Taken together, these sources paint a consistent picture — not of a chemical that disappears harmlessly after use, but of one that lingers, accumulates, and influences ecosystems in ways we’re only beginning to understand.
Napa moved because its growers couldn’t unsee what the science, the soil, and their own customers were telling them. The real question now is whether we’re ready to look just as closely at what’s happening here at home.
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