Seaweed (Ascophyllum nodosum L.) extract improved the physiology, promoted the vegetative development and yield of grapevines under arid/semiarid condition
A two-year study demonstrates that foliar application of *Ascophyllum nodosum* seaweed extract significantly improves the physiology, vegetative growth, and yield of 'Alphonse Lavallée' and 'Prima' grapevines under arid/semiarid continental climate conditions, making it a recommended precision viticulture strategy for mitigating heat and drought stress.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
Imagine the world's farms as a giant, high-stakes game of survival. For decades, farmers have tried to win this game by dousing their crops in synthetic chemicals, hoping to force plants to grow bigger and faster. But this approach is like trying to fix a leaky roof by pouring more water on it; it often leads to messy side effects like dirty soil and wasted money. Now, scientists are turning to a different playbook: "precision agriculture." Instead of brute force, this strategy uses smart, targeted tools to help plants handle the tough stuff nature throws at them, like scorching heat and drought. One of the most promising tools in this new toolkit is something called a "biostimulant." Think of these not as heavy-duty fertilizers that feed the plant, but more like a vitamin shot or a pep talk that wakes up the plant's own internal systems, helping it cope with stress and grow stronger on its own.
This is where a new study from Turkey steps in, focusing on a very specific kind of stress: the "continental climate." Picture a region with freezing winters and blistering, bone-dry summers. It's a tough neighborhood for grapevines, which usually prefer milder weather. As the planet gets hotter and drier, these extreme conditions are becoming a bigger problem for wine and grape production. The researchers wanted to see if a specific type of seaweed extract could act as a superhero cape for grapevines, helping them survive and thrive even when the sun is beating down and the soil is thirsty.
The study, conducted over two summers (2024 and 2025) in the arid, semi-arid region of Central Anatolia, Turkey, tested this idea on two popular grape varieties: 'Alphonse Lavallée' and 'Prima'. The scientists didn't just guess; they set up a controlled experiment. They took healthy, seven-year-old vines and split them into two groups. One group was the "control," receiving nothing special. The other group got a special treatment: a spray made from Ascophyllum nodosum L., a type of brown seaweed, diluted to a 0.3% concentration. This spray was applied three times during the hottest, driest part of the summer: just before the flowers bloomed, when the tiny berries were about 3mm wide, and when the grapes started to change color (a stage called véraison).
The results were like watching a plant put on a pair of sunglasses and a cooling vest. The seaweed spray seemed to help the vines manage their body temperature and water usage much better than the untreated vines. Specifically, the treated vines opened their tiny leaf pores (stomata) more effectively, allowing them to breathe and drink water more efficiently. This was crucial because, in the untreated vines, the leaves got dangerously hot—often way above the ideal 25–30°C range needed for healthy photosynthesis. The seaweed spray helped keep the leaf temperatures lower, preventing the vines from overheating.
Furthermore, the treated vines looked greener and healthier. They held onto more chlorophyll (the green pigment that captures sunlight) and grew larger, heavier leaves. It's as if the seaweed gave the vines extra energy to build bigger solar panels to catch the sun's rays. This extra energy translated into bigger growth overall. The vines that got the spray produced more wood when pruned, meaning they had stronger, more vigorous shoots.
The ultimate goal, of course, is the fruit. And here, the seaweed spray delivered. In 2025, the treated vines produced significantly more grapes per vine. For the 'Alphonse Lavallée' variety, the yield jumped by 14.7%, and for 'Prima', it went up by 14.0%. Even in 2024, where results were a bit more mixed depending on the specific grape type, the trend was generally positive. The grapes also seemed to ripen a bit better, with some treated vines showing higher sugar content in their juice, which is a key factor for making good wine or eating sweet table grapes.
The researchers concluded that this simple, natural spray is a practical and effective tool for "precision viticulture." It doesn't just force the plant to grow; it helps the plant adapt to the harsh reality of a hot, dry summer. By keeping the leaves cool, the stomata open, and the chlorophyll high, the seaweed extract acts as a shield against the stress of continental climates. While the exact molecular magic behind how the seaweed works is still being figured out, the evidence from these two years suggests that a little bit of seaweed spray could be a big help for grape growers facing a warming world. It's a reminder that sometimes, the best way to help a plant survive a heatwave is to give it a little boost from the ocean.
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