Fruit Set in Grapevines: Complete Post-Fruit Set Nutrition Guide

Fruit Set in Grapevines: Post-Set Strategy for Productivity and Quality

The fruit set stage in grapevines is one of the most delicate phases in the Vitis vinifera production cycle. During this critical moment, fertilized flowers develop into small berries that will form the clusters. However, not all flowers turn into berries, and without proper vineyard management, significant yield losses and poor grape quality may occur.

Following fruit set, grapevines require specific nutritional support to promote berry enlargement, enhance resistance to environmental stresses, and ensure high-quality development. Effective post-set fertilization stabilizes yield and maximizes productivity, enabling growers to harvest superior quality grapes essential for premium wine production.

 

Why Is a Post-Fruit Set Nutritional Strategy Crucial?

The post-fruit set phase is decisive for both the quantity and quality of production. If the plant does not receive adequate nutrient supply, it may undergo flower and berry drop (shatter) or develop small, low-sugar berries (millerandage). To avoid these issues, consider the following:

• Balance between vegetative and productive growth: An overly vigorous vine may divert energy from the berries, while a weak plant may fail to nourish them properly.

• Increase in sugar content and aroma: Sugar levels in the grapes are key to determining the wine’s alcohol content and aromatic profile.

• Achievement of uniform, well-developed berries: Berry size affects final yield and the wine’s structure.

To maximize the vine's productive potential, a targeted strategy using specific products such as Lieta-Veg, Maral NPK, and Target Plus is essential. These help enhance cluster development and resilience to environmental stress.

 

Vineyard Management After Fruit Set: The Role of Biostimulants and Specific Fertilizers

1. Lieta-Veg: Soil Activation and Enhanced Nutrient Uptake

Among the most innovative post-fruit set fertilization products, Lieta-Veg stands out for its 100% plant-based composition, enriched with beneficial microorganisms. This bioactivator contains Bacillus amyloliquefaciens AGS282, Bacillus subtilis S3B1, and Bacillus licheniformis PS141, which provide multiple benefits to Vitis vinifera:

✔️ Boosts root activity:

• Enhances root system growth, making it deeper and more capable of exploring larger soil volumes.

• Increases uptake efficiency of essential nutrients such as phosphorus and iron, often limited in vineyard soils.

• Promotes root colonization by beneficial microbes, improving symbiosis with the rhizosphere.

✔️ Stimulates berry growth, improving cluster uniformity and size:

• Promotes better cell division during the berry enlargement phase, leading to larger, more uniform fruit.

• Increases synthesis of natural auxins and gibberellins—key hormones for cell expansion and nutrient accumulation.

• Helps improve cluster structure by reducing small, underdeveloped berries (millerandage) and enhancing uniform ripening.

📌 Application method for vines:

• Fertigation: 10–20 L/ha, applied every 15 days throughout the growing season to maintain consistent plant stimulation.

• Foliar spray: 20–30 ml/hl to enhance photosynthesis and improve stress resistance.

Lieta-Veg is a true soil activator, improving long-term fertility and providing plants with a continuous supply of nutrients. Regular vineyard use helps keep vines vigorous, productive, and more resilient to adverse weather conditions.

 

2. Maral NPK: Nutritional Balance for High-Quality Clusters

Maral NPK is a next-generation bioactivated fertilizer enriched with nitrogen, phosphorus, and potassium (6-5-5), along with zinc and organic carbon. Its innovative formula utilizes RyZea technology, based on extracts from three marine algae (Ascophyllum nodosum, Fucus spp., Laminaria spp.), ensuring complete and balanced nutrition for the vine.

✔️ Optimizes nutrient absorption and supports vine development:

• Provides a balanced NPK ratio to sustain plant growth and berry metabolism.

• Contains sulfur and zinc, essential for protein synthesis and photosynthesis.

• Supplies organic carbon, improving microbial activity in the soil and enhancing nutrient availability.

✔️ Enhances resistance to environmental and physiological stress:

• The algae in Maral NPK contain bioactive polysaccharides that help vines withstand heat and water stress.

• Elicitor compounds stimulate the vine’s natural defense mechanisms, reducing vulnerability to pathogens and adverse weather.

• Improves photosynthetic efficiency, enabling more energy for cluster development.

✔️ Improves grape quality by increasing Brix level and berry size:

• Increases Brix level by up to 10%, enhancing grape sugar content and final wine quality.

• Stimulates cell division and expansion, resulting in more homogeneous and larger clusters.

• Promotes even ripening, balancing sugars and acidity and enhancing wine aroma.

📌 Application strategy for vines:

• Foliar: 2–4 L/ha during key phases such as fruit set, berry enlargement, and veraison to maximize grape quality.

• Fertigation: 3–6 L/ha to ensure a consistent nutrient supply and balanced cluster development.

Field tests show that Maral NPK not only improves grape quality but also increases yield per hectare. Thanks to its advanced formulation, it is ideal for supporting vine productivity and enhancing the wine’s organoleptic properties.

 

3. Target Plus: Uniformity and Stress Resistance in Vines

Target Plus is an innovative bioactivator designed to enhance nutrient distribution, stress tolerance, and crop quality. Its advanced formulation is based on Laminaria spp. extracts, natural iodides, and secondary metabolites—key elements for boosting vine vitality and optimizing the post-fruit set phase.

✔️ Improves nutrient distribution and vine metabolic efficiency:

• Enhances sap circulation, optimizing nutrient transport to the clusters.

• Boosts the plant’s energy metabolism, improving fertilizer assimilation.

• Increases production of natural phytohormones like auxins and cytokinins, crucial for proper berry development.

✔️ Increases resistance to environmental stress and improves harvest quality:

• Polysaccharides and natural iodides enhance tolerance to water and heat stress.

• The bioactivating effect of Laminaria spp. helps vines overcome oxidative stress and reduces flower and fruit drop.

• The anti-stress effect results in more uniform clusters with lower incidence of shatter or millerandage.

✔️ Stimulates berry enlargement and uniform ripening:

• Improves cluster structure, ensuring more uniform berry size.

• Increases grape firmness and sugar content, enhancing Brix level and aromatic balance.

• Accelerates ripening, allowing for more homogeneous harvests with fewer differences between clusters.

📌 Specific application to vines:

• Foliar spray: 300–400 ml/hl from bud break to fruit ripening to support plant resistance and improve cluster development.

• Targeted use in wine grapes: Repeat applications during berry enlargement and veraison to reduce heat stress and enhance grape quality.

Field studies confirm that Target Plus is essential for achieving uniform berry ripening and enhancing harvest quality.

 

Conclusions: A Winning Strategy for Quality Grapes

The post-fruit set phase is decisive for achieving high-quality grapes and fine wines. A well-planned nutritional strategy using Lieta-Veg, Maral NPK, and Target Plus offers multiple advantages:

• Improved cluster development and increased berry size

• Higher sugar content and enhanced aromatic characteristics

• Greater resistance to environmental stress and vine diseases

• Long-term soil fertility optimization ensuring sustainable results

Implementing a targeted nutritional plan for grapevines means maximizing yield and grape quality—resulting in a more abundant harvest and wines with superior organoleptic properties.

 

 

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