In order to preserve the health of vineyards, viticulture is heavily reliant on phytochemicals. Nevertheless, the development of eco-friendly strategies is being driven by green regulations in order to reduce their accumulation in the environment. In this regard, seaweeds have been demonstrated to be one of the marine resources with the greatest potential as plant protective agents, offering an environmentally benign alternative approach to sustainable grapevine production. The present study was conducted in vineyard located at West of the West Desert Road, Al-Qusiya city, Assiut Governorate to assessed the effectiveness of the solo or dual foliar application of magnesium sulphate and/or seaweed extract at various dosage (0.05, 0.1 and 0.2% for each one) on the yield, cluster parameters and berries physio-chemical quality of Flame Seedless grapevines throughout 2023 and 2024 seasons using randomized complete block design in ten treatments with 3 replicates. The results were summarized that applying seaweed extract was more efficacious than magnesium sulphate particularly at 0.2% followed by 0.1%. foliar spraying with 0.2% for both seaweed extract and magnesium sulphate was the most effective treatment on studied traits followed by the concentration of 0.1% for both without significant differences. Therefore, the combination of 0.1% magnesium sulphate + 0.1% seaweed extract has proven to be an effective approach for enhancing the growth, yield, and both physical and chemical quality of Flame seedless grapes in Egypt under sandy soil.