Seed-based restoration is a promising approach to accelerate the slow natural recolonization of Zostera marina meadows. In this study, seed-based restoration was investigated through the injection of seeds into the sediment using syringes. Parallel laboratory and field experiments were conducted to examine germination success over time under both simulated and natural field conditions.A field experiment was conducted in the Kiel Fjord (Baltic Sea), next to Seebar. The experimental setup consisted of three quadrats (3x3 m) divided into 36 plots (0.5x0.5 m). Quadrat 4 was located at 54° 20' 52.10 N, 10° 09' 04.10 E, quadrat 5 at 54° 20' 52.70 N, 10° 09' 04.20 E and quadrat 6 at 54° 20' 52.30 N, 10° 09' 04.70 E. In each plot, a seed amount equivalent to the weight of either 100 or 500 Zostera marina seeds was sown, based on the average seed weight determined prior to the experiment. Seeds were collected at two sites in Laboe and Falckenstein (Kiel Fjord) in July 2023 by snorkelers and scientific divers (Laboe: 54° 24' 48.53 N, 10° 13' 29.91 E; Falckenstein: 54° 23' 31.36 N, 10° 11' 31.15 E).They were overwintered in climate cabinets in darkness at 4°C and a salinity of 32 PSU, where they rotated every 6 hours for 1 minute. Different treatment combinations were tested, involving the factors Sowing Method (syringe (100 ml) with agar medium or Hand-Sown), Sowing Depth (2 cm or 4 cm), Origin of Seeds (Falckenstein or Laboe), and Seed density (100 or 500 seeds per plot). The Hand-Sown method served as a control. To this end, a small trench with 2-4 cm depth was manually dug using a finger. Seeds were sown into the trench, which was then gently filled with sediment from both sides. For the syringe treatment, seeds were injected into the sediment embedded in an agar medium prepared by cooking Baltic Sea water with 1.8% agar (Agar-Agar, BioScience Grade, pulv., Carl Roth). Each syringe contained 90 ml of crumbly agar, 10 g of autoclaved sediment, 100 or 500 seeds and depending on the treatment either 1 g charcoal powder or nutrients (P and N) were added. For the nutrients, according to the Redfield ratio N:P = 16:1, 100 μL of nitrogen and 10 μL of phosphorus were used per 90 mL of agar. Each syringe contained 100 or 500 seeds and included either the addition of nutrients (P and N) or charcoal powder or no further additions.The seeds were sown by scientific divers on March 12, 14 and 18, 2024 and seedlings were counted on April 23, 2024 and May 23, 2024 to determine the germination rate and evaluate which sowing method was the most successful.