Seed germination and vigor are critical for plant propagation and agricultural productivity. This review highlights the biochemical and molecular factors that influence seed germination and vigor, emphasizing the role of stored messenger RNAs (mRNAs), proteins, and metabolic pathways. Germination vigor depends on the quality of stored mRNAs and proteins, as well as the ability to synthesize new mRNAs and proteins during germination. The sulfur amino acid metabolism pathway is a key determinant of seed germination, as it influences the metabolic state of the seed and its ability to initiate development. The balance between abscisic acid (ABA) and gibberellin (GA) hormones is crucial for germination, with GA promoting germination and ABA inhibiting it. Other hormones, such as ethylene, brassinosteroids, and salicylic acid, also play roles in germination. Cellular repair mechanisms, including DNA repair and protein degradation, are essential for maintaining seed viability and germination. The maturation program can be recapitulated during germination, allowing seeds to resume metabolic activity. Posttranslational modifications, such as phosphorylation, nitrosylation, and carbonylation, regulate germination by modulating protein function. Metabolic transitions, including the shift from reserve accumulation to active metabolism, are essential for germination. The metabolism of sulfur amino acids, including methionine (Met), is central to seed germination, as it influences the synthesis of key molecules such as S-adenosylmethionine (AdoMet), glutathione (GSH), and biotin. These metabolic processes are tightly regulated and play a critical role in ensuring successful germination and seedling establishment.Seed germination and vigor are critical for plant propagation and agricultural productivity. This review highlights the biochemical and molecular factors that influence seed germination and vigor, emphasizing the role of stored messenger RNAs (mRNAs), proteins, and metabolic pathways. Germination vigor depends on the quality of stored mRNAs and proteins, as well as the ability to synthesize new mRNAs and proteins during germination. The sulfur amino acid metabolism pathway is a key determinant of seed germination, as it influences the metabolic state of the seed and its ability to initiate development. The balance between abscisic acid (ABA) and gibberellin (GA) hormones is crucial for germination, with GA promoting germination and ABA inhibiting it. Other hormones, such as ethylene, brassinosteroids, and salicylic acid, also play roles in germination. Cellular repair mechanisms, including DNA repair and protein degradation, are essential for maintaining seed viability and germination. The maturation program can be recapitulated during germination, allowing seeds to resume metabolic activity. Posttranslational modifications, such as phosphorylation, nitrosylation, and carbonylation, regulate germination by modulating protein function. Metabolic transitions, including the shift from reserve accumulation to active metabolism, are essential for germination. The metabolism of sulfur amino acids, including methionine (Met), is central to seed germination, as it influences the synthesis of key molecules such as S-adenosylmethionine (AdoMet), glutathione (GSH), and biotin. These metabolic processes are tightly regulated and play a critical role in ensuring successful germination and seedling establishment.