Maize is a vital cereal crop globally and a key component of Turkey's agriculture. Sustainable practices, particularly the use of organic waste, are crucial for maintaining soil health and reducing environmental impact. Tea waste, rich in organic matter and bioactive compounds, presents a promising resource for composting and supports the circular economy. This study aimed to evaluate the effects of tea waste-based composts, prepared using different composting methods, on seedling growth and selected biochemical properties of maize. Five treatment combinations were established using tea composts enriched with various organic fertilizers, including chicken manure, vermicompost, and bat guano. The treatments were as follows: tea compost+chicken manure (TC+CM), tea compost+chicken manure+bat guano (TC+CM+BG), tea compost+bat guano (TC+BG), tea compost+bat guano+vermicompost (TC+BG+VC), and tea compost+vermicompost (TC+VC). To allow a broader evaluation of treatment effects, three local maize genotypes (G1, G2, G3) were included in the experiment. The effects of compost treatments were evaluated at the seedling stage based on key biochemical and morphological parameters. Different compost applications led to substantial differences in the biochemical and morphological characteristics of maize seedlings. The highest total phenolic content was observed in G1-TC+BG+VC; total flavonoid accumulation in G2-TC+VC and proline accumulation in G3-TC+VC; total antioxidant capacity in G2-TC+CM+BG; catalase activity in G1-TC and G3-TC+BG; ascorbate peroxidase activity in G3-TC+BG+VC; total chlorophyll in G3-TC+CM; and total carotenoid in G3-TC+BG treatments. Morphologically, the tallest seedlings were obtained in G1-TC+VC, the largest leaf area in G3-TC, and the highest fresh seedling weight in G3-TC+CM treatments. Enhanced tea compost mixtures positively influenced various biochemical and morphological traits in maize seedlings. Notably, the TC+CM, TC+VC, and TC+BG+VC treatments outperformed others across multiple parameters, demonstrating their potential to improve plant growth. These findings offer a promising pathway toward more environmentally conscious agricultural practices and reinforce the prospects of sustainable crop production.