In seedling production, it is crucial to consider the uptake of fertilisers and their benefits to the plant rather than just the amount of fertiliser given. Vermicompost (worm manure) offers numerous benefits, including promoting plant growth and regulating soil, as well as providing antioxidant effects and utilizing various waste materials in production. The aim of this study was to investigate the effects of mycorrhiza, vermicompost and fertiliser doses on cucumber seedling development. The cucumber variety Olay F1 was used in the study. This research was conducted as a field study with three replications according to the coincidence plots experimental design. The study applied different doses of vermicompost (0%, 10%, and 20%) with EC 0.5-1.00, both with and without mycorrhizae, to a 2:1 peat:perlite mixture for seedling growth. Cucumber seedlings received sufficient macro and micronutrients during their developmental period. The seedlings were uprooted at approximately 40 days of age. The height of the seedling in centimetres, the length of the hypocotyl in centimetres, the diameter of the stem in millimetres, the number of leaves, and the weight of both wet and dry leaves and roots were analysed. The results of the study showed that above ground wet and dry weights and root wet and dry weights of the seedlings increased with increasing vermicompost doses. The concentrations of nitrogen, phosphorus, potassium and magnesium in the leaves of the plants increased as the organic fertiliser mixture increased. The addition of mycorrhizae to the growing medium gave different results in the characteristics studied.