The feasibility of using sulphur powder (SP) to improve physicochemical properties and promote growth of cucumber seedlings in kitchen waste compost (KWC) was investigated using cavity trays in the greenhouse. The base substrate used consisted of KWC, peat, rice husk and perlite, in respective ratios of 15%:35%:40%:10% by volume. Treatments consisted of additions of SP at rates of 0 g (CK), 3 g (T1), 6g (T2), 12 g (T3) and 24 g (T4) per liter of the seedling substrate (SS). The investigation showed that addition of SP significantly reduced pH of SS and increased its EC values (p<0.05). The germination index (GI) of cucumber seeds was significantly enhanced with SP addition at T1 (p<0.05). However, other growth indicators (shoot and belowground growth indices) showed maximum values at T2. Levels of plant nutrients (N, P, K) and organic matter in this SS reflected a trend of uptake by seedlings in the order T2>T1>CK>T3>T4, while the levels of the growth substances in T3 and T4 were consistent with the deleterious effects of excess levels of SP. Fluorescence analysis of levels of Fusarium spp. in SS showed significant reductions in copy numbers of the fungi (p<0.05) as sulfur levels decrease in the order T4>T3>T2>T1>CK. For the SS composition used for this study, T2 gave the best results for the establishment of cucumber seedlings. Other combinations of substrate and seedlings must be evaluated to determine appropriate amounts of components to be used under specific circumstances.