Blue-green microalgae Spirulina platensis play a significant role in sustainable agriculture by improving soil fertility, crop growth, yield, and environmental quality. This study aimed to assess the efficacy of S. platensis as a germination booster in low-fertility soils. Various concentrations of Spirulina solutions (2 g/L, 4 g/L, 6 g/L, 8 g/L, and 10 g/L) were prepared, and seeds of paddy (Oryza sativa), maize (Zea mays), green gram (Vigna radiata), and cowpea (Vigna unguiculata) were pre-soaked overnight in these solutions. Fifty seeds from each crop were treated, with treatments replicated three times in a randomized block design. A non-treated control group (water alone) was included for comparison. Seed germination and the pH of the S. platensis solutions were recorded over 10 days and analysed using ANOVA (p<0.05).

Results showed that paddy seeds soaked in a 6 g/L Spirulina solution had a significantly higher germination rate (91.11%) by day 7. Maize seeds also exhibited high germination rates (>80%) in both 4 g/L and 6 g/L treatments. In contrast, pulse seeds (green gram and cowpea) showed poor germination rates (<50%) in concentrations above 6 g/L, with 100% germination observed in the control group. The poor performance of pulses may be attributed to the high pH (10.6) of the S. platensis solution. These findings suggest that S. platensis acts as a bio stimulant for cereal seed germination, though further field studies are needed to confirm these results.