Abstract: The water and fertilizer coupling benefits the health growth of turf grasses and reduces the irrigation water to some extent. A pot experiment was conducted to determine the effect of addition of silicon on seed emergence and growth of tall fescue (Festuca arundinacea) under the different soil moistures. This study showed that the soil moisture ranging from 45% to 60% of field water capacity was suitable for seed emergence of tall fescue, and the minimal requirement for soil moisture was 75% of field water capacity for plant growth of tall fescue when addition of silicon was unavailable. Addition of silicon enabled seed emergence of tall fescue to become fast, that addition of silicon shortened the time of seed emergence, increased the survival seedling rate, encouraged the plant height and leaf length to grow, and increased the biomass of shoots and roots when soil moisture was 60% of field water capacity or over it. However, addition of silicon did not affect the growth of tall fescue when soil moisture was 45% of field water capacity or below it, implying that the beneficial effectiveness of addition of silicon on tall fescue growth was strongly regulated by the soil moisture environment. This study also showed that tillers per plant, height, leaf length, and total biomass of plants between +Si (addition of silicon) treatments with 60% of field water capacity and -Si (control) treatments with 75% field water capacity was not significantly different, suggesting that addition of silicon reduced the minimal requirement for soil moisture for health growth of tall fescue, and benefited the saving irrigation water.