How do Seeds sprout?

Seeds sprout when favourable temperature (15.38°C), enough oxygen and moisture are available. They absorb large amounts of water and swell. The moisture content of cells rises from 10 per cent to 90 per cent or more. The plant growth hormone, indole acetic acid which controls and promotes various stages of growth, sets into action the various life processes. Cells at the growing tips of the embryo within the seed divide rapidly and the primary root emerges through the soft seed coat. Further changes follow leading to emergence of the shoot Soil is not always necessary for the sprouting of seeds. Seeds will sprout in moist sand; saw dust, peat mosses, cloth or even paper if favourable conditions are available.