Dormant seeds need water, oxygen and the proper temperature to begin the process of germination. Until seeds get all three of these conditions, they remain dormant and do not begin to grow.
When a seed is exposed to the proper conditions, it can begin the process of germination by taking in water and oxygen through its seed coat. The embryo inside of the seed begins to enlarge. When it reaches a sufficient size, the seed coat breaks open. A root emerges from the seed coat and then a shoot, or plumule, follows the root. The shoot contains all of the leaves and the stem of the plant. If the required conditions are met poorly, then the seed may experience poor germination and growth.