text: This is the point in the life of a plant that is most fragile.  You can either make or break it at this point.  A seed is extremely resilient to dehydration and all manner of environmental situations.  However, once you plant and water that seed, it will emerge and is extremely vulnerable.  The root system has not developed so it needs steady water.  The seedling is not large enough to store a lot of water or nutrients.  As such, it needs conditions that will be stable until it can establich itself.  It has not developed the layers of tissue to regulated it's temperature that well and if it does not get enough water, it will die and there is no turning back.  It will not regrow, unlike a well established plant that can wilt when dry and then come back to life.