Week 1 in the Tower

My homegrown seedlings have been in the tower for one week now.  I can definitely see that they have grown,  They are supposed to start out slowly and then take off so I guess I have to wait for the exponential growth.  I have lost a tomato and spinach seedling.  I have no idea why they died.  They both just started wilting and shrived up.  Hopefully I won’t lose anymore.