Think it is a little too early to be  rendering final judgement on whether a mistake was made.  Give them a few days and see what happens.  Hope you are pleasantly surprised.  

Regarding the decision as to what depth to plant them at.  Good decision making is a skill.  One thing I learned in industry many years ago was to get the input from those involved before making major decisions affecting them.  Many times,  by talking through things,  I learned why people felt the way they did about what should be done.  Even if you do not learn anything new people feel better knowing their opinion and experience is of value.   This does not mean that others make the decision.  Just get the facts and come to a consensus as to what should be done.  The best decisions are usually a team effort.  

What you learn from this could be invaluable to you in the future.  Whether you make the right decision is not nearly as important as how you go about it. 

Your relationship with your father is the important thing here.  I wish mine was still around to talk with.