Over feeding will cause deficiencies.
imagine you got a big toy train set
the locos at the goods yard
it tries to pull several cars onto the main track
but another train does the same thing
further up the line
then another then another...so its all blocked to fuck
that be like the trains and the rails are the roots of an over fed plant
not all goods wagons get up the line because other wagons linked up block its way
often it the old story of (N) being to far back whilst the root is sipping way too much (P) or (K)
the point being the rails are like roots carries of stuff
and not often does (Mg).def hit plants so young...unless the water is cvrap
good luck