I presume your column of interest is column G
right click the sheet tab and click view code
in the window that comes up copy paste this EVENT CODE
Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Column <> Range("G1").Column Then Exit Sub
If Target < 0.06 Then Target = 0.06
and save the file
In column G now enter some value <.06 e.g. .03 see what happens to that cell enter more than .06 in some cell in column G. what happens?