Window Boxes

I deviated from the color selection in my window boxes this year.  Normally, I pick red, blue, white or yellow plants.  This year I picked pink, white and a variegated yellow/green color.  I was thinking the variegated color would be nice contrast to the pink.  The colors look good, but the plants have been slow to grow.  I have been fertilizing them every time I water and that seems to help.  Maybe by September the plants will be lush and beautiful.