pull down to refresh

What is the little cut stick for to the left of the sprout?

By plain water - do you mean tap/well? Distilled? Spring water?

When you rub the leaves does the discoloration move? As in it is a powder/deposit on the leaves.

It's possible a teeny bit more Nitrogen could help, but I would not start there if it's related to what is in the water you are currently using.