Magnesium question

I have been reading, and yes I read it a while ago but never worried about it= I know that was not smart and not asking but my plants seemed fine...well let me just ask:
would the lack of magnesium slow the growth of my plant, or verses make them ALOT bigger?

I did get some today and I see that it says to give 1 tbl spoon per gallon every 1 to 4 feedings....do I follow the directions on the packaging or is there a different feeding for my lovly ladies

can I get the positive input only!

Always follow the directions and if in unsure use less.

if one is feeding there plants and they are green then they are getting plenty of nutes.