What is Micro?

I recently read on another thread about something called micro which apparentlly you are suppose to put in your rez before changing from grow to bloom. What is micro and is it worth looking into?

what nutes are you using?
GH's 3 parter has a grow, a bloom, and a micro, but you use all 3 in different proportions throughout your grow....
some brands have a 2 part grow/bloom and some sort of optional microbial additive.
some brands have a beneficial microbe solution you can add to any nutrient regimen.

generally, 'micro' refers to anything with beneficial microbes in it (like mycorrhizae); they aid your plant's nutrient uptake, and unless it's specified for just flower/just veg you can pretty much you them throughout your cycle...

I went and checked my grow nutrients (I'm using Ionic) to see what it said about additives. The bottle actually says all in one on it, which I imagine means I don't need micro. Thanks mellokitty