Google em, google em!

[budfaux]

Last week I took five tomato plants to the Japanese woman who cuts my hair, as I did the previous year. A ten minute usual lasted close to an hour.
She asked me if I knew about "em". I had no clue. "Google it, Google it!"
I left with a 64oz. container she gave me, and she said I could reproduce the contents. Her English is sometimes tough to digest, but I believe she was trying to get across this was a beneficial reproductive bacteria, I guess like how my mom used to reproduce sourdough. She couldn't stop talking about it!
After seaching... I realized she was trying to steer me toward checking out "effective microorganisms".
I haven't had the time to delve in too deep yet..watched a couple of short YouTube vids and did a quick read on some sites.
I did use the search function here and nothing came up.
I realize this is probably antiquated news to most of you T'Villians, but I'm curious as to any opinions, applications, experiences...
It seems to be a pretty deep topic. (and sorry if this has been hashed and rehashed before... I found no prior info.