F3

Can anyone explain what F3 means and what it is?

F3 is filial generation number 3.
Goes like this...
P1 x p2= f1 ...... P meaning parent
F1 x f1= f2
F2 x f2=f3
Etc...

Typically the higher the generation the more work was actually put into breeding the plants for specific traits. That's not always true but it's a good sign IMO.

I love to see F5,6,7+ that is what defines a good breeder from a pollen chucker . Anyone can breed an F1 or F2 and get something dank if they have something good to start with. Breeding out farther though takes thought and proper selection so that you don't get bad traits along the way. Ideally breeders will choose individual plants from thousands to get only the best traits.

Also if you take seed from a herm and breed that then take that seed etc but i feel written scientifically that would be H3 or such