Brassica question ..feeding.

[Containergardener]

I have dwarf kale in tomato/flower bucket size pots , also spare kales, my Brussels not in final pots yet and PSB not in final pots yet . Should I be feeding them, if so what with?
Also have kohl rabi (first time growing) what should I feed that with?

Thanks

[roitelet]

High nitrogen feed, nettle tea or a commercial one.

[Containergardener]

Thank you Roitelet again