you got any compost worms running tran?
I have some 50 litre wicked garden pots with worm towers running in them...that was my design for a pot that didn't need to be moved after harvest, continuously has fresh organic matter going through the worm tower (and the worms go spread that through). Put all the trim and mulched up stem in the worm tower as well. Just a quick green manure between grows and robert's ya father's brother. Having it wicked as well allows you to leave in unattended for up to a week. Put them in a little greenhouse that catches it's own water...or maybe a shed with lights if you are that way inclined. Never need to buy ferts or whatever, maybe add some compost from your main bin or buy a bag or two once a year - but shouldn't be necessary.