To feed a Bamboo

I have one of the big ones with lovely golden canes.   I keep it in a large container, from which it get hauled out and sawn in half every 3 years or so.    It is not ready to come out yet, but the leaves look a bit yellowy.
I have never given it a feed, but perhaps it needs some nutrients,  Advice please,  Mrs Bouquet

Bamboo is (botanically) a grass, and they are heavy nitrogen feeders when they are in the ground.

If yours is in a pot, heavy nitrogen feeding is probably not what you need, but the bamboo will need some. Use a fertilizer that gives about the same amount of K as N.