[13th_yc_acct]

You shouldn't put citrus in a vermicompost bin because the worms can't eat it (right away, at any rate). I haven't heard that you can't compost citrus in a regular compost pile however. May be people getting mixed up around different types of composting.

[Tade0]

I assume that it's just like with meat, which lowers the pH of the compost, which in turn is problematic if the plants using it later on have specific requirements in this regard.