stupid question, but what does it mean? does it just refer to the color of a paper calendar or is it an expression that means something else?
It's not a stupid question. :) But it doesn't really mean anything else than that "I" have some calendars, and they happen to be green.
When does one use mina/gröna instead of min/grön?
When the word they're referencing is plural. Calenders gets mina and gröna. Calendar gets min and grön.
A-ha i got it now i had trouble understanding making two words ends with a vowel A to a plural phrase
The stress on kalendrar seems to be on the second syllable. Is this correct?
Can't listen at the moment, but the stress should indeed be on the second syllable.
"Almanackor" was not accepted. I reported this already several years ago.
Added that now.