In a wooden crate/garden mushrooms started growing in it without spores?

Spores exist. I recall a year ago to make mushrooms just fill a bag with cardboard and make that moist and put some mushrooms inside of the plastic bag.
Then put that quietly away in a cool spot with no air movement. Then after 3 day put several slits in the bag.
Leave that one week and you will have a full time supply of mushrooms.
for a long time