The crisper drawer in my fridge has a “humidity control” feature. Basically, it’s a little lever that opens or closes a set of slots on the front of the drawer. How should I set this control, if my objective is to extend the useful storage of my fruits and vegetables? 
Heck if I know, I just leave mine set to the middle. You could go to one extreme, see if stuff rots, and if so move to the other extreme.
Mine comes with a cryptic labeling where one end of the scale has an apple and the other has a carrot. WTF?
One is intended for fruits and one for vegetables. The carrot probably increases the humidity and the apple decreases it.
Remember this mnemonic: Leaves grow high on a tree, roots down low. Leafy vegetables (lettuce, cabbage) need high humidity, root vegetables (carrots) need low humidity.
Got it?
ETA: IANABiologist but I think it has something to do with stomata. The more a food needs to aspirate, the higher the humidity needs to be. This is so that it doesn’t lose moisture to the outside air, and vice versa.
Seconded. Alton Brown says to store carrots in sand in the fridge (IIRC - but maybe that was beets, another root vegetable), but less stout stuff like lettuce needs a somewhat humid environment (again, IIRC).
Foodie questions should go in CS, by the way. I know, you are asking a factual question, but that’s where the foodies hang out.
Yes, I am aspiring to be a good one.
Ack! My crisper drawer is used to hold both apples and carrots. Guess I should pick the middle setting.
It was both, actually. He showed off the sandbox for beets, then revealed a carrot socked away there, too.
I’ve been away and missed these responses until now. Thanks!