Cooking them together is fine but storing them together is not.
After a week the onions will be rotting, and then the potatoes will be too.
I one had a shallow wicker basket that I kept potatoes and onions in. I kept noticing a smell like baby shit in the cabinet, and after looking at it the rotten onion potato sludge had seeped into the weaving of the basket. Washing it several times, I was able to get most of the smell away, but I think there was still some left over. LFMF.
Cooking them together is fine but storing them together is not.
After a week the onions will be rotting, and then the potatoes will be too.
I one had a shallow wicker basket that I kept potatoes and onions in. I kept noticing a smell like baby shit in the cabinet, and after looking at it the rotten onion potato sludge had seeped into the weaving of the basket. Washing it several times, I was able to get most of the smell away, but I think there was still some left over. LFMF.