insane onion question

Ok, so I dug up my onions but it looked like the weather had turned again so I have put them in the little plastic greenhouse things i have.  The shelving is mesh so i reckon the air can circulate ok.  My question is, how long do they need to dry out before I can hang them up in the shed?  Are we talking a couple of days or weeks?  I think I saw something somewhere telling you how to string them together but someone else also mentioned hanging them up in old tights!  Any comments?

Thanks, I'll keep checking them then