I know we have had really cold weather but i thought my onions and shallots that were stringed up in the shed and greenhouse would be ok...not so..they are frozen solid

..what can i do with them now

..our cabbages at the allotment were frozen solid and weighed a ton..when they thawed out they went a funny colour and smelt a bit dodgy

..basically what i'm asking is will my onions be ok when thawed or should i forget about them...and for future hints on where to keep them..
many thanks
ftm