Did you leave the tops on? Cutting them off is supposed to help because they'll carry on trying to grow and draining water from the root. I don't know how they manage to keep them firm and sell them as 'bunching' carrots at markets mind you - may be they're chilled.
I had floppy carrots once. I think it might be down to the variety because they've never done it since. It was D'Eysines Carrot from Realseeds.
But then I was surprised to read on another forum at the time because I was trying to find out why that even seasoned growers expected bendy ones and they dunked them in a bucket of water before using them. All of the bendies seemed to be early spring types not later ones, but I may be jumping to conclusions.
