does anyone know if you can grow carrots in trays or module's as I noticed carrot plants [nates]where being sold in a garden centre I believe you can sow and grow Paris carrot variety in trays but I'm not sure about normal carrots transplanted ?
Root plants that immediately throw down a long taproot after germination are poor candidates for transplanting. As Yorkie has already said, unless the plants being sold were the round type of carrot they don't have a chance of doing well. I've read of folk who set carrots off in kitchen roll inners or similar, but you'd still have to plant them out at a very early stage for any guarantee of success.
The only roots that have worked in modules for me are swedes, turnips, mangels and beet (alliums too, of course.) Kohl rabi transplant well, but they're more of a swollen stem than a root.