I let them soak in water overnight, then I put them in a bucket (with drain holes and a lid) for 2 days. at this point they have tiny roots starting to come out. I then transfer them into the tray you see in the picture above. Almost immediately, the blades start growing. 2 Days inside and they look like the pic above (so, 4 days total). another 3 or 4 days outside and they are about 3" tall and ready to feed to the rabbits and chickens :)

We have not tried carrots recently, but my wife has had good success with radishes and beets this winter.