Christina Websell wrote:
Just worth adding that the main reason for sowing thinly is to avoid, as
far as possible, having to thin the plants subsequently. This is because
the strong scent of carrot foilage will increase during thinning, thus
attracting the dreaded Carrot Fly.

But I find carrot seeds so small that they are impossible to sow thinly. I
considering trying to make myself one of those "seed tapes" by using
tweezers at home, but haven't followed up the idea.

I've been told it's helpful to mix the seeds with sand before sowing.