http://durgan.org/2017/April%202017/25%20Apil%202017%20Carrots/HTML/ 25 April 2017 Carrots.
Carrot seed is quite small and difficult to plant at an appropriate spacing. Thinning small plants is a tedious task. My method is to enclose the seed in a soft tissue ball, which makes planting easy. I only require about 200 so the task is not too onerous. Other seeding methods are to sprinkle through a device similar to a salt shaker also use seed tapes. Both have their handicaps. Planting the ball for a reasonable number is probably the most desirable method. Planting is set at about two inch spacing in a 25 foot row, which is adequate to produce single healthy not intertwined carrots.