http://www.durgan.org/URL/?DUARS 27 May 2010 Planting carrot seeds using the board method.
Carrot seeds are often hard to germinate for several reasons. Drying out, and temperature too high above about 28C. The board over the seeds keeps moisture present, and controls the temperature, particularly on a hot sunny day. Thinning will not be necessary, since some care is taken in placing the seeds in the traverse trenches. Watering is accomplished by can dispersal on top of the board, and allowing the water to trickle underneath. This can be checked by flipping the board for an inspection. The board will be left in place for about five days, then checked thereafter daily until germination occurs. Experience had indicated that carrots germinate under good conditions in about 11 days. The length of the row is 25 feet. The soil is almost perfect, fine and friable to about ten inches.
http://www.durgan.org/URL/?DNJHE 3 June 2020 Carrots germinated in 8 days under the board