While the plants you mentioned are considered cool weather crops, the seeds are not.
For example beets and peas both sprout best when the soil temp is 77 degrees. It takes 5-6 days to sprout at that temp. If the temp is 41 degrees it will take 36 to 42 days to sprout.
Once they are transplant size they will withstand cooler weather better than plants such as tomatoes, the so called warm weather or summer crops.
I would guess you soil is not yet warm enough for fast germination.
you soil = your soil