Do not, repeat NOT, plant into the top of a hot bed unless you are
sure that it isn't going to get too hot.
I always allow it to heat and then turn at least once before capping
and planting - that way you don't sterilise your seeds or burn roots
off
Despite more than 30 years in my own garden and ancestral experience
before that I still occasionally accidentally sterilise seeds
Use a thermometer - a long dairy one is good for compost heaps -
lacto bacillus and seedlings thrive at similar temperatures
kathryn