Mine germinated about 10 days ago in a cold greenhouse - very pleased to see them up given the cost of the seed
Ps no soaking
Never soaked either, never heated - just waited - they can take a bit of time but so well worth the wait.
I have cerinthe in my front yard that was spread by birds as it was planted in the back. The large black seeds can survive some abuse. As long as the ground is damp and not frozen those shrimp guys pop right up.
Don't worry. When the end of the summer comes they will self sow their seeds (without soaking) and you'll have plenty.They don't have to be soaked and the rain will do the job too. They tend to produce loads of seeds too, so you will never want for seeds again!
I've never soaked them in my life and save and grow them every year. Such a brilliant plant to have in the garden and the bees adore them.
I sowed some about a week ago, without soaking, and they're all popping up nicely now.