sowing and watering?

hi folks,when i sowd my onion seed about ten days ago the compost was really damp so i didnt water then , the compost has only just started to dry out so i  lightly watered yesterday and this morning the first green shoots just poking through, is this coincidence or does the water send a signal to the seed to germinate?.are you supposed to do an initial watering after sowing? what do you do? 

I would say the trick with most seeds is to initially water enough to make sure the seed is properly hydrated (especially those with hard seed-coats) and subsequently to keep the compost just moist enough to support growth, but not so wet that mould growths are encouraged (especially for seedlings prone to damping off.)

(My onion seeds were up in 8 days, but that was in a warm kitchen.)