how long?

how long does it usually take for the plants to break the surface of the soil?

Depends on how they were started if the were started by using germination then they will hit quicker. If you just threw a seed in the ground then its gonna take a while.

Pre Germ 4-5 days, 13mm deep,
seed in to soil, 7-8 days, 13mm deep

Roughly that is,

I do think just dropping the seed in the soil is better, you dont have to handle at all then avoiding the risk of damaging them when you transplant.

i just threw one into soil but the other one was pre-soaked for about 12 hours and then put straight into soil