How much light? germinate in soil..

They will only require light once they have sprouted through the soil surface. Once they sprout, 18/6 light/dark is best for the entire cycle of auto flowers and photoperiod plants in vegetative growth. If it is very cold where the seeds are, you can leave the lights on their 18/6 cycle to warm the soil slightly and aid germination. Hope this helps, Organoman.

If your asking about when they will break the ground and sprout, it depends on the seed. Some can pop out in 24 hours. Some take 3-7 days.

I leave the seedling in my 24 hour veg tent. Lights never go out. That's just my personal practice and method and it works well for starting seeds, autoflowers,clones and a perpetual grow. I use a dark room so I can flower multiple planters at a time without taking up veg space. I just move them in opposite rooms after 12 hours.

They will take 24 hours-10 days to pop up through ground.