what soil? some soils have time release nutrients in the soil (like miracle grow), however these can be very harsh for young seedlings, also need to bear in mind some strains are more sensitive than others etc..
yes it is possible - but usually not recommended as most people like to control what they are giving their plants according to the plants needs.
when I use soil I usually start with a light soil mix - this has enough feed to last a couple of weeks until the plant has developed a bit and then start feeding 1/4 strength working my way up to full