haha well im working on my first grow too, so basically any info i give u i have found out from fucking up. so no worries. potting soil is pretty cheap, i like to use just some basic stuff like with sand, perlite and peat moss. the sand and perlite act as drainage, and the peatmoss holds water really well. but yeah, tinfoil can burn the leaves. it concentrates the light into a harsh ray. i dont really know how else to explain it. um but anyways, theres not really too much else to say at this point. when they're little, all they really need is light and water. keep reading through this site and you will learn lots!