New indoor grow. Help?

Alrighty, hi everyone. Im a long time outdoor grower where mother nature has taken care of everything for me, ive started my first indoor grow, a small one, 12 plants in soil under a 175w MH *security light* I also have a 150w HPS *security light* for when I flower.

My babies are around 4 inches tall now and ive never used fertilizers or nutrients before, im quite ignorant to any and all indoor grows, ive read all I can but havent found any solid "this is what yah do and how yah do it"

Can one of you enlighten me to my situation, when to add fertilizers, what kind, basically what all do I need to know to keep my babies strong and alive.

If you have any questions to the specs of my growroom feel free to ask. If it helps you help me, count me in!

Thanks A Bundle,
Derby.

Ok well remember the fert rule you can only give ur plants 1/4 of what fertilizer labels reccomend and as for when and what to feed them... NO NUTES until week 3 and on week 3 add your nitrogen based fert (blood meal is rich in nitrogen) at 1/4 strengh, mixed well into the soil. Then ur pretty much set until you flower... Just do the same except add a high phospurous fert (bat dung, or bone meal) at 1/4 strengh when u flower.

Cheers!

Also mabye you should have pre sexed ur seeds because I dont think 150w will be sufficient for 12 plants... unless your thinking of dwarfing them, check out the "HARDDON'S FIRST SOG" thread for more on that.

I plan on only getting them to about 10 inches before I flower, and if everything goes as planned I have two 400w HPS with MH conversion bulbs on the way for a larger closet im trying to set up =)
Thanks for the help Rasta.