You can make a decent soil with manure humus and perlite for not very much $$ although for a few $$ more you can get a bag of Fox Farm Ocean Forest and not have to worry about feeding, soil, or anything! They like a little phosphorus in flower weeks 3, 4, 5, 6. What you use for food and how much will depend on what you use for soil. Nothing in that MG you have them in now! I use Fox Farm Ocean Forest. I give them nothing until flower and then it's just 1/8 - 1/4 strength flower nutes. I use bloombastic.

See "A Beginner's Guide to Growing" in my signature for some good information that will set you on the right path. A little knowledge will make you rest easier.