Whats up..

To be honest with you... Ive grown all my soil plants in miracle grow and NEVER had a problem. Always great bud. Even mixed MG potting soil with MG perlite and Scotts potting soil. That combo is working great.

Im sure the expensive soil like FF or whatever is great.. but MG gets the job done no doubt and its cheap. Ive even germinated in MG potting mix before with no burns. I also give smaller doses of nutes to them after 2 weeks and dont really worry too much about the nutes in the soil. Until I have a good reason or when the grow shop isnt so damn far away... I will continue using MG.

Also to the 5-10 plants in a 30g tub question... Im sure it can be done but its probably a better idea to get them their own pots. That way if you run into a problem then it might be isolated to a couple plants that you can easily resolve compared to having it affect all 5-10. Plus if you get a hermie or male you can chop it and not worry about the roots rotting or tangling into the other plants.

Hope my info helps and goodluck on your grow!