mg soil sucks major but i use mg ferts and have for decades with excellent results (pics in the gallery with more coming from this year's grow). i cut what the directions call for in half and use only every 2-3 weeks and never use anything on plants for the 1st 3-4 weeks. i have used fox farms and bought expensive shit from the local grow supply shop but nothing i've used has worked as well consistantly as mg. for flowering, i use bloom or super bloom and once again, at half strength and only once every 2-3 weeks...so they only get ferted twice during each phase of the process.

btw, the above is for my outdoor grows. indoors i use a weaker strength fert like "age old organics". it's fairly expensive but perfect for indoors...for me anyway.