I've heard a lot of bad things about fertilized soil. Cannabis doesn't do well with it. Believe it or not, miracle grow has the right amount of nutrients and you can control the dosage. The usual rule of thumb is to NOT fertilize Cannabis the first two weeks of growth. I grew a Sativa once using miracle grow and the plant turned out perfect. It almost took over my grow closet though. When it was getting close to harvest time, I flushed for two weeks. Miracle Grow isn't organic so you'll want to flush out all the excess nutrients.