You're talking about M3 soil... Medical Marijuana Mix!
I just did an interview with the guys who make it for 'weed World" magazine...
Have used it-- grows really good weed, great for beginners... especially if you do as they suggest and 'top dress' the soil at transition with the "Papa's Perfect Poop" fertilizer that is part of their soil mix... and they make THAT too!
Great guys-- all med patients and VERY dedicated to the cause... they got sick of Med patients having trouble getting/growing what they needed... and wanted and easy organic option for them.
Decent folks! They are on facebook if interested.