sedimentary rock made up of calcium and magnesium carbonate. It can be of a coarse or fine grade and even a powder. The finer the grade the faster it will act so we are only concerned with the fine grade or the powder. The powder giving almost instant results and the fine grade taking a few weeks to start to buffer the soil back up to near pH7. The ratio of calcium to magnesium is about 3:1. Most soils already contain some lime in some form but all seem to be lacking the right amount.
So you have decided to grow some 'Marijuana'. Good choice my friend but what soil are you going to use and how do you know wether it will do the job or leave you with a dead plant? There is no easy way to explain the intricate nature of soil, it is a complex mix of many additives, minerals, semi composted and composted material, microbes, bacteria and normally peat. Most soil companies like to give you a few weeks of nutrients to allow for strong growth