What soil to use to make MTS

[Devon6209]

I am wondering what soil to use to make MTS. i have the other stuff to make it just not the actual soil. what should i use?
1. plain dirt
2. Scotts Premium Topsoil - http://www.walmart.com/ip/Scotts-Premium-Topsoil/16904039 it has peat in it tho.
3. Country Soil Topsoil - http://www.ruralking.com/top-soil-npl-40.html
4. Garden Pro topsoil - http://www.lowes.com/pd_210540-7913...L=?Ns=p_product_qty_sales_dollar|1&facetInfo=
5. Greensmix Topsoi - http://www.lowes.com/pd_210540-8258...L=?Ns=p_product_qty_sales_dollar|1&facetInfo=

which would be best?

 

[jetajockey]

I just use the cheapest stuff at lowes/hd. It's usually like 2 bucks or less a bag. The important thing is to make sure there's no fertilizers in it (like little white foam ball looking things, for example), and that it doesn't have a bunch of peat mixed in or anything. Just plain regular old topsoil, no additives, no nothing.

 

[boadams87]

Just get organic. It doesn't have anything.

 

[BillD]

Plain dirt will likely be the quickest to demineralize. The whole purpose of demineralizing is to turn topsoil into "plain dirt". The less organic matter to begin with, the quicker the process. I often dig down to the subsoil to avoid the organic matter.