I tried many different growing mediums in the past and even used insulation which worked just fine. I have found expensive medium is not always better. Sourcing thru local suppliers in your area of growing medium can be cost effective these days. This is currently what I'm using and am quite happy with it for the cost ($7.95/bag) thru a local grow shop. The price would be way cheaper if I drove the 25 miles to get it directly from the company that makes it.
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Here's some results for this cheap medium.
5 weeks old using that medium and watering only.
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Making you're own gets even cheaper if you want to go that route.