Hello,
I have been useing this mixture for the last ten years. It works well for me.
2 parts vermiculie (holds nutrient solution for the plant)
1 part perlite (provides oxygen for the plant roots)
1 part all purpose sand. (provides drainage and a stable medium for the plant)
I grow in 1 1/2 gal nursery pots.
Hope this helps.
I'm new here. This is my first forum I've ever joined. I'll have more to post as time goes on. I hope to learn some things as well.
Let me know if I can be of any help.

Gladstone (The Gander)