Worthless potting soil

I was discouraged over the progress of my plants. My tobacco shoots came up the two times I planted but just stopped and did not continue growing until they finally just wilted away. Three of my Goji berry plants are growing but not very well.

But I discovered my problem. Isn't the Internet great? I was surfing and came upon this article that says most potting soil that you buy is worthless. Here I was thinking potting soil (soil you buy to put in a pot to grow things) would have the ingredients to grow plants, but apparently not.

Especially since I am growing from seed my plants have no beneficial bacteria to help them get the few nutrients there are from the soil. I believe I read somewhere that tobacco in particular needs nutrient rich soil.

because everyone forgets that they mixed the soil from a potted plant with the potting mix when they transplanted. Since the plant's soil contains microorganisms, gardeners are "innoculating" the potting mix with beneficial microorganisms.

I don't want to have a sterile, chemical fertilizer induced growth, as the resultant fruit probably would not be as nutritious as possible. I want to try the recipe for bug juice, but I have to find a source of fish meal.