Well, I responded to your post over in Frugal gardening forum and will add something here but first - -

Fadi, you are restating almost exactly what Colorado State University researchers found out with Hyponex. The titled it "Consumers Beware Potting Mix Choices":

"Hyponex All Purpose Potting Soil and Green Charm resulted in poor plant growth. Both of these media contain sedge peat, a fine particle material that tests to a low porosity. There simply isn't enough space within these media for the water and air that plant roots need to grow successfully."

The CSU folks were also critical of Black Gold Organic but not because of the cheap materials. I think the problem was low fertility and that is because of incomplete composting of mushroom compost if I could hazard a guess. That sort of thing has been noted elsewhere with mushroom compost.

I went from BG All-Purpose to Organic years ago and immediately noticed a drop in fertility. What I do is as soon as seedlings are tall enuf for overhead watering - I sprinkle the flats with a good dry organic fertilizer (Whitney Farms) before sprinkling with water. That seems to do the job and keep the process organic, as well.

Steve

I have used Hyponex for years with good results for house plants. ( When I can find it) However I have always mixed it 2 parts soil to 1 part cheap Walmart kitty litter. I put small rocks in the bottom of my planter and fertilize with Miracle Grow when needed. I am NOT a talented gardner, but it works for me.