Originally Posted by SouthernGorilla
Is the soil just ordinary topsoil? The compacting problem could be solved by adding sand, perlite, or vermiculate to the soil. No terrestrial soil is comprised of just organic matter. All garden soil has clay and sand mixed in as well.
I'm going to subscribe to see how the humus works out. I was thinking about using it for our twenty-gallon but got in a hurry and went with regular dirt.
I have used one bag of Ace hardware garden soil and one bag of Ace hardware topsoil. Top soil has peat, composted forest products sand (not exceeding 10%). It also says it contains inorganic materials but does not list them. The garden soil is also made of compost/bark, sphagnum peat moss, wetting agent and slow release fertilizer. Also lists quite a number of polymer coated inorganic fertilizers.
I sieved/flooded/dried twice to hopefully remove all inorganic material. Even if some remain they are polymer coated so not very concerned.
I am aware of the inorganic fraction of soil but finding sand over here is an issue no matter how ridiculous searching for sand in a desert sounds like. It is loaded with carbonates. 20ish ml of 5% acetic acid (white distilled vinegar) added to a small amount of "agricultural sand" was enough to make it fizz for 24+ hours. So I'll probably use pool filter sand which I have some of now.
As for the clay, the nearest source of clay sand is 500+ kilometers away. Vermiculite however I do have and not looking forward for the golden flakes floating.
To be honest I am doubtful if I will notice the effects of the humus because I am changing the substrate + cap to something I have not used before. There is no way for me to attribute a positive impact on growth to solely the humus, which Im probably going to use 0.5ish kg at most. However I'll try but not in the near future.
Sorry for the long post.
Meanwhile, entertain yourself http://www.aquabotanic.com/?p=1833