Originally Posted by SCMurphy
While I can demonstrate that plants can overcome an anoxic substrate, one that has decomposed to the point of being toxic is dangerous to your plants.
Are you talking about sulfur compounds? I'm just thinking you'd need a lot of organic material there in the first place to create toxic levels of these. 3" of sand and laterite, for example, without any nitrogen or carbon compounds, wouldn't be an issue, even if it was densely packed with no roots, right?