Substrate Support Interfering With Root Growth?

I started a new tank a few months ago, using ada amazonia and some uns controsoil (since I ran out of amazonia) as substrate. There have definitely been other problems (like algae) that I'm struggling with which might have an effect, but most of the plants I've added seem to have trouble with root growth in general. (I will make another thread asking for advice about the other problems once I have enough posts on here.)

The monte carlo I dry started did grow some roots but they're not that long and it's easy to pull them out. Everything else I've tried to plant either doesn't stay in the substrate, or the stems melt and the plants break off.

It didn't occur to me before, but could it be due to the plastic egg crates I have stacked underneath? I have a few layers of them since I wanted some banks and slopes. Is it possible that the plants have trouble growing roots because they can't move the substrate out of the way? Or am I thinking too much and there's another cause?

 

Well that's good to know. The monte carlo was actually doing quite well and at about 4-5 weeks, it had already filled the area I wanted it to fill. But yeah, I haven't noticed the roots getting any longer than maybe about an inch, so that's why I was thinking it might be the egg crates.