- Sat Jul 11, 2020 5:17 am
I used to grow a whole terrarium of highland cps in aluminum trays, and did it for maybe ~3 years with no issues. Eventually the the trays started to get little white splotches of crystallization on them, but didn't seem to be dissolvable or harmed the plants in any way. Plus if you just swap out the trays every year it shouldn't be an issue (I was just lazy).
I never really took a picture of my trays, but in this pic you can see the aluminum below.
That being said, aluminum ions are toxic to plants. The oxide that forms is actually not soluble in water and probably harmless like sand, but at a low enough PH he actual aluminum ions start dissolving into the water and may harm roots. It is said online that it harms the roots ability to absorb some nutrients like phosphorous, maybe cps not being dependent on that are a bit more robust to this? But then again in practice I never had any issues. I was growing N. rajah, N. aristolochioides, bunch of helis, etc.