I have read again and again on website after website that should not plant carnivorous plants in regular soil and only water them with distilled water.
Typically there is no justification given or a vague reminder that these are the conditions the plant finds itself in in its natural habitat.
I am really curious and the internet fails me on this one. So how do these changes affect the plant specifically? What exactly is it that is detrimental?
Some understanding in ecology and evolutionary biology can help us find an answer. In nature most plants and animals are adapted to certain environmental conditions. These carnivorous plants are adaptations to an extreme specific ecotype (bog or wetland). These bogs are very poor in nutrients, so the plants have developed an alternative method to still get enough nutrients from the environment (hence catching flies as a source of nitrogen, instead of taking it up from the soil). They have lost the ability to get nutrients from nutrient rich soil, because they don't use that in nature. So if you now put them in nutrient rich soil, they don't know how to deal with that. This means too much nutrients will "burn" them (with burn I mean some kind of osmotic damage). This is why they recommend to give it demineralized water, because tap water still contains too much (wrong) minerals.
I hope this answers your question.
