Which is more valuable or necessary to you?
- that the reader be given the mechanical details
- that those details be codified in publication
Actually, I mention this one for the sake of completeness. It isn't quite pertinent here …
- that the aforementioned details be available for a reader to discover
- that someone in your story appreciates or recognizes the details
There is some overlap early in the exposition, but the optimal set of approaches for each of those are rather divergent.
reader should know
This is good for the experience of the reader, listener, or viewer because understanding something helps bind a story together. Your purpose is not to clobber them over the head with the thing, but to expose it and to make it obvious for those who are able or who wish to recognize it.
For your situation, the best method is, frankly, probably to contrive a few co-incident events.
Actually, this doesn't seem likely to be a concern for your situation — it does best with ethical, emotional, or metaphysical drama, — and so I'll explain it with the characters need to know section.
I'm probably not the only one who thinks like this: You've devised something which you think is especially clever or insightful, and you'd like to have it written and saved for the sake of posterity. Something like that.
As I stated above: I'll not discuss this here.
reader can discover
The important thing here is not that it be obvious. The reader who seeks the answer shall discover it; those who do not would not benefit were they to be given it anyways. More mystical mumbo jumbo, et cetera.
The pleasure taken by a peruser of your stories comes from discovering the detail, not from being given it. Your best way to achieve that is to drop hints, here and there — rather like the crafty crook smugly satisfied with their own work.
Works best in larger stories spanning multiple publications; it also works with interactive forms of storytelling, i.e. role-playing games or whatnot strongly in the storytelling corner of a Threefold model.
How exactly is it done, though? Well, think of the Blind Men and the Elephant parable: you know how it works, even if your characters do not.
characters need to know
Maybe they don't quite understand exactly how it works, but they do get some idea.
This is most likely to be what you need for your problem: so, this vegetation exists somewhere which is likely to be quite hot, yes? Your characters will probably need to devise something to protect themselves from the heat. All you need to do is to contrive a few fortunate happenstances whereby they discover that those same protective garments or shields also serve to weaken the vegetation, and — bingo!
The protagonists don't need to understand the details; indeed, you can have one or two of them suggest hypotheses which you would understand to be incomplete or even incorrect. This ties in with the reader can discover class: also, it features a good dosage of the unreliable narrators and all that jazz.