Thanks for the question! So let’s take a look at the sentence itself: it is difficult to grow cacti in a humid climate. What is the natural interpretation of this sentence? Well, it’s that if we’re in some kind of a humid climate, then it’s going to be hard to grow cacti there. In other words, if humid climate, then hard to grow cacti, which is
HC —> DGC
Let’s take a look at what you diagrammed.
DGC —> HC
In other words, if it’s difficult to grow cacti, then you’re in a humid environment. But is this necessarily true based on what the stimulus tells us? Not at all! There are plenty of other places where it could be difficult to grow cacti that aren’t humid. For example, the moon isn’t very humid, but good luck growing cacti there! Knowing that it’s humid will let us know that it’ll be hard to grow cacti, but we can’t conclude for sure that a place is humid just because it’s hard to grow cacti there based on the stimulus.
Hope this helps! Feel free to ask any other questions that you might have.