Although it's certainly true that Genesis 3 suggests thorns, thistles and other nastier parts of nature weren't around at first, which again fits the "man came first" aspect of the Genesis 2 creation story.
However, it is also important to recognize that they were brought together and redacted by an editor (or committee of editors, perhaps even spread out over time) that arranged and tweaked the stories. At the very least, it is easy to glean from the text that they are intended to form a whole "collection," with connections between the various myths. The textual evidence suggests that the connections are stronger than that.
So while it is the more common error to underappreciate the differences between the accounts, it is a less common but equally erroneous mistake to underappreciate the "unity" (of a sort) that they have.
If we assume harmony between Genesis 1:11-13 (fruits/grains) and Genesis 2:5 (bush/plants of the field) then it is clear that fruit was the chief food in the garden and agriculture came later.