According to the news :
Intelligence garnered from waterboarded detainees was used to track down al-Qaida leader Osama bin Laden and kill him
This is one of those awkward statements that will make any right-thinking person wrestle with the thorny question of where the word garner comes from and what exactly it means.
Garner is one of those strange verbs that lives only inside the pages of a newspaper. I don't believe that in my long and intricate life I have ever garnered anything. It's not one of those verbs that you use.
'What are you planning to do this afternoon?'
'Oh, I'm planning to garner.'
Doesn't work, does it? Even if you put in an object for the verb you still end up with:
'I was planning to garner some stamps for my collection.'
But newspapers get to use garner without an eyelid being batted. This seems unfair, why should journalists keep all the garnering to themselves? It comes, since you ask, from the French word grenier, which meant granary. The R got moved by a process that etymologists call metathesis and so we ended up with the noun garner which also meant granary.
Then the noun was changed to a verb. Just as a person can be housed or hospitalized, so grain could be garnered, or put into the garner. To garner is to granary-ize.
The metaphorical use of garner was, of bloody course, invented by Shakespeare. In every marriage guidance counsellor's favourite play Othello tells Desdemona that she is the place:
...where I have garner'd up my heart,
Where either I must live, or bear no life;
The fountain from the which my current runs,
Or else dries up...
And then kills her a few scenes later. Anyway, the OED traces garner as a rather obscure word meaning to store up, as in a granary, until the nineteenth century when it disappears. There's no sense in the dictionary of obtain, as in the news article above.
So what the hell happened? Some strange agricultural journalist with a penchant for granarizing facts?
Must be, I suppose. And it seems to have happened in about 1980. Here's a graph of the frequency of the use of the word garnered in English.
From that graph garner what you can. And remember, it has nothing to do with garnish.