Actually my question is as to comparing the word to garner and to glean but Id like to give reference to the words collect and get also.
The word gerner means
Gather or collect (something, especially information or approval)
The word glean means
Obtain (information) from various sources, often with difficulty.
So what I deduce is that the word garner has a meaning that contains the word glean but broader than it.
Coppola garnered several Oscar awards for "The Godfather".
I think we cannot replace garner with glean.Because the word glean is more associated with information but I dont see any problem if we replace the word "to garner" with the words like get, gather, collect here.
On the other hand if we look at the examples given for the word "to glean" on Oxford Dictionary, I think we can swap the words without changing their meaning.
Much information is gleaned ( garnered ) from secondary sources or has been covered in more detail elsewhere by previous authors.
Most of her war information is gleaned (garnered ) from her twice-weekly phone chats with her husband.
Information was gleaned ( garnered) from operating reports dictated for the surgical procedures and available for review.
Well most examples on the word garner on Oxford Dictionary also uses the word information so this also support my conclusion.
What do you think?