Make hemp flowers produce seeds?

Is there a mod that will make hemp flower produce seeds on pickup from plants you planted? 

-I noticed in a recent update the only time you obtain seeds is from the first ground clutter pickup.

 

There are hooks for when plants get harvested.  Could give the player anything you choose.  Not sure if anyone has already made a plugin to do that yet.  But definitely can be done.
I'd love a guidance where that may be located. Thanks again. 
Check out the hooks 'OnGrowableGather' and 'OnGrowableGathered'.