My Father's Farthing Traditional Cache

This is my father’s farthing

And here is the bizarre thing

He gave me a haiku

To serve as the clue

He wanted it to be a well-hid cache

But I thought a haiku rather rash

He insisted, so

Look below

“Find farthing

Ferret no further than

Fogbound flora”

First to find gets this:

 Everyone else has to make do with signing the log