My father, digging. I look down (5)
It seems our speaker has always had a careful eye on his father and grandfather, and that he's looked up to them for his entire life – even now as a grown-up.
He rooted out tall tops, buried the edge deep (12)
The speaker admires the skillfulness with which his father dug potatoes. But what do you think this is really about? Does he really just think his dad is awesome at digging potatoes, or is he admiring something deeper?
My grandfather cut more turf in a dayThan any other man on Toner's bog. (17-18)
Same question for his grandpa: does he admire the guy for his hard work, for his skill, or for both?