How is "Digging" a memorable poem?

The memorability of a poem is always relative. However, what is striking about Seamus Heaney's poem, "Digging," is the way in which it analogizes the work of creating poetry with the work of potato farming.

Heaney's narrator, a writer, places himself within a generational lineage of diggers. He evokes this lineage by creating a sense of place in the first two stanzas, drawing himself near to the image of his father digging, as though the man were actually present:

Between my finger and my thumb

The squat pen rests; snug as a gun.

Under my window, a clean rasping sound

When the spade sinks into gravelly ground:

My father, digging. I look down... 

The "squat pen rests" "between [his] finger and [his] thumb" like a spade. However, this is not the comparison he draws; instead he writes, "snug as a gun." There is something uncomfortable about this simile, but also something correct. A pistol can rest snugly in one's hand, but a gun is not an item that creates comfort except for the one in control of it. There is also the contrast between the productivity of creating poetry and farms and the destructiveness imposed by a gun.

The language that Heaney uses in the following stanzas is kinesthetic:

Till his straining rump among the flowerbeds   

Bends low, comes up twenty years away   

Stooping in rhythm through potato drills   

Where he was digging. 

The coarse boot nestled on the lug, the shaft   

Against the inside knee was levered firmly. 

He rooted out tall tops, buried the bright edge deep 

To scatter new potatoes that we picked, 

Loving their cool hardness in our hands. 

The present participles "straining" and "stooping" bring past actions into the present. The man "bends low" and "comes up twenty years away" like a perennial, yet also goes through drills -- a metaphor that, again, draws one back to physical exercise as well as to the regularity of farming.

He pauses the narrative, in wonder of his father's agility, then draws back further into his ancestry:

By God, the old man could handle a spade.   

Just like his old man. 

My grandfather cut more turf in a day 

Than any other man on Toner’s bog. 

Once I carried him milk in a bottle 

Corked sloppily with paper. He straightened up 

To drink it, then fell to right away 

Nicking and slicing neatly, heaving sods 

Over his shoulder, going down and down 

For the good turf. Digging. 

Again, there is a distinction in verb tenses when Heaney's narrator evokes the memory of his grandfather drinking milk, then the memory of his tending to the farm. The latter is given an urgency that connects the grandfather's digging to that of the grandson. His grandfather wanted "the good turf," just as Heaney's narrator wants the good words. They are both digging through time and through materials.

Heaney's narrator must access mental memory to create the farms of his youth, whereas his father and grandfather created the actual farms. Heaney's narrator works with the intangible, while the older men worked with the tangible:

The cold smell of potato mould, the squelch and slap 

Of soggy peat, the curt cuts of an edge 

Through living roots awaken in my head. 

But I’ve no spade to follow men like them. 

Between my finger and my thumb 

The squat pen rests. 

I’ll dig with it.

In the last stanza, there is repetition of the first, though without the image of violence. It seems now that the speaker regards the "digging" involved in writing less as a fight and now more as an effort in patience and dedication, much like farming. He commits to the effort in the final line: "I'll dig with it [the pen]."