If we look at this poem from a simple narrative level, we will identify a simple story of a farmer tired after picking apples, working hard and being taking over by sleep and the dreams that are about to come. But this poem is very intense. It's dominated by the sensation of sleep; but what does this sleep mean? "This sleep of mine / Whatever sleep it is" . The sleep and winter could mean the latest stage of the speaker's life. Maybe this sleep, "just some human sleep" is associated with death.
The apples are also symbolic, representing the fruits of the hard work in the speaker's life. He still had one more barrel to fill and a few apples to pick but he is done.
For I have had too much
Of apple-picking: I am overtired
Of the greatest harvest I myself desired.
I could almost relate to this feeling of working hard for all the much wanted achievements which at a certain point become draining.
The images in this poem are so powerful. The ladder pointing to the heaven might even have biblical connotations. The smell of the apples that make the speaker drowsy reminds me of the winter nights at my grandma's house filled with the smell of baked apples on the wood stove.
