Emily uses the image of the seed to work as a metaphor for what happens when a person dies: they are buried but then grow in the garden of heaven. And she is also using the imagery of the farmer who is connected to nature as also being closest to heaven, a philosophy found in such works as Walden, and also in Russia with Tolstoy’s novels War and Peace and, especially in Anna Karenina with the character of Levin.
The poem begins with Emily counting “the seeds” which have been planted and she awaits their blooming in the “summer”. And while she is on the one hand referring to the cycle of life as an eternity of planting, growth, and harvesting, she is also talking about planting her own seeds of “faith”.
Her usage of the word “con” in the second stanza is, I believe, key to the whole poem. In one sense she is using it as a of contraction for “count”: if you say the word “count” quickly it can be heard as “con”. But the word “con” has multiple meanings. Modern readers will see this word and immediately think of a confidence game or a trick in which a victim is conned out of their money, but this definition did not appear until about 30 years after she wrote this poem so it’s unlikely she means there is any sort of trick going on.
However, Emily’s use of “con” could also mean a contract. While we assume she is speaking in the first person in stanza two, she could also be speaking from God’s point of view in that He has a contract with us mortals in that when we are “Lain so low” (when we die and are buried) we will then be “received as high” (will take our place in heaven). In fact, if we look back at stanza one and rather than assume the “I” is Emily but is actually God, then the the act of counting every seed that is “sown beneath” takes on a quality of even the smallest seed being cared for and is part of the greater plan of life in the universe.
“Con” might also be her reference to the conning of a ship. Emily often uses nautical imagery as a metaphor for the journey of life, such as in “Whether my bark went down at sea” and “On this wondrous sea – sailing silently“. And the conning of a ship is where the captain steers the ship and so she might be playing with the image of a ship ferrying the people who are “Lain so low” to the next life where they will “be received so high”.
Finally, “con” also means “to get to know; to study or learn, esp. by repetition (mental or vocal)” (OED). In this sense Emily is studying the cycle of life through the lens of her nature imagery with the “seed” and through studying and creating art she makes the connection between what she sees in nature and what she believes might happen when she dies. Yet this act of studying is unusual in that to study does not necessarily something is being taken on “faith”. If she had abundant “faith” that heaven awaits then she wouldn’t need to study the “seeds / That are sown beneath” and look for a parallel between that and her own life because she would already accept that heaven awaits.
And it is this studying she does which leads into the final stanza where she says that the “garden” (heaven) is inaccessible to a “mortal” (we can’t see heaven with our own eyes when we are alive; we have to be dead first) and so she must “Pick” the “blossom” of “faith” (the good part that tells us we will live on in an eternal afterlife) while avoiding the “Bee” (the sting of doubt). Thus she is able to “unreluctantly” “spare this summer” (give up her moral life) with the comfort that she will continue to live on only when she is able to “Pick” the “blossom” of “faith”, but when she is not able to “believe the garden” (that heaven awaits and that we will live on eternally) then she is stung with the “Bee” of doubt.
Thus in this poem she moves back and forth with a dialogue with God but also with herself about what awaits us. Are we part of an eternal cycle of life where our mortal bodies are like seeds that when planted gives bloom to our eternal soul or do we just go back into the ground and our bodies are used as nourishment for the next crop and this replenishment of nutrients is all our life will ever be. And she expresses this doubt with the subtle shifting between the possibility that part of the poem is written from God’s point of view – as if she is mulling over in her mind what He might think – with it being all from her point of view because there might not be a God because it’s just all in her mind.