This passage is an essay, rather than a narrative. Thus, it is not so easy to understand. Here are some clues to facilitate your understanding:

In this essay, the author not only tells us how he acquires unique pleasure from his gardening activity. He also enjoys the unusual challenge of "conflict", the satisfaction of being able to improve and "do it just right this time"; he talks about the parental instinct at work in gardening and the joy of seeing the healthy growth of plants and the success in their protection; he mentions also the moral significance, how gardening keeps reminding people of the delicate and easily ruined Earth and how the healthy growth, the orderliness and thrusting life in the garden reflect "similar movements in the gardener's own spirit". 

This is the overall structure of the essay (try to fill in the blanks based on your understanding):

I. Gardening as a way of celebrating the ______________________. (paras.1-2)

II. Reasons for keeping a garden (paras. 3-10)

A. In gardening, one has to make choices and learn by ___________________. (paras. 3-4)

B. Gardening reminds us of the ____________ and __________ of our planet. (para.5)

C. A true gardener should have a sense of _____________. (paras. 6-8)

        1. Gardening requires _________ and ________. (para.6)

        2. Gardening requires ________ and ________. (para. 7)

        3. Gardening involves learning from one's own __________. (para. 8)

D. Gardening helps character building. (paras. 9-10)

        1. The growth of plants is similar to the ________ growth of man. (para.9)

        2. Gardening entails striving as in other human activities. (para. 10)

III. Gardening enables people to stay ________ for the future. (paras. 11-12)

Think about the following questions. We'll discuss them in class.

Part I(1-2):

1. What do you know about the facts of the author's gardening?

2. What do you make of the comparison between root crops and hot dogs? 

3. Why can't he resist the temptation to plant despite the seeming unwillingness?  Why “inevitably”?

4. What do you think of the last few descriptive sentences in para. 2? 

Part I(3-10):

1. What does the author mean by saying that “conflict” sends him back to garden?

2. What's the difference between black plastic and hay mulch? Why does such difference matter? What does this say about gardening?

3. Why does the author use fertilizers sparingly? Why does he say “I'm not sure”?
   

4. How do you understand  his claim that gardening is “neurotic” and “moral”?  Do you agree? 

5. What do you make of the parent-children metaphor in para. 6? 

6. What do you think of the mother-in-law story? Why such a story?

7. Why does the author say “I garden because I must”? 

8. How do you understand “A garden is an extension of oneself”?

9. Where did gardening get Adam? What does this indicate?

10.  What is the general tone in this part? Does Arthur Miller love gardening or not? 

Part III(11-12):

1. According to the author, why is gardener a proper occupation for the father of mankind? What do you think?

2. Do you agree that mankind is a creature of self-delusion? Why do you think Arthur Miller say this? What does “self-delusion” actually mean here?