The "Garden so pure" verse appears on recordings by a number of artists, but not in the one Jean Ritchie recording I found, on the album titled Songs for the Mountaintop. It's a little different from the lyrics in the Digital Tradition. Here's my transcription:

NOW IS THE COOL OF THE DAY
(Jean Ritchie)

My Lord, he said unto me,
Do you like my garden so fair?
You may live in this garden if you keep the grasses green,
And I'll return in the cool of the day.

   CHORUS
   Now is the cool of the day,
   Now is the cool of the day;
   O this earth is a garden, the garden of my Lord,
   And he walks in his garden
   In the cool of the day.


Then my Lord, he said unto me,
Do you like my pastures of green?
You may live in this garden if you will feed my lambs,
And I'll return in the cool of the day.
CHORUS

Then my Lord, he said unto me,
Do you like my garden so free?
You may live in this garden if you keep the people free,
And I'll return in the cool of the day.
CHORUS

---

Apparently, the "garden so pure" verse DOES come from Jean Ritchie. This message has my transcription from her Celebration of Life songbook.