Corrected Sentence:
Leah read avidly about gardening, although she had never planted a garden herself.
Explanation of Changes:
* "One" to "a garden": "One" is a bit vague and doesn't specifically refer to a garden. Using "a garden" makes it clear what Leah hasn't planted.
* Added comma after "gardening": This clarifies the relationship between the two clauses. It shows that "although she had never planted a garden herself" is a separate clause that adds information about Leah's reading.
This revised sentence is now grammatically correct and conveys the intended meaning more effectively.