Though not focused on gardening, I enjoyed a small bio secion that I used to see in one of the Home mags (don't remember which one). They had a short list of questions some of which were kinda quirky, and would include the answers as a side bar to a regular interview. Everybody interviewed got the same questions and as a reader you got used to the premise and enjoyed the wide range of responses from some big names in interior design. Questions where things like, "what peice of furniture in your home is your favorite?" or "what did you eat for breakfast?" and "what trend do you absolutely hate in interior design today?".

Don't forget the ever-popular favorite plant question.
Stealing a page from our local paper and putting a garden twist on it, how about:

Most embarrassing garden moment

Ten years from now, I'd like my garden to be...

Favorite garden book

Behind my back, my friends say my garden is. . .

People who don't know me would be surprised to know my garden is. . .

AND...
What plant do you wish you had NEVER planted.
Were any family members gardeners when you were growing up?
What have you learned from your garden that has been useful in the rest of your life?

C.L.

You answered the question in your post. If they're writers,
and you ask them to tell about themselves and their interest
in gardening, you probably won't be able to shut them up.

For a couple of years the Salt Lake Master Gardeners' newsletter, "The Garden Patch," has simply invited a member to write a bit about her/himself for "Spotlight." That freed folk up to express their own perspectives.