Book based on a riddle 'Earth, Water, Fire, Air...'

Question

Recently I've been re-reading books I read when I was younger, and there's one that I just cannot remember. This was about a decade or so ago, so I would have been about 10 (plus or minus a few years), which might help determine the book. I'm not sure how long it was, but I assume it wasn't more than a few hundred pages, if that.

The only thing I really remember from it is this 'riddle':

Earth, Water, Fire, Air
Met together in a garden fair
Put in a basket bound with skin
If you answer this riddle you'll never get in

Searching for that finds nothing useful (just a lot of articles for The Incredible String Band).

I vaguely remember something about a maze, and (possibly) a comment that 'the fifth element is love'. Aside from this, I don't have much to go on. Still, I figured it was worth a shot.

Answer 1

Bone Island by Christopher McPherson has those lines.

... and then finding to our delight and amazement that we
were both fans of the Incredible String Band. Floating out of the
mountains singing:

Earth water fire and air
Get together in the garden fair
Put in a basket bound with skin
If you answer this riddle you'll never begin...

I call Osburn’s at 6:45. The guy who answers the phone is gone for a long time and finally someone else picks it up. She phoned yes-

It's from 2002, 212 pages.

Is Bone Island a murder mystery? A ghost story? A post-modern wonder tale, grappling with the fundamental questions of our time? All of the above, and more. But mostly it’s a story. A story that has to be told, regardless of the consequences. An intriguing second novel from the twisted imagination of author Chris McPherson, Bone Island tells the story of a book –– a book called ‘Bone Island’ (the book within this book). When reclusive novelist Homer Knee turns up dead on the shores of his Bone Island home, the manuscript of his last novel turns up… gone. Accusations fly and suspicions abound. But when Homer’s son Larry discovers the manuscript, he uncovers a secret as well — and embarks on a journey which will test his loyalties and threaten the very fabric of his life. Along the way Larry will encounter some unusual characters: a beautiful but dangerous lawyer, a paranoid cross-dressing private eye, a cynical tattoo artist and a saintly illiterate bee-keeper — who just may be his long-lost half brother, if he exists at all… The mystery though revolves around Homer, who in death assumes the significance of both Homer Simpson and Homer the blind poet of antiquity.

Answer 2

Night Maze by Annie Dalton. Two tweens in an English manor solving a mystery of a family curse involving alchemy.

He had never entered a maze. He imagined it like the drawings in comics. Trace the right path with your finger until you find the hidden treasure or the lost child.
‘Earth, Water, Fire, Air,’ sang the small blank voice in his head. ‘Met together in a garden fair. Put in a basket bound with skin. If you answer this riddle . . .’
He was too tired. Ever since the car had crossed over the river that ran quietly through the village of soft golden stone, he had been hearing disembodied voices.