After a sketching roots of irises and orchids I found I rather enjoyed drawing the higgeldy piggledy tangle the roots seem to get themselves into.  Rather than concentrating on colour I wanted to focus on a more monochromatic drawing and make the roots the central part of the sketch.  I decided an onion was good subject matter for a first attempt.

Onion with roots (Allium cepa)
A4 Artists sketch paper
Pencil crayon and 2B pencil

Onion with roots (Allium cepa) close-up #1

Onion with roots (Allium cepa) close-up #2

Onion with roots (Allium cepa) close-up #3

Onion with roots (Allium cepa) close-up #4