Yellow Onion with Red/Green Palette

I decided to take on a project. Actually it's an old idea from my teacher Hong Nian Zhang at The Woodstock School of Art. He taught us three complementary palettes. (RED/GREEN, BLUE/ORANGE and YELLOW/PURPLE). I was never able to keep a predominately single color in any of my paintings like he did (I ended up using his palettes but getting a different color sense which is perfectly fine) so I'm going to concentrate on this concept and see if I can do 6 onions in each of the primary and secondary colors. Now that I've said this outloud I wonder how far I will get!
Yellow Onion with Red/Green Palette, 4x3", watercolor on board