Monochromatic Tree Silhouettes

My 6th grade A day classes started their monochromatic tree silhouette paintings. They began by drawing their background grid and I told them to "place different shades and tints of your color in random places". That did NOT work with them... They acted so lost and they ended up not making enough shade changes. And many of them honestly did not know how to properly mix paint. They would dip their brush in the black, then the white, then the color itself. Then they would get upset when it came out looking like "mud". After many tears were shed, I decided to spend a day practicing monochromatic scales, something I should had done to begin with!

Also I decided for paint palettes to just use Styrofoam plates. I was blessed to find a massive amounts of washable paint palettes last semester and I used them every time my classes did painting. I will go ahead and admit it, the cleaning process with those palettes was TERRIBLE. It took SO much time and effort to wash out those things and half the time they weren't even washed properly (amongst middle school kids too- surprise, surprise). I decided to put those aside and just use plates. We just throw them away once we are finished (after we save the leftover paint of course). I know in the end I'm saving more money by reusing the plastic palettes but, to me it's not worth the headache.