Urban Myth: Blue and Yellow Don't Make Green
Let's debunk the myth about blue and yellow. There are innumerable beautiful pigment variations of these two colors that will make every green you can possibly imagine. A simple rule of color theory will help you mix the green you want: When mixing a secondary color (green) from two primaries (blue and yellow), avoid the third primary (red), which is the complement (opposite) of the secondary mixture (green).
For example, to mix bright greens use cool pigments: phthalo blue and cadmium lemon or Winsor Lemon. To mix low-intensity natural greens, use ultramarine and any warm yellow, such as New Gamboge, cadmium yellow medium or Indian yellow, which all have a hint of red that knocks the intensity down a bit.
If you still like to use tube greens occasionally, tone them down by mixing with any color that has a reddish cast, such as burnt sienna, or a touch of alizarin crimson or cadmium red.