A week, they look, the leaves become more green.This is my grandfather told me, a lot of people in the Chinese beer gardening, flower more vivid, grow faster.
Carbon dioxide is good for the leaves, not particularly for the roots. The yeast may be beneficial. If you do this you'd want to use a beer with a very low alcohol content. The alcohol is the only thing in the beer I can think of inherently toxic to (no good for) plants.