Also if you try this try to keep the mixture away from the light. Here is the measurements 1L Water, 2 Cups Sugar, 1Tsp Baking soda, 1Tsp Yeast (i used 1 and 1/2) all into a 2L Soda bottle with a hole in the lid with a piece of tubing hanging over your plants since CO2 is heavier than air it will fall onto them. Just double for bigger containers And anyone who tells you this isn't worth doing is a complete and ignorant fool