CO2 is needed for healthy plants. Plants use CO2 for photosynthesis. The CO2 is absorbed through the leaves and converted into energy and oxygen. If there is not enough CO2, the plant cannot use the sun to grow. The atmosphere contains only 0.03% CO2. To improve plant growth, you can create more CO2 in your greenhouse. You can produce CO2 from a mixture of yeast, sugar and water. As yeast grows, it produces CO2.
Fill an empty soda bottle halfway with water.
Pierce the plastic bottle cap with a sharp pin.
Place a funnel into the bottle opening. Add a half cup of sugar to the water in the bottle. Swirl it to dissolve the sugar in the water.
Add a half cup of active dry yeast to the sugar-and-water mixture. Swirl the mixture so the water goes cloudy. Put the cap back on the bottle.
Place the bottle in between your plants in the greenhouse. Shake the bottle every few hours to keep the yeast in suspension. The CO2 will be at the perfect height to be absorbed by the plant leaves.
Make up several bottles and place them throughout the greenhouse.