How to Make a Homemade CO2 Generator

Updated May 31, 2017

Carbon dioxide gas, known as CO2, can be used for enriching the growing conditions for plants. Increasing the amount of CO2 in the growing environment produces larger plants. Plants can utilise about four times the amount of CO2 found in the atmosphere. Homemade generators utilise yeast to make the carbon dioxide given to plants. Powered generators can heat up the greenhouse.

Drill a hole slightly smaller than the tubing into the bottle cap of a 2-liter bottle.

Feed the tubing through the cap about two inches into the bottle. Secure the tubing with a small amount of silicon sealant, and allow it to dry overnight.

Fill the bottle halfway with warm water and two cups of sugar. The water should be lukewarm to avoid killing the yeast.

Place the extra bottle cap on the bottle and shake it to dissolve the sugar mixture. Fill the bottle with cold water until the liquid level is an inch under the tubing.

Add one tablespoon baker’s yeast and a pinch of baking soda to the bottle.

Place the tubing into the greenhouse area. The yeast may take up to three days to produce CO2.


Adding more sugar makes the generator produce CO2 for a longer length of time, but more slowly. Adding more yeast makes the generator produce CO2 more quickly, but have a shorter life.


Injury may occur if bottle is capped and not vented.

Things You'll Need

  • 2-liter bottle with cap
  • Drill and bits
  • Aquarium line tubing
  • Silicon sealant
  • Extra bottle cap
  • Water
  • 2 cups sugar
  • 1 tablespoon baker’s yeast
  • Baking soda
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About the Author

Based out of Reno, Nev., Andrew Youngker has been writing since 2007. He writes articles for various websites, covering cooking and education. Youngker is pursuing a Bachelor of Science in biology from the University of Nevada, Reno.