How to make co2 for your indoor garden with household goods.This will give your plants all the co2 they need and then some. Your plants will experience an explosion of growth. I will never grow without it. Step 1 Poke a hole into the top of your lids on water bottles. Next fill them half way with water. You could even go with just under half-full.The less you use the less chances for a spill. Step 2 Add in 1 teaspoon of sugar and yeast. Place finger over hole in lid and shake vigorously. Repeat every 5 hrs. or so for 48 hrs. Concoction will start to bubble. The bubbles you see is actually the co2 being released into the air. If not add more sugar or yeast. Always add equal amounts of both. Step 3 Place in conjunction with you growing containers. I use 20 oz bottles because they are at the correct height for dispencing co2 directly under my plants. Simply put containers in or around your garden. Watch as your plants experience accelerated growth.