DIY : Co2 Generator, $10.

Hi All,

I got this idea from many threads on many forums, for all types of growers.

Co2 is very expensive, yet proven to help plant growth. As little as going from normal concentration at about 300PPM, or parts per million, to 1500PPM, can significantly boost plant growth. 1500 PPM is considered optimal for MJ.

You can use dry ice, and replace it everyday. You can buy Co2 Canisters, plus a regulator and a Co2 PPM meter, automatic valves, and all the rest- not to mention sealed lights.

Or, you could give some yeast some food, and let them give you Co2 gas in return. They also give off alcohol, but it stays in the main bottle as a liquid. Eventually the yeast will die, and you will have to replace them every 10-14 days, possibly every week with Baker's yeast. They need an oxygen-free environment to work, hence the reason for the smaller bottle, as you'll see in a minute.

Here's how to build your own Co2 Generator, for about $10.00

Parts list

(1) Empty 2-liter bottle, pop bottles work best. You want it to be able to hold some pressure.

(1) Empty smaller size bottle or cup, anything water-tight will work. I'm using a 24-oz. pop bottle. You could even use a solo cup.

(1) pouch Brewer's Yeast, you can use the "highly Active" bread yeast, Beer or Champagne yeast is better. Champagne yeast is tough, but harder to find. I found it online for $0.40 for 5 grams, about the same price as the Baker's Yeast at my local grocery. Might be fun, though, to test each kind.

(1) bag sugar- just use regular refined sugar, the yeast doesn't care.

(1) length of airline tubing, 3/8ths works fine. Just get the airstone tubing in your local pet/big box store.

(1) tube of silicone sealant, I used a freebie packet, but you can get tubes for $2.00

(1) Razor knife, or a drill, or some way to make a hole for the airline tubing in the bottle caps. Doesn't need to be perfect, you just don't want to pinch the tube.

So, we have -

Empty bottles, free by-product.
Yeast- about $2.00 for 3 small pouches. You'll need more but this will get you started.
Sugar- 5 pounds for $2.50
Airline tubing- 8 feet for $1.50
Silicone sealant- $2.00
Razor Knife- $1.00 Total = $10.00 with tax.

Each "run" needs about 2 cups of sugar dissolved in 2 cups water, 2 Teaspoons of yeast dissolved in about a 1/4 cup of WARM water. Think Infant bath warm, not hot or you'll cook the yeast. You want it about 95* F. to 100*F.

Now that you have the parts assembled, make a hole in each bottle cap big enough for the airline tubing.
Measure the tubing - you want it to go 1/2 way or so into the fermentation chamber ( 2-liter pop bottle) , over to the airlock, and all the way to the bottom of the airlock (smaller pop bottle or cup). REMEMBER to leave a good amount of slack in it, to make moving it easier. If you use the small pop bottle and seal the cap as I did for an airlock, you MUST cut a small hole in the side of the bottle,to let the Co2 out, or it will be a fancy, pressurized paper weight. I simply used the pop bottle airlock to cut down on spills and such. The silicone in this case serves only to keep the tube at the bottom, right where you want it. If you use a cup just glue the tube to the bottom, with the open end facing the wall.

Run the tubing to desired depth, and seal in place with your silicone or even epoxy.
Let the sealant dry for a few hours. be sure to get a good seal, you want the Co2 to come out of the big bottle, go into the smaller water-filled container, and bubble out- while preventing oxygen from gettin back in. Also, keep the smaller air lock lower than the top of the big bottle, or you could have water siphon back into the fermention chamber. No biggie if it does, it will just let oxygen back in and kill your Co2 reactor.

Mix up your water and sugar, I just pour the water in and add sugar, don't need to have it totally dissolved. Mix 2 Teaspoon yeast with 1/4 cup tepid water, and pour it in also. Put the cap on now, of course. You can also add baking soda if you want.

Fill the other container, with the tube set at the bottom, with water.

Gently shake the bigger bottle, and check for bubbles after a few minutes. Remember the yeast have to make enough Co2 to get into the smaller container, it may take a few minutes.

If you don't see any more bubbles, give the fermentation chamber a gentle shake, and see if that does it. If not, and the yeast mixture is still new, check the seals. Pinch the hose shut, and squeez the big bottle- if you get air out of it it's not sealed properly.

Change the yeast/sugar mixture when you stop seeing bubbles.

There you go, your very own Co2 generator!
Estimates I've seen are 50 liters of Co2 over a 2 week period.
Enjoy it, your plants (and your yield) will !

first pic is the holes drilled in the caps, tubing sealed in place. Last pic is assembled and working.

Tips: Keep the main bottle dark, wrap some tape around it if you have too. Yeast like it dark.

In addition to the yeast you mixed with water, you can also just sprinkle some on the top. Both ways work fine by them selves, but better together.

You can also add a pinch of baking soda, it seems to help the reaction.

Seal the top VERY well. it's the only place for leaks to occur. Use epoxy if you have to, sometimes silicone won't do it.

ok, camera worked for 5 minutes today. Tried to get a pic of the parts list, but I'm sire you all know what sugar. yeast, bottles, silicone, and a razor knife look like.
If not, ask me in a p.m.

question for you i tried this lil aperatus i will see bubbles coming out of the small bottle right? from the air tube at the bottom? just wanted to make sure i did this right, oh a tip i used an old crown royal fifth bag the purple velvet ones to put my two liter bottle into, this should work right? you said yeast like it dark.

The co2 is generated in the big bottle...it flows into the little bottle and then escapes the bottle...the bubbling action is similar to th@ of a small caterpillar pulling on a bong now and then!

muA

Very Nice!

I'm on my first grow, my cab is 4Wx4Hx2D, six plants and I am peaking into the high 80's to 90 on the nose. Only when lights are on. I'm 4 days into flowering. I'm very interested in this! I should def benifit form this, eh? I just wanna make sure I got this.... Is this correct?

Here is an easier way. Using the same mixture you are using Future, you just don't need the second bottle or hose..... Brewing Airlock, made to release Co2 when brewing.

Those airlocks do the trick for keeping the smell down on ferminting gasses as well. Used them many times making good ol corn mash. Im sure they would work great for this application, never tried it for a growroom.