Manually add CO2 to marijuana grow room

I’ve got a hydroponic system with a 1,000-watt lamp. I’d like to add some CO2. Can I just saturate the grow area with CO2 every couple of hours instead of purchasing a CO2 regulator?

You can do this, but saturating the marijuana grow room with CO2 is actually rather inefficient for your plants. Most of that CO2 will slip out of the room before the marijuana plants can make use of any of it. Setting up a regulator controlled by a ppm meter will ensure that the garden has a continuous supply of CO2 at the right concentration.

CO2 regulators might appear to be expensive, but they are worth the investment. The increase in growth rate will more than pay for the device within the first year’s crop. An automatic system is also much more convenient because it doesn’t require constant inspection from you. The amount of carbon dioxide a marijuana plant needs to thrive is not harmful to humans, per se. Still the body uses CO2 concentrations to regulate our breathing automatically. An excessive amount of CO2 might not be healthy.


I’ve been wanting to add CO2 to my grow closet for some time now and found what appears to be a viable solution. I bought a bag of this stuff called Exhale. Supposedly one bag will provide a 4x4 closet with enough CO2 for 6 mos. and costs roughly $35. I purchased mine through High Tech Garden (HTG) supply, in Michigan, but they have online shopping available.

I hung the bag from one of the top support bars; as the instructions state to keep the bag above the plants because, CO2 is heavier than oxygen. The bag come with a breather patch on the front of the bags so there was no preparation required. Now I had just transplanted into my 5 gallon buckets and mesh pots a few days prior to adding the Exhale (CO2). Twenty four hours after adding the exhale, my 12" tall plants nearly doubled in size. Granted the growth spurt was probably more related to added root space, but I was blown away.

Have a good one!

Hey Robert,

I have a 4x4x6.5 grow tent set up; I started out purchasing a 400w MH/HPS Cool Tube switchable. My first crop was so nice, I smoked for free for almost three months. The next crop I had grown wound up having downy issues, but I couldn’t tell because the variety was OG Kush and the Tricomes were very dense on the leaves, looked like they were bubbling over with them. After I harvested and cured, my lower buds had the most putrid taste and smell yo could imagine. I spent a few days researching issues and discovered I had downy issues and those are caused by poor air circulation and high humidity. I picked up a couple small fan to circulate the air. Finally I broke down adn bought a 6" inline fan/carbon filter which is capable of moving 500 cfms, but only requiring like 105 cfm. I bought one of those speed bully/dial control. B4 adding the fan/filter my room temp with lights on would never drop below 88 F, lights off around 81 F. Once I installed the ducting and everything my air temp is sticking at about 80 F, but my soil temp is between 71-73 F.
I live in a condo, so outdoor space is not available and disposing of used soil is troublesome. So I decided to try coco coire in place of soil and I ran into so many problems, that a lesser smoker would have given up. I managed to harvest one plant out of 14…total waste of time and effort. I think yellow septoria was the issue in combination with an unballanced pH.
This last crop I went back to using bag soil and made sure to thoroughly wash my buckets, wiped down the inside of my tent with bleach water to kill whatever was remaining. This whole process was very irritating and messy; which has me on the search of something that will kill teh bacterias. I was lead to ozone machines, set it in the tent and run it for 24 hours and it supposedly kills everything, even in the seams.

  1. Does the ozone create CO2, or is its only purpose to removed odors and bacteria???
  2. Ozone generators; Water in my city is fortified with not only chlorine but flouride as well. I know that leaving the water exposed to air for 24 hours removes teh chlorine, but does it remove the flouride as well? I’m tired of spending $10 a week on jugs of water. They have ozone generators for purifying water and such; will this device remove the Flouride as well?

My SS and OGK seeds arrived and I’m anxiously awaiting this crop to harvest so I can get those going…hopefully without the problems I have been experiencing.

Thanks and Have a good one!

Hey, Aaron - I’m in, beleive it or not, a 2’ x 2’ space. I am definitly going to get the Exhale on the 1st, my payday. It s the only product I can afford right now, and the science seemed sound. My first LED grow - Pro Grow 260 - and I think it is ging to work perfectly in my teeny-tiny space. Thanks for the report from the field on something I am buying in 10 days!!