Looking for the best way of adding CO2 to your grow tent?

adding co2 to a grow tent

Looking for the best way of adding CO2 to your grow tent?

Image result for co2 grow tent

Adding CO2 to your grow tent can be as important as a proper nutrient regime, in this blog post we cover how you can introduce CO2 to your grow and begin to increase yields.

What is CO2?

CO2, also known as Carbon Dioxide is an invisible, usually odorless gas that naturally fills our atmosphere, CO2 is as important to our plants as oxygen is to us, we breathe in oxygen and exhale CO2 whereas plants and trees use the CO2 in the atmosphere towards photosynthesis wherein oxygen is released as a byproduct. – It’s a mutually beneficial cycle, symbiosis at it’s best.

If used correctly, you can expect to double your usual harvest as CO2 is proven to increase the speed and efficiency at which your plants photosynthesize, ultimately creating more energy to better develop ‘fruits’ or buds as we know them.


CO2 is deadly

Direct inhalation of concentrated CO2 is extremely dangers and can be fatal for humans, as little as 1% concentration in the air is enough to take you out, pets aren’t invincible to CO2 poisoning either and should be kept away from your grow area.

Your grow tent / room should have a CO2-to-air ratio of around 0.15% which is a safe level but I would advise to avoid spending extended periods of time in your tent so that you can avoid breathing in the air, also keep all surrounding living areas well-sealed from your grow space.

With that out of the way, lets begin!

How Much CO2 Do I Need?

Plants can absorb and utilize up to 1500 PPM of CO2 even though air today only contains around 300 PPM, this is because during the carboniferous period millions upon millions of tonnes of carbon bearing coal was formed, resulting in a CO2 rich environment – all plants and trees across the globe evolved to use the abundant CO2 and never lost the ability.

And because of this, cannabis grows best at around 1200 PPM.

Different methods of introducting CO2 to a grow tent:

  • CO2 Bags <– Recommended for tents
  • Compressed CO2 <– Recommended for tents
  • CO2 Generator <– Recommended for most tents
  • Fermentation <– Not Recommended for tents
  • Compost <– Not Recommended for tents
  • Dry ice <– Not Recommended for tents

The best way to add CO2 to a grow tent

Firstly, If you want to know when you should start adding CO2 to your grow tent; the answer is – yesterday! Plants thrive with CO2 and introducing it as early as possible will help prepare and strengthen branches for danker & denser buds.

Introducing CO2 to your grow tent can be done in a few ways, from as little as $5 up into the thousands of dollars for professional, large turnover setups. I’ll discuss the pros and cons of both:

CO2 bags (Exhale)

best way of adding co2 to tent grow with a CO2 bags

CO2 bags are an excellent way to introduce Carbon Dioxide to a grow tent, costing on average between $10 for generic CO2 bags up to $40 for the top rated brand Exhale, Exhales’ CO2 bags typically last 9 months.

Being “self-activated”, the only thing you need to do is remove a retaining clip that will allow mycelium spores to drop into the sterilized substrate contained within the bag, place it above your plants and allow your fans to circulate around it.

From my own personal experience, I’ve found that CO2 levels in my 4′ x 4′ tent rose from 400PPM to 1350PPM after 40 days using the Exhale CO2 bags, a definite recommendation if you’re on a budget.

The only downside to using CO2 bags is that they need at least 30 days before they produce any CO2

Bottled CO2 Gas:

best way of adding co2 to tent grow with a CO2 setup

This method of generating CO2 is a little more technical but achieves brilliant results every time, perfect if you like to take data on your grows as it gives you the ability to reliably change variables.

CO2 is released using a CO2 controller and a regulator, when your CO2 levels drop below your target (I’d recommend 1000 PPM) then bursts of CO2 are released over your plants.

If you have the budget, this is a great step-up from using CO2 bags.


CO2 Generators:

best way of adding co2 to tent grow with a CO2 Generator
Titan Controls CO2 Generator

Using a CO2 generator is perfectly fine, as long as you choose a model with safety features.

A CO2 generator works by burning either a natural gas, propane or ethyl alcohol. When these gases are burned, CO2 is released, unfortunately CO2 generators don’t only give off CO2 – they produce a lot of heat, it’s practically a gas heater and this can introduce it’s own problems such as:

  • An increase of humidity inside a sealed tent
  • An significant increase in temperature
  • Carbon Monoxide can be released if enough fuel is burned
  • Storing bottles of compressed gas indoors is dangerous.


Unless you’re grow could do with a heater, a CO2 generator might actually be ideal for you, we all have different requirements.

You clearly care about your yields, have you considered adding molasses to your nutrients?

Author: tgallone

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