High levels of carbon dioxide (C02) are bad for humans and the earth’s atmosphere, but great for marijuana plants. That’s why marijuana growers add C02 into their indoor grow rooms.
Some even attempt adding it to outdoor gardens.
But are we adding C02 the right way, so our marijuana plants grow faster and give us fatter yields?
To start with, let’s remember why C02 is so important: our marijuana plants inhale C02 and use it as fuel for photosynthesis.
In nature outdoors, there’s 387 parts per million (ppm) of C02, and it’s adequate for plants.
But in a closed-up grow room with vigorously-growing plants, your marijuana plants might use up much of the C02 during lights-on cycle…and their growth slows as the C02 levels drop.
You add C02 to your indoor grow room to make up for what your plants use, and to increase their growth and yield.
Photosynthesis is a primary driver of your marijuana plants’ metabolism and it happens only when light is streaming onto your marijuana plants, so C02 augmentation is done only during daylight hours outdoors or lights-on hours indoors, not during dark hours.
There are a lot of opinions about how you add C02 to a marijuana garden, but it’s better if we consider the actual facts…
You deliver added C02 using tank C02, fermentation/bacterial reaction C02, chemical reaction C02, C02 generators/burners that use propane or natural gas, and dry ice.
Some of these are simple methods, such as combining vinegar with baking soda, using bucket C02, a beer-making kit, a block of dry ice, or similar low-tech solutions that make it somewhat difficult to precisely control the amount of C02 that gets into the atmosphere around your plants.
Most professional cannabis growers have found that using bucket C02 and similar techniques doesn’t provide adequate C02 parts per million increases.
C02 distribution control is important in yiur marijuana grow room, but it doesn’t just involve controlling the C02 parts per million (ppm) in your marijuana growing environment.
To get the most benefits from added C02, you control, adjust, and balance grow environment temperature, light intensity, water delivery, humidity, and C02 levels so they are optimized together.
You also have to adjust the parts per million and quality of your hydroponics nutrients.
That’s because adding C02 revs up your plants so they want more water, light, and nutrients. If you give them extra C02 without also giving them optimized levels of water, light, and nutrients, the added C02 is mostly wasted.
It could even be considered detrimental to your plants, because the extra C02 increases marijuana plant metabolism, but the marijuana grower hasn’t increased all the inputs necessary to fuel the plants’ stimulated metabolism.
For ultimate C02 control, marijuana growers use tank or burner C02, and they monitor and adjust C02 parts per million using C02 monitors and ancillary regulating equipment.
They’re aiming for 1200-1600 ppm C02 during lights-on cycle, depending on the age of the plants and other conditions.
Added C02 gives you the benefit of being able to run a hotter than usual grow room, which saves money on air conditioning and other heat-handling costs.
Regular grow room optimal temperature of 74 degrees Fahrenheit can be allowed to rise to 80-85F in a C02-augmented environment.
Just what good does added C02 do for your marijuana?
Because it stimulates photosynthesis and metabolism, it creates increased growth rate, earlier maturing crops, increased potency, and heavier harvest weight…but only if you increase and balance other inputs: light intensity, water, nutrition, grow room humidity, temperature.
If you have an under-lit garden, inferior hydroponics nutrients, too-low nutrient ppm, a too-cold grow room, or you’re not providing enough water to your marijuana plants, the extra C02 could do more harm than good.
At the very least, the extra C02 is just wasted.
Adding C02 in grow rooms with marijuana strains I’m familiar with from growing under “natural” conditions without added C02, I see those same cannabis strains with extra C02 can handle 50-350 more parts per million of hydroponics nutrients than they can handle outdoors.
They also drink about 10-30% more water.
You also adjust your growing season calendar when you add C02 because your plants speed up so you can get to bloom phase earlier, and be done with bloom phase earlier, depending on how your marijuana strains respond to the extra C02.
This can give you more crops per year…meaning more pounds of fine marijuana!
I give my marijuana plants an increased base nutrients ppm, along with special additives like CarboLoad, Bud Factor X, B-52, Big Bud, Hammerhead (or Overdrive) during bloom phase…so they have B vitamins, resin gland stimulation, more energy, and extra phosphorus and potassium to go along with their C02-enhanced metabolism.
Providing this kind of full package of optimized nutrition gives your hydroponics cannabis plants the foundation they need so the added C02 is most beneficial for your marijuana.
Marijuana growers should start adding C02 when your marijuana seedlings or clones are well-rooted and into their third week of grow phase. You want the added C02 to go into the plant canopy from underneath, and stay there in the canopy as long as possible.
In a greenhouse, grow tent, indoor grow room or other enclosure you easily achieve this by adjusting your fans and venting (including adjusting their angle, pitch, aeration strength and timing), and by using small-diameter tubing to channel C02 directly into your marijuana leaf zone.
For outdoor plants, you run C02 tubing into the plant canopy and then manually control C02 distribution whenever the day is dead calm and there’s no wind to immediately remove the C02. It’s debatable whether adding C02 outdoors is worth it.
Some outdoor growers feel it is.
My C02 hardware is a C02 tank, regulator, flow rate valve, C02 sensor, automatic shutoff apparatus, and a monitor that coordinates C02 disbursement, aeration fan timing, and vent fan timing so you don’t suck the added C02 out of your marijuana garden.
For a professional rig including the equipment I just mentioned, you pay about $1100. It’s easy to use and run. The only hassle is getting the tank refilled.
My second favorite C02 for marijuana apparatus is a C02 burner, but there are problems with those units: they create heat, humidity, and safety problems, and you have to source and use propane or natural gas.
Only you can decide if these drawbacks are worth it in your marijuana garden.
Marijuana growers running small closets, grow tents, grow chambers or other small-space grows can get away with using C02 bucket systems, dry ice, and other low-tech methods, but those aren’t optimum methods.
I highly recommend tank and regulator, or C02 burner/generator, whenever you can use them.
Please remember: it’s not healthy to spend time in your marijuana grow room when C02 levels are elevated. Ambient C02 outdoors is about 387 ppm, and that’s about as much C02 as you want to breathe.
Breathing 1600 ppm C02 is not so good for you!
Adding C02 to your marijuana grow room is relatively easy, and it gives you faster-growing plants, more THC, and heavier yields.
The cost of investing in professional hydroponics marijuana C02 equipment pays itself off in a few crop cycles, and after that, you continue to get more buds faster from every crop cycle, almost for free!