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CO, Bags Work – And I’ve Got the Receipts (aka Pulse Pro Data + Chunky HSC Plant
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CO, Bags Work – And I’ve Got the Receipts (aka Pulse Pro Data + Chunky HSC Plant
Let’s talk about the thing everyone loves to hate on: self-activated CO2 bags.
You’ve seen the comments:
“They don’t work.”
“They’re a scam.”
“Just get tanks, bro.”
“Dial your grow in… bruh.”
What if I already did?
Cool story — but I grow big, healthy, properly-fed, CO2-hungry plants, and I’ve got real data, canopy shots, and Pulse Pro readings to back it up. So here’s my friendly, well-lit, and highly-ventilated rebuttal — brought to you by science and sarcasm.
Where I’m At in My Current Flower Tent:
- Beginning of week 7 of bloom
- Strain: Vanilla Cream Pie (10–11 week finish from what I’m seeing)
- Tent: Spider Farmer 4×4
- Light: 760W, running approximately 950 PPFD
- DLI: 44.5 mol/day on a 12.5/11.5 light schedule
- DLI used to be around 48, now tapering to 39 by harvest
- Temps started at 80–81°F during stretch, now gradually backing down to around 75°F air temp and 71–72°F leaf temp while maintaining VPD at 1.3–1.4
- Current temps: ~76°F, RH: ~47%
- Leaf VPD: 1.3–1.4 kPa, using a -3°F IR offset for leaf temp
- CO2 readings taken at canopy level using Pulse Pro
- This setup mirrors my previous Blueberry Cupcakes run, which also used a CO2 bag and performed extremely well. Will include comparison photos from that grow.
The CO2 Situation:
- In my earlier runs without a CO2 bag, I consistently saw CO2 levels between 300–400 ppm, and as low as 150 ppm in mid bloom. That’s with only 650–700 PPFD. Plants were surviving — not thriving.
- Open-air outdoor readings with the Pulse show ~400 ppm ambient. That’s your baseline.
- With a single self-activated CO2 bag, I consistently hold between 800–1400 ppm, even with my exhaust system running like OJ (pulling air through the canopy 95% of the time).
- The bag sits on the floor inside the tent next to the air inlet tube. The exhaust pulls air out the top opposite side of the tent, constantly moving heavy CO2 up through the canopy and out. In this environment, it works perfectly.
- In most setups, exhaust runs most of the time anyway, even with a dialed lung room — this setup is repeatable.
- At peak, I’ve seen 1800 ppm and averaged about 1400 ppm. Now that the bag is about 6 months old, I’m cruising around 850 ppm. That’s proof it’s doing something — not just leaking hope into the tent.
- With CO2 at 1200–1400 ppm, I confidently push my plants to 1100–1200 PPFD without any issues. No herms, no weird mutations — just dense stacking and plants that look like they’re at a spa.
- Yes, I’ve done tanks. I’ve been through the regulators, timers, running up to the welding supply store for expensive refills, and the stress of flatlined ppm in mid bloom. After three full runs with bags, I’ve seen zero performance difference between bags and tanks in my setup. Just way less hassle.
Extra Nerd Stuff:
- I exhaust outdoors only during the summer — winter backdrafts (up to -40°F) are brutal. In cold months, I exhaust into the lung room instead.
- During summer, I use AC Infinity window adapters to vent multiple tents cleanly out the window.
- I run my home HVAC recirculation occasionally during the winter to keep fresh air moving.
- Bonus move: in the summer when exhausting outside, I place an extra CO2 bag in the lung room near the tent intake to “pre-load” the incoming air. It works. Like, actually works.
Also, when exhausting back into the lung room, I’ve seen CO2 spike over 2000 ppm. That’s why I use a whole-house air exchange unit once a day in winter. It brings in fresh 400 ppm outdoor air and purges the stale, CO2-rich air, wanting some fresh oxygen. After an hour or two, CO2 drops significantly in the lung room and tents. Once the system is turned off everything rebounds within roughly the same timeframe of an hour or two. This proves the bags are actively contributing — not marketing fluff. People lie. Numbers don’t.
TL;DR – Friendly PSA for the Growmies:
CO2 bags work.
Not magically. Not universally. But in a well-managed room with proper airflow, they’re a solid and consistent tool.
If your environment sucks, CO₂ won’t save you.
If your grow style is off, it won’t save you.
If your plants already have deficiencies, adding CO₂ isn’t going to fix them.
You need to be a well-experienced cultivator to truly take advantage of enriched CO₂. It’s not a magic fix — it’s a performance enhancer. But if your space is dialed in? Then yeah, CO₂ will absolutely push your plants furthe
Just remember: More CO2 means you can run more light — but that also means your plants will demand more food, more water, and a closer eye on your environment and your care. You’re turning up the engine, so make sure you’ve got the fuel and support system to match.
And honestly? I still believe adding or enriching CO2 is for growers who are highly educated — people with a full understanding of their grow, their strains, and their environment. It’s a tool, not a cheat code.
Canopy Close-Up:
Here’s a look at the canopy from my last couple cultivations using CO2 bags.
The first few shots (the ones looking still mostly green) are from my current Vanilla Cream Pie run — mid to mid-late bloom with about 3–4 weeks to go. Running 850+ ppm CO2 and 950+ PPFD, and she’s just starting to fade into those beautiful purple and yellow hues. Over the next few weeks, she’ll settle into deep royal purples as we coast into harvest.
The later shots are from past cultivars run under the same dialed-in conditions, same CO2 strategy. Same story — no herms, no nonsense. Just thick flower, deep color, and strong finish.
So yeah… CO2 bags do work.
They’re just not for lazy setups or folks expecting miracles out of a $30 pouch.
Know your grow. Respect the science. Monitor your data. Trust the process.
And stop hating on the bag — it’s doing its job.
Stay lifted. Stay curious. And grow smarter.
So what are your experiences with CO2 bags?
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14 Replies
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Very nice work. Lovely to read. Are these the chemical ones or the mushroom ones?
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Mushroom my friend
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I’m so glad to hear that haha. That’s sustainable for me.
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That is awesome if you have everything dialed and you wanna push things a little further, this is a good way to do it
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It would be interesting to see a comparison with a large milk carton 2/3rd filled with sugar water and yeast.
IMO I can’t see that anybody said they don’t ‘work’, as they do produce CO2, but there are cheaper ways to do it. Are they as effective, would be interesting to see…..
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This reply was modified 1 week, 1 day ago by pl293.
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Also a comparison to how long each method produces CO2. Sugar, water and yeast is relatively cheap
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You could also just brew something consumable. Then the by product could be beer, offsetting the cost of ingredients hahaha
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Exactly now we’re being dynamic and (even more) cost effective
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Very interesting. well sub reddits claim otherwise and I keep getting down votes for saying that they work and yet nobody can prove that they don’t, but I can prove what I can measure.
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And honestly for $25 for a bag that last a good 6 to 8 months, I am not complaining in the least
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This reply was modified 1 week, 1 day ago by
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