Exhale CO2 Bags — Natural Carbon Dioxide Enrichment Without the Hassle
Best for: Growers wanting to boost CO2 levels in sealed spaces without tanks, regulators, or monitoring equipment
Our thoughts
If you're running a sealed grow space and haven't tried CO2 enrichment yet, Exhale bags are a genuinely clever way to dip your toe in without spending hundreds on tanks and regulators. They do exactly what they claim — feed your plants a steady stream of natural CO2 for months on end. No electricity, no maintenance, no faff. That's the appeal.
Exhale CO2 Bags deliver continuous carbon dioxide enrichment to your indoor growing environment using a living mycelial mass inside a sealed bag. A proprietary non-fruiting mushroom strain grows on organic matter inside the bag, steadily releasing CO2 through a microporous breather patch. The result is a hands-off CO2 solution that works for up to 6 months per bag — no tanks to refill, no regulators to set, no electricity needed. Just hang it above your plants and let nature do the work.
How it compares
CO2 enrichment comes in three main flavours. Here's where Exhale sits:
-
Compressed CO2 tanks: More control, higher output potential, but you're looking at £300+ for a full system (regulator, controller, tank). Ongoing refill costs. Setup required.
-
CO2 generators (propane/gas): Powerful for large commercial spaces. Overkill for hobby growers, and you need ventilation management.
-
Exhale bags: Dead simple, zero maintenance, low cost entry point. Output sits around 500–1500 ppm depending on room size and seal. Perfect for small to medium sealed spaces (4x4 to 6x6 feet).
Bottom line: if you've got a sealed room and want to try CO2 without breaking the bank or spending hours on setup, Exhale bags are the pragmatic choice.
Usage guidance
Space size matters
Exhale Original covers roughly a 4x4 foot area (128 cubic feet) and works best for 4–6 plants. Exhale XL handles 6x6 foot spaces. The smaller your room and the better it's sealed, the more effective the bag will be. CO2 is heavier than air, so it naturally sinks toward your canopy.
Placement
Hang the bag slightly above plant height. No need for fancy positioning — just get it in the grow space. For propagation, Exhale Micro fits inside standard domes over seed trays and clones.
Ventilation strategy
CO2 enrichment only works in sealed or semi-sealed spaces. If you're running constant extraction, the CO2 gets exhausted before your plants can use it. Some growers run their extraction fan on a timer, turning it off periodically to let CO2 accumulate. Others seal the room during lights-on and vent during lights-off. Either way, you need to trap the gas for the plants to benefit.
Vegetative and flowering stages
Use Exhale bags throughout the growing cycle. Many growers report faster vegetative growth, larger canopy development, and extended production during the flowering phase.
Propagation and cloning
The Micro version is specifically designed for clone domes and seedling trays. CO2 stimulates root development in young plants, so it's a solid investment if you're raising a lot of cuttings.
What to expect
The mycelium inside the bag starts off brown or tan and gradually turns white as it colonises. That's normal — don't panic if it arrives with mixed colouring. Bags fully colonised (all white) are ready to produce immediately. You should see plants respond within days of hanging the bag.
Technical specifications
-
Original model: Covers 4x4 foot spaces, 4–6 plants, up to 6 months runtime
-
XL model: Covers 6x6 foot spaces, 6–8 plants, up to 6 months runtime
-
Micro model: Fits propagation domes and trays, 3 months runtime
-
CO2 output: Up to 1500 ppm depending on room size and seal quality; typical output raises ambient CO2 by ~500 ppm
-
Mechanism: Non-fruiting mycelium strain on organic substrate, releases CO2 24 hours daily
-
Weight (Original): 4 lbs
-
Weight (XL): 11 lbs
-
Material: Hardy plastic, puncture-resistant to prevent contamination
-
Freshness seal: Doubles as a hanger for easy deployment
-
Setup: No electricity, no regulators, no monitoring equipment required
-
Origin: USA-made, organic substrate
Who this is for
- New growers wanting to trial CO2 enrichment without major expense
- Small to medium sealed grow spaces (tents, rooms, cupboards)
- Budget-conscious growers who've ruled out compressed gas systems
- Propagation specialists raising clones and seedlings at scale
- Anyone with 4–8 plants in a controlled environment
- Growers who value simplicity and zero-maintenance solutions
Our take
Exhale bags are honest kit. They do what they say — deliver steady, natural CO2 for months — and they don't require you to become a gas engineer to make it happen. First to market with this approach, and they've earned the reputation fairly. Are they perfect? No — output varies depending on seal quality and room size, and some serious growers prefer the precision of compressed systems. But for a sealed hobby setup, they're worth the investment.
If you've been curious about what CO2 can do for your plants and don't fancy spending £300+ on a full tank system, this is a smart entry point. Good time to grab one while stock lasts.
