Hey Y'all, Your Waterlady, reporting from the land of bubbly. I saw that viral post claiming “carbonated water speeds up plant growth and makes plants greener than tap water.” Cute graphic. Big promise. But is it true or just fizzy fiction?
Let’s pop the cap and do a deep dive.
First, what do we mean by “carbonated water”?
There are a few flavors of fizzy:
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Seltzer: just water + CO₂.
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Club soda: water + CO₂ plus added minerals (often sodium bicarbonate, potassium sulfate).
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Sparkling mineral water: naturally mineralized at the source, sometimes with natural CO₂.
The bubbles are the same gas but the dissolved minerals vary wildly, especially sodium and bicarbonate. That matters for plants.
The viral claim—where did it come from?
Most roads lead to a small 2002 University of Colorado Boulder student experiment on Baby’s Tears plants. Six plants, 10 days: the “club soda” group grew faster and looked greener than the tap-water group. It’s often quoted; it’s not a peer-reviewed paper, but it’s the kernel that keeps getting shared. Think of it as an interesting class project, not a grand unified law of horticulture.
Can roots actually use carbon from carbonated water?
Surprisingly, yes—roots can take up dissolved inorganic carbon (CO₂/HCO₃⁻). In controlled systems (hydroponics/aeroponics), moderately boosting CO₂ in the root zone sometimes increases biomass and improves nitrate uptake. Lettuce, for example, has shown ~15–31% fresh-weight bumps when root-zone CO₂ was enriched in carefully tuned setups; another study reported ~20% more dry shoot biomass at ~1500 ppm root-zone CO₂. That’s in research systems, not windowsill pothos.
So should we all water with LaCroix now?
Hold onto your watering can. Those same root-zone CO₂ studies also show limits and trade-offs. In oriental melon, short bursts of elevated root-zone CO₂ spurred early root activity, but longer exposure inhibited root and shoot growth—likely from acidification and disrupted nitrogen metabolism. Translation: a little CO₂ at the roots can be a signal; too much, too long becomes stress.
And remember: when soils are water-logged, they naturally accumulate CO₂ and lose oxygen. Roots need oxygen to “breathe.” Dumping lots of fizzy water into dense soil can briefly push CO₂ up and O₂ down—exactly what we don’t want. Controlled greenhouse trials ≠ your fiddle-leaf fig’s pot.
The mineral catch: sodium & bicarbonate
Here’s where club soda vs. mineral water matters:
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Sodium: Many club sodas carry added sodium bicarbonate. Sodium-rich irrigation water can degrade soil structure, slow infiltration, and stress plants—especially in containers. Not great for roots.
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Alkalinity (bicarbonate/carbonate): Waters high in bicarbonate raise media pH over time. That can lock up iron and other micronutrients and is notoriously tough on acid-loving plants (think blueberries, azaleas, camellias). Greenhouse guidelines flag alkalinity as a key water-quality parameter to manage.
One extension expert put it simply about seltzer/club soda: the CO₂ itself isn’t magical; any benefit is more about the dissolved minerals and sodium can be the spoiler.
What about sparkling mineral waters?
Natural sparkling waters (our happy place at Salacious Drinks) often carry calcium, magnesium, and bicarbonate minerals plants do use. In theory, a tiny, occasional dose of a low-sodium sparkling mineral water could nudge chlorophyll production (greenness) or nitrate uptake in certain herbs/greens, similar to the hydroponic literature’s “bicarbonate/CO₂ assists nitrogen metabolism” story. But “in theory, small and rare” is very different from “make it your main irrigation.” Overdo alkalinity and you’ll nudge pH the wrong way.
The Waterlady’s verdict
Is the viral claim totally bogus? Not entirely there is a tiny study and some legit root-zone CO₂ science behind the idea. Is it a universal gardening hack? Nope. Results depend on species, soil, concentration, and the bottle you’re pouring.
If you want to experiment (and keep it plant-safe), do this:
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Pick the right bubbles
Use plain, unflavored, unsweetened sparkling water. Skip sodas with sugar or flavorings. Avoid high-sodium club sodas. If you can read a mineral label, aim for low sodium -
Let it go flat
Open it and wait an hour. Flat cuts the “oxygen displacement” moment when you douse the soil, but the minerals remain. -
Dilute
Mix 1:1 with regular water the first time. You’re chasing micronudges, not recreating a greenhouse experiment. -
Use sparingly
Think once every 3–4 weeks for a test plant (herbs/greens often show responses). Make the rest of your waterings… water. -
Know your plant’s pH preferences
Don’t try this on acid-loving species (blueberries, azaleas, gardenias). Bicarbonate-rich water nudges pH up and can trigger iron chlorosis. -
Watch for sodium sensitivity
If leaves crisp at edges or growth stalls, stop. Sodium is sneaky in pots. -
Document like a scientist
Pick two similar plants: one “fizz-fed,” one control. Measure height/leaf color weekly for a month. If your control wins, the myth is busted on your shelf.
Quick myth notes
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“Any carbonated drink works.” No. Sugar and flavors encourage microbes and mess with osmotic balance. That’s rough on plants.
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“More fizz = more growth.” Not in soil. Excess root-zone CO₂ can inhibit growth over time.
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“It’s basically fertilizer.” Minerals in some sparkling waters can complement nutrition, but they’re not a balanced fertilizer. Treat as a cameo, not a main character.
Should we pour our premium bottles on plants?
As the world’s most biased water sommelier 😇, I vote you drink the good stuff. If a bottle goes flat on the counter, sure—give your basil a thimble now and then and see if it perks up. But for routine watering, clean, still water that matches your plant’s pH needs is king. If you’re curious about matching water chemistry to your herbs (espresso-style nerding, but for basil), I’m here for it.
TL;DR
Sparkling water can occasionally give some plants a small, situational boost—mostly due to minerals and short-term root-zone CO₂ effects. But it’s not a universal growth hack, and sodium/alkalinity risks are real in containers. Treat it as a fun experiment, not your new watering routine
