Fermented Vegetables for Dogs: Our Free Recipe

Fermented vegetables for dogs are shredded raw vegetables broken down by lactic acid bacteria over about seven days, then fed by the spoonful as a topper. Fermentation pre-digests the vegetable, lowers the compounds that block mineral absorption, and delivers live bacteria into the bowl as food rather than as a capsule. You need vegetables, a live culture, a mason jar, and a week of patience. Below is the exact recipe we make at home, the reason ours uses a culture instead of salt, and the fixes for the three things that go wrong: an overflowing jar, a cracked jar, and a white film on top.

A jar of fermented vegetables gives a dog live lactic acid bacteria plus the whole vegetable those bacteria have already started breaking down, which is something no powder can copy.

The first time I made these, I stood in my kitchen with three mason jars and no idea whether I was making something good for Milka or something I would have to throw away. Nobody in my life was fermenting vegetables for a dog. Years later it is a routine I do without thinking, and the jar in my fridge is the cheapest, most boring, most useful thing in Milka's daily bowl.

Here is what I would tell you before you start: this is not a fix for a sick dog. It is a small daily practice for a dog who is already doing well, and its value shows up over years rather than weeks. If that is what you are building, read on.

Why ferment vegetables instead of feeding them raw or cooked?

Raw vegetables are hard work for a dog. The nutrients sit inside cell walls a dog's digestive system is not built to dismantle, which is why so much of a raw carrot arrives at the other end looking a lot like a raw carrot.

Fermentation does that dismantling before the bowl, which is what turns a vegetable into a natural probiotic for dogs in food form rather than powder form. Lactic acid bacteria feed on the sugars and starches in the vegetables and produce lactic acid, which is what acidifies the jar and preserves the contents. In doing that work, they also break apart the compounds that lock minerals away. A 2023 review in Life found that fermenting vegetables reduces tannins and phytates, the two compounds that otherwise bind minerals such as iron and zinc, and raises antioxidant potential as polyphenols are released from those complexes.

Cabbage specifically responds well. A 2024 study fermenting kale with a mixed lactic culture measured total polyphenols and sulforaphane availability going up, while oxalate fell by roughly half and tannins fell by more than half. Same plant family, same base as our recipe.

And here is the part I find most useful: fermentation does not raise everything. A 2022 paper in Scientific Reports found vitamin C and phenol levels fell in several fermented vegetables compared to their raw versions, while vitamin A and carotene rose in fermented carrots and peppers. So the honest version of this claim is narrower than what you will read elsewhere. Fermenting improves mineral availability and adds live bacteria. It is not a universal nutrient multiplier.

What does the research actually show?

Most of the evidence for fermented vegetables comes from human and food science research, and I would rather say that plainly than dress it up.

There is one canine feeding trial worth knowing about. In 2019, researchers publishing in Animals fed fifteen adult beagles a probiotic strain isolated from kimchi over fourteen days. Serum triglycerides and fecal ammonia went down, HDL cholesterol went up, and fecal lactic acid bacteria counts rose with the higher dose. Fifteen dogs, two weeks, one isolated strain rather than a whole fermented vegetable, so it is a small signal rather than a settled finding. It is also the only canine trial I could find that connects fermented vegetable bacteria to dogs directly.

On the human side, a trial published in the European Journal of Nutrition found lacto-fermented vegetables eaten with a meal increased iron absorption in human subjects, though zinc absorption did not change.

There is also a finding about vegetables generally that has stayed with me. A 2005 case-control study in JAVMA looked at 92 Scottish Terriers with bladder cancer against 83 controls. Dogs eating any vegetable at least three times a week had significantly lower odds of that cancer, with the strongest association for yellow-orange and dark leafy types. Vitamin supplements showed no significant effect. One high-risk breed, owner questionnaires, association rather than cause. But the contrast between the food and the pill is the reason I keep vegetables in the routine instead of reaching for another bottle.

Which vegetables can I ferment for dogs, and which do I skip?

Those last two rows need a longer answer, because most of the internet has this backwards.

Onion, leek and chives stay out. They carry high levels of the sulfur compounds that oxidise canine red blood cells, and there are documented cases of dogs developing Heinz body anemia after eating them, including a case report of two dogs poisoned by leftover Catalan spring onions. That one is not a debate.

Garlic is a completely different conversation, and here is what most pet parents are never told. Nearly every warning you have read traces back to a single study from 2000 at Hokkaido University, published in the American Journal of Veterinary Research. Four dogs were given garlic extract equal to 5 grams of whole garlic per kilogram of body weight, by stomach tube, every single day for seven days. For a 20kg dog, that is roughly twenty cloves a day for a week. The researchers found oxidative changes in the red blood cells, and reported that no dog developed hemolytic anemia. Their closing recommendation was to keep garlic out of dog food, and that sentence got repeated for the next twenty-five years while the dose it came from quietly disappeared from the retelling.

What has been published since is more useful than that. A 12-week safety study in beagles gave aged garlic extract at up to 90 mg per kilogram daily and found no adverse effects at all: no changes in bloodwork, and no Heinz bodies or eccentrocytes on the blood smears. A 2025 study went the other way, though it is worth naming the evidence tier: it was in vitro, meaning dog blood in a test tube rather than a living dog. It found all garlic forms caused some red cell damage, with dried and granulated garlic worse than fresh. Read together, those two say the same thing from opposite directions. Form and amount decide everything. A little fresh garlic and a spoonful of concentrated powder are not the same input.

So where does that leave the jar? Garlic is optional here. If you use it, use fresh rather than dried or granulated, use a small amount, and know how much went into the batch, because a spoonful from a fermented jar is not a measured dose and that is the genuine problem with putting any potent herb into a ferment. You should also know that reference works including the Merck Veterinary Manual still advise avoiding garlic for dogs altogether. I read the dose data differently, and I would rather hand you both positions and the actual numbers than tell you what to think.

One thing you may have read elsewhere, including in write-ups of this very recipe: skip carrots for a yeasty dog because carrots are high in sugar. I have stopped saying that, because the reasoning does not hold. The bacteria in the jar consume much of that sugar during fermentation, and the yeast that causes most skin trouble in dogs is not living on the sugar in a spoonful of vegetables. If your dog is currently struggling with yeast, a lower-starch mix is a reasonable conservative starting point while you watch closely, and your dog's own response tells you far more than a vegetable's sugar content does.

How do I make fermented vegetables for dogs?

This is how to make fermented vegetables for dogs the way we do it at home. It makes about three mason jars, which we call the fermented veggies in this house because nobody has time for the long version.

You need: a food processor or a box grater, three wide-mouth mason jars, a juicer for the celery, about 500ml of celery juice, a quarter teaspoon of a live pre and probiotic powder, and a pile of shredded vegetables. Red cabbage, white cabbage and carrots are what we use.

1. Make about 500ml of celery juice and stir a quarter teaspoon of probiotic powder into it. This is your starter culture.
2. Shred your vegetables finely, by hand or in a food processor. Fine matters, because a fine shred ferments evenly.
3. Set aside one whole cabbage leaf per jar.
4. Pour the starter culture over the shredded vegetables and mix it through thoroughly with clean hands.
5. Start filling a jar.
6. Press the vegetables down firmly as you go, then add more. Pack tight, and stop well before the top of the jar.
7. Lay a whole cabbage leaf on top and press it down, so it holds the shredded vegetables below the liquid line.
8. Close the lid loosely. Not tight. This step is not optional, and the next section explains why.
9. Stand the jars somewhere with a steady temperature for seven days.
10. Move to the fridge, and start feeding.

On temperature: University of Minnesota Extension puts the working range for lacto-fermentation at roughly 68 to 72°F. Above about 78°F you get over-fermentation and spoilage, and Clemson Extension notes that above 75°F the vegetables tend to go soft. Below 60°F it may not get going at all. A kitchen cupboard away from the stove is usually right. A sunny windowsill is not.

Why does this recipe use a culture instead of salt?

This is the question a knowledgeable reader asks, and I want to answer it honestly rather than skip past it.

Every university extension recipe for sauerkraut relies on salt, and those sources are explicit that you do not reduce the salt in a tested fermentation recipe, because the salt is part of what makes the process safe. It gives the lactic acid bacteria the advantage over everything else in the jar.

Our recipe takes a different route to the same place. Instead of using salt to hold back the competition, it adds the bacteria you want directly, in quantity, at the start. There is real research behind why that matters. A 2011 study in Food Chemistry compared sauerkraut inoculated with selected lactic acid bacteria against sauerkraut left to ferment on its own. Every biogenic amine in the inoculated jars stayed below 100 ppm through storage, while the uninoculated control climbed above 200 ppm by day 45. Biogenic amines are the compounds that build up in a ferment left to chance, and a 2025 survey of commercial sauerkraut and fermented cucumbers found several supermarket samples exceeding the estimated upper limit on the amine index.

So: inoculating is not a shortcut around safety, it is a different mechanism, and it is the one I trust in a jar going into my dog's bowl. But the two approaches are not identical, and I am not going to pretend they are. If you want the extension-tested route, use the salt-brine method and check the final pH with test strips. Properly fermented vegetables reach pH 4.6 or below, which is the acidity level extension guidance names as the safety threshold.

What the culture is, matters. A dairy-based human yogurt culture is the wrong tool for a dog. What you want is a multi-strain powder built for dogs, with the strain list on the label.

How do I stop the jar cracking or overflowing?

This is the part nobody warns you about, and it is the reason most first batches end in a mess on the counter.

Fermentation produces carbon dioxide. A lot of it, fast, in the first few days. If the lid is screwed down tight, that gas has nowhere to go, and pressure builds inside a sealed glass jar. University of Wisconsin-Madison Extension is direct about it: the lid goes on only tightly enough to keep air and insects out, never tight enough to trap the gas the fermentation produces.

Four things that keep a batch off your floor:

1. Loose lid, every time. Turn it until it catches, then stop. If you own airlock fermentation lids, use them.
2. Stand every jar on a tray or in a shallow pan. Extension guidance builds this in, because liquid pushing out during active fermentation is normal rather than a failure. Liquid that has escaped does not go back in the jar.
3. Leave headspace. Do not pack to the rim. The contents expand as they bubble, which is what forces the overflow in an overfilled jar.
4. Use several smaller jars rather than one big one. University of Tennessee Extension notes that mason jars are acceptable for fermenting but carry higher spoilage losses than a larger vessel, because keeping everything submerged in a jar is harder. Smaller batches also mean a failed jar costs you one jar.

And keep everything under the liquid. University of Illinois Extension is clear that oxygen exposure at the surface is what permits mold and film yeast to grow, and recommends keeping the contents one to two inches below the brine line. The cabbage leaf in step seven is doing that job. A glass fermentation weight on top of the leaf does it better.

What if there is film, mold, or a strange smell?

The honest answer to are fermented vegetables safe for dogs is yes, with two conditions: the right vegetables go in, and you know when to throw a jar out. You will find plenty of human fermentation forums telling you that a white film on top is harmless wild yeast, and that you can skim it and carry on. That may well be true for a person. I hold a stricter line for a dog, for one reason: your dog cannot tell you the jar tasted wrong.

So the rule in my kitchen follows the extension guidance rather than the forums. University of Kentucky Extension and the National Center for Home Food Preservation both say to check fermenting vegetables several times a week and remove any surface scum as it appears, and to discard the contents if they turn soft or slimy or develop an off odor.

In practice, that means:

• Bubbles, cloudy liquid, a sour smell. That is a working ferment. Carry on.
• A little liquid on the tray. Normal. Wipe it up, do not pour it back.
• Surface scum. Lift it off with a clean spoon, push everything back under the liquid, and use that jar sooner rather than later.
• Anything fuzzy, raised, or coloured. Anything slimy. Any smell that reads as rotten rather than sour. The jar goes in the compost. Sanitise it and start again. A head of cabbage is cheap.
• Any uncertainty at all. Same answer. Compost it.

I have thrown out batches I was not sure about, and I have never once regretted it.

How much fermented vegetables do I feed to my dog, and how do I start?

Let me be real for a second about the numbers you will see quoted online. The figure repeated almost everywhere is half a teaspoon to a teaspoon per twenty pounds of body weight daily, sometimes up to three teaspoons. Every source I could find for that range is a holistic blog or a brand blog, including the write-up of our own recipe. There is no published canine feeding study behind it. I would rather tell you that than pass a number off as research.

What I do: start at a quarter teaspoon a day regardless of your dog's size, for a full week. Then, if stools stay normal, build slowly toward the range above. Fermented food is potent and the bowl is not a race. Mixing it into a meal rather than offering it alone helps with the sour flavour, and a spoonful of the liquid works for a dog who picks the vegetables out.

Two situations where I would go slower still, or wait. A dog with an ongoing digestive condition, where a new fermented food is a variable you do not need in the middle of working something out. And a dog whose symptoms flare on fermented or aged foods, which some dogs do. If either describes your dog, this is a conversation for your vet before it is a project for your kitchen. Our Gut Soothe pre and probiotic blend with soothing herbs is the more measured place to start while a gut settles, and it removes the variability a homemade batch introduces.

How long does a jar keep?

Once the seven days are up, the jar lives in the fridge, where the cold slows the fermentation right down.

Extension sources give fully fermented sauerkraut several months refrigerated, but every one of those numbers assumes the tested salt level, and ours has no added salt. I am not going to borrow a shelf life that was measured on a different recipe. In my kitchen a jar gets used within about a month, and I check it every time I open it. If it has been sitting longer than that, or anything about it has changed, it goes.

Practical version: make a smaller batch more often. Three small jars used inside a month beats one large jar you are still eyeing suspiciously in week six.

Watch me make a batch

If you would rather see the shred, the packing, and how loose that lid actually sits, the whole process is here.

Homemade jar, or a daily powder?

These are not competitors, and in our house they alternate depending on the week. If you are deciding where to put your effort first:

One jar of vegetables is not going to change your dog's life this month. That is not the point. The point is that in five years, the dog whose bowl had live food in it most days is a different dog from the one whose bowl did not, and you will have spent about twenty minutes a fortnight getting there. That is the kind of maths I like.

With gratitude, Charly

Sources

• Sun HY, Kim KP, Bae CH, et al. Evaluation of Weissella cibaria JW15 probiotic derived from fermented Korean vegetable product supplementation in diet on performance characteristics in adult beagle dogs. Animals, 2019;9(8):581. doi.org/10.3390/ani9080581
• Knez E, Kadac-Czapska K, Grembecka M. Effect of fermentation on the nutritional quality of the selected vegetables and legumes and their health effects. Life, 2023;13(3):655. doi.org/10.3390/life13030655
• Subedi U, Raychaudhuri S, Fan S, et al. Fermenting kale enhances its functional food properties by increasing accessibility of key phytochemicals and reducing antinutritional factors. Food Science & Nutrition, 2024. doi.org/10.1002/fsn3.4195
• Scheers N, Rossander-Hulthen L, Torsdottir I, Sandberg AS. Increased iron bioavailability from lactic-fermented vegetables. European Journal of Nutrition, 2015. doi.org/10.1007/s00394-015-0857-6
• Effect of fermentation of chosen vegetables on the nutrient, mineral, and biocomponent profile in human and animal nutrition. Scientific Reports, 2022;12. doi.org/10.1038/s41598-022-17782-z
• Raghavan M, Knapp DW, Bonney PL, Dawson MH, Glickman LT. Evaluation of the effect of dietary vegetable consumption on reducing risk of transitional cell carcinoma of the urinary bladder in Scottish Terriers. JAVMA, 2005;227(1):94-100. doi.org/10.2460/javma.2005.227.94
• Rabie MA, Siliha H, El-Saidy S, et al. Reduced biogenic amine contents in sauerkraut via addition of selected lactic acid bacteria. Food Chemistry, 2011. doi.org/10.1016/j.foodchem.2011.06.062
• Choinska R, Piasecka-Jozwiak K, Swider O, et al. Microbiota and quality indexes of commercial sauerkraut and fermented cucumbers. Environmental Microbiology Reports, 2025. doi.org/10.1111/1758-2229.70250
• Merck Veterinary Manual. Garlic and onion (Allium spp) toxicosis in animals. merckvetmanual.com
• Lee KW, Yamato O, Tajima M, Kuraoka M, Omae S, Maede Y. Hematologic changes associated with the appearance of eccentrocytes after intragastric administration of garlic extract to dogs. American Journal of Veterinary Research, 2000;61(11):1446-1450. avmajournals.avma.org
• Yamato O, Tsuneyoshi T, Ushijima M, Jikihara H, Yabuki A. Safety and efficacy of aged garlic extract in dogs. BMC Veterinary Research, 2018. doi.org/10.1186/s12917-018-1699-2
• Belec K, Barc J, Lasek O. The effect of the type and concentration of garlic on Heinz body concentrations in canine erythrocytes, an in vitro study. Animals, 2025;15(21):3188. doi.org/10.3390/ani15213188
• Guitart R, Mateu C, Lopez i Agullo A, Alberola J. Heinz body anaemia in two dogs after Catalan spring onion ingestion, a case report. Veterinarni Medicina, 2008;53:392-395.
• University of Minnesota Extension. Preserving food at home: Fermentation. extension.umn.edu
• University of Illinois Extension. Fermenting. extension.illinois.edu
• Clemson Cooperative Extension. Making sauerkraut. hgic.clemson.edu
• University of Wisconsin-Madison Extension. Make your own sauerkraut, B2087.
• University of Tennessee Extension. Make your own sauerkraut.
• University of Kentucky Cooperative Extension. Home canning pickles and fermented foods, FCS3-582.
• National Center for Home Food Preservation, University of Georgia. General information on fermenting. nchfp.uga.edu

Please keep in mind that I'm not a veterinarian, and this isn't medical advice. Every pet is unique, so I always recommend working alongside your vet, ideally a holistic or integrative vet, especially for anything ongoing or serious.