Comfrey tea, or comfrey fertiliser, is an all-organic, easy to make plant food that provides excellent nutrition, especially for flowering and fruiting plants. As Alys Fowler explains: “Comfrey is rich in potassium (K), which is required for fruit production, and also contains potash (P) [edit: Potash is actually another term for Potassium, P is actually Phosphorus] and nitrogen (N). A liquid comfrey feed has a higher NPK ratio than farmyard manure.”
Please N.B. comfrey tea is for use on plants only, and is not for drinking. Although comfrey can be used to ease inflammation via topical application in poultices or lotions, the plant is toxic if ingested and could seriously damage your liver.
Comfrey (Symphytum spp.) is a quick-growing deciduous perennial. The recommended variety to grow for tea production is Bocking 14, which is sterile and so not invasively self-seeding (although it will re-grow quite happily from even a tiny bit of root), but if you already have common comfrey on your plot it’ll work just as well and give you a good reason not to weed it out (as if comfrey being an amazingly bee-friendly nectar source wasn’t reason enough).
When I make comfrey tea I use a method that was told to me by no-dig guru Charles Dowding, which is also the method recommended by Garden Organic, and it goes something like this:
1. Harvest Your Comfrey
Comfrey dies back in autumn and begins to re-emerge round about the start of April. By mid-May it’s probably looking like this:
Opinions differ as to whether or not to chop the entire plant off a couple of inches above ground (the fastest method) or to cut individual leaves. I prefer the latter, taking the largest leaves and leaving around a third of the smaller leaves to aid re-growth. I also leave any flowers or flower buds on the plant – bees love ’em – but you can remove the flowers to make more energy available for leaf production if you prefer.
2. Tear, Crush, Pack in a Pot
All good tea needs a good teapot, in this case consisting of an inner and an outer container. For the inner, I use a bog-standard terracotta plant pot with a single hole at the bottom, and for the outer a plastic plant pot without any drainage holes. The terracotta pot should fit inside the plastic pot snugly, ideally with at least a couple of inches of clearance underneath.
Crush, tear or otherwise bruise the comfrey leaves and pack them tight into the pot, filling it right up to the brim if you have enough leaves.
Some comfrey tea recipes will tell you to add water at this stage, but that method will result in an almighty stink as the plethora of bacteria and microorganisms in the water get to work on digesting the comfrey and fart out all sorts of waste gases.
For less stink and a more concentrated end product, do not add water. The leaves will rot down quite happily with the help of the bacteria and microrganisms already living on them, the yeasts in the air etc., (which for some reason are a lot less, er… farty. And yes, that was the science bit…)
3. Put a Lid On It
The lid needs to be big enough to cover the pot and keep out the rain (no water, remember?) and heavy enough that it won’t be blown away in the wind. I use a small concrete paving slab, but a plastic lid weighted down with a brick will do just as well.
4. Leave it Alone
The tea brewing process takes around 8 – 12 weeks, largely depending on the weather (the warmer, the quicker). You’ll know it’s done if you take a sneaky peak under the lid and see that the comfrey leaves have all-but disappeared (any plant matter remaining in the inner pot can be added straight to your compost heap) and the bottom of the outer container will be sloshing with lovely, thick, brown-black, concentrated comfrey tea, which you can drain off and store for when you’re ready to use it on your plants.
The volume of liquid you end up with will obviously depend on the volume of leaves and size of container you brew in. The pot I use makes about a quarter litre, which isn’t a huge amount, but I’m gradually expanding my production capabilities by adding more comfrey plants to a row beside the compost bins, as and when I find the seedlings growing elsewhere on the plot.
5. Slosh it Around
To use your comfrey tea, you’ll need to dilute it to approximately 1-in-20. So for a standard 10-litre watering can, that’s about half a litre of concentrate. You can then use the feed on your fruit bushes, fruit trees, courgettes, squashes, tomatoes, cucumbers etc. to aid with fruit set and development, or on your flowering plants to boost their blooms.
For a more nitrogen-rich feed to use on your leafy veg, you can make nettle tea via the same method. (I confess I’ve had mixed results with nettle tea in the past – I didn’t seem to get anywhere near as much end-product for the same volume of leaves – but I’m trying again this year, so we’ll see what happens.)
How about you? Are you a fan of comfrey tea? Do brew it up by a different method, or can you suggest an improvement or refinement to the above? Let me know, via the comments…
59 replies on “A Simple (and Stink-Free) Recipe for Comfrey Tea”
Make sure you use a food grade bucket, as this is going on your veg!
I made my self a hessian tea bag
I used 5kg of comfrey to 25 litres of water
I’m on week 1 looking ok at the moment
I also have wormeries for extra feed
What about adding EM1 to a comfrey tea? Would that cut down the stink? I’m just kinda curious.
No stink unless you add water.
If it’s so good for so many flowering plants why not use a bigger container?
Use a black plastic dustbin … Drill a few holes at one edge of the base and tilt the bin slightly towards them. Sink a plastic paint kettle or similar in the ground under the bin. In good warm late Spring weather you’ll get a couple of litres of concentrate (if you can fill the bin!) in 2 to 3 weeks!
Hi Roy – Yeah, since I wrote this a few years ago I’ve started using an old catering oil barrel with a screw-on lid and a water butt tap installed on the front. It’s about a 20l barrel, makes up a few litres of concentrate at a time. 🙂
Because she’d rather not use plastic if it’s going to go on her veggies
How long will it last your odour free comfrey liquid last for? can I save it for next year?
Yes, it should be fine for a few months as long as you store it in an air-tight container.
Thanks for all the great input. But I prefer specific answers and as usual with the internet there are as many opinions as people so I don’t know what to believe. Here’s my question- I chopped up the comfrey leaves last September , stuffed a new 5 gallon bucket full, and added water. I then put the lid on this new bucket and left it outside to “steep “. I did another bucket the same way, but stored it in an unused greenhouse which is warmer than our freezing outside CT temperatures . Both are still unopened. Is the tea useable or should I start over? I don’t want to harm my berries and veggies if the 8 month old tea is unsafe!
Hi Gary – I think your comfrey tea should be usable, yes. Based on your description, I wouldn’t have any qualms about using either batch on my allotment. As long as you’re not using it as a foliar spray, and are applying it directly to the soil, then any microorganisms, yeasts etc. that have developed over winter should be incorporated into the soil ecosystem and shouldn’t pose a risk to your plants. If you want to be sure, try applying the tea to a plant that’s potentially expendable, and see if it has any obviously adverse affects over the next couple of weeks. If nothing untoward happens, I reckon you’re good to go.
Hi, I’m curious if your concern was the bucket? I’m about to venture down this path and like you, confused!
I am def into the no stink recipe do let us know! Thank you.
I’ve used comfrey tea I made in the fall the following year with no problems
My concern with this method would be the lack of air, if the lid is tightfitting. The solution would turn anaerobic in just 3-4 days with an airtight lid, and anaerobic decomposition can produce some highly toxic compounds. Like someone else suggested, I’d try it on a single plant first and see what happens. If the future, I’d suggest not completely cutting off oxygen supply. Aerobic decomposition happens faster anyway.
Hi Dan – Good point re: anaerobic issues. Do you think there’s likely to be plenty enough air in the container in between the squashed-up leaves and stems of the plant in the container? Or is it best just to make sure any lid isn’t too tight-fitting? I suspect in the method I’ve described above the would be plenty of air-gaps between the pot and the concrete slab ‘lid’..?
The production of the actual liquid comfrey tea, whether it is the stinking stuff or the concentrated stuff is no problem.My problem is the actual diluting of the tea , I have read so many coflicting bits of advice.
What do you do, include how you apply your diluted mixture.
Hi everyone.
I’ve been growing & making comfrey for a long while, over two decades in Wales, UK. It won’t keep until next year because it is constantly producing gases – if placed inside a sealed container it will probably explode over time!!
However, if left in a loosely covered container, so rainwater can’t enter, it should be fine. It’s so easy to make fresh, there’s no point, imo or simply layer the fresh cut leaves around the base of your plants – they’ll wilt & break down far quicker than other leaves will & the leaves have silica on them, which seems to deter pests aswell. Personally, I prefer to add water to make the nutrient liquid, because the ‘no water’ method takes all summer to produce – just be sure to wear old clothes or overalls, when in use.
As for the dosage – I use a quart liter for every 10 – 12 litres of water..placed into my watering can…you can’t overdose – because it’s organic – we only add it to water to disperse it easily – you could pour it around the roots & let rainwater do the rest.
I’ve experimented over the years & half a litre in the 12L watering can works best on all of my food, flowers & fruit.
I double dose only for my squash and pumpkins, because they double in size..I only use it from the time the flowers show in the vine..hope this information helps.
I also make a comfrey salve for my arthritic hands & feet & we used to feed a few leaves to our chickens, cuz it’s good for their feathers – we also noticed an increase in the amount of eggs laid, while they were receiving the comfrey during summertime & I’ve heard it improves the condition of horse skin (apparently racehorse owners used it a few days before a race to make the fur shine)
Adding twice this amount won’t harm plants, infact it improves the size of your fruits – but you’ll need to make a much bigger batches to last you through the season.
I chop the entire plant down to use. Flowers & all. It grows back in a few weeks – on average I get 5 batches of comfrey tea per summer..I grow the variety known as Bocking 14..because it doesn’t spread about on the wind by seed. But it does spread from the roots. Be careful where you plant it, because its so stubborn & has extremely deep roots, you’ll struggle to get rid of it once rooted. Be warned, an entire plant can grow from a tiny piece of the root – be careful during the harvesting of its roots, that none is dropped accidentally.
Fantastic info, thank you Jason!
Your explanation of N. P.K in the intro is erroneous and requires correction:
N is an abbreviation for nitrogen; P is not Potash ( -potash being wood ash, a natural source of Potassium), but is Phosphate. And it is K which is Potassium. So, Comfrey tea is great stuff; you just need to replace the word potash with Phosphate.
Hi Christopher – Good point (but not my explanation – copied and pasted from the article…) I’ll give that a quick edit.
another post/ u-tube used brown sugar – to ferment. similar to kombucha or wine/ beer making. Also mentioned was a Bamboo “brew” for nitrogen. Always start very diluted & wait . my leaves started actually pointing UP, for calcium – eggshells & vinegar HAPPY GROWING . google KNF https://www.gardenmyths.com/korean-natural-farming-knf/
In Germany they add rock dust (Gesteinsmehl) to neutralize the stinky plant brew used as fertilizer. A handful to 10 litres of water. It also increases the mineral content of the fertilizer. Dolopril also works, as it is lime stone rich in calcium and magnesium carbonate. Don’t use on acidic soil loving plants such as blueberries, azaleas, rhododendrons, heather, camellias, which grow naturally in moorlands and marshes.
Thank you Loretta, good info!
Can the recipe provide positive growth responses if used alone?
Curious if dried and crushed comfrey leaves would feed the plants as well as the tea?
i’ve read you can just add the leaves to the base of plants. Still breaks down. I tried on top but they dried out. Maybe chop up and mix into the soil?
Hi Dassana – Yes, you can use them as a top mulch, but as you say, they’re more likely to dry out. Adding them to a compost heap to help enrich the mix is also a useful way to use them. But the comfrey tea delivers the nutrients right to the plant roots, so probably tends to be more effective.
Put them under mulch & water in if you can..
I have dried and powdered comfrey leaves and used the powder at the bottom of the planting hole for tomatoes. All my plants grew well and produced well. Not necessarily superior to any of the other applications discussed; I dried and powdered the leaves at the end of my growing season in Northern California so I would have some fertilizer to use before the comfrey came back from the winter dieback. It is concentrated so experiment before adding a lot to small seedlings.
Can you use dried comfrey leaves or the powdered form of comfrey that some herbal shops sale to make the comfry tea fertilzer? My students have a project that they will be performing on the benefits of adding comfrey tea fertilizer to plants and we do not have enough time to grow the plant. Due to the short time frame we would have to use either the dried leaves or the powdered form.
Hi Donna – I’ve never tried making comfrey tea from dried leaves myself, and I don’t know enough about the chemistry involved to be able to say whether the macronutrients (N, P, K etc.) would be retained throughout the manufacturer’s drying process though, and if so, in what concentrations. it might be an interesting experiment to try in its own right?
I’ve been making comfrey tea for some time, then one year on Gardeners’ World I watched an older gardener who said he doesn’t bother with all that faff, just chops the leaves and stalks straight onto the plot. I tried that. Bumper crop. Don’t sweat the detail!
Hi Linda – Absolutely, comfrey makes a great chop & drop fertiliser for larger areas. But I’d say a dose of comfrey tea is still useful for containers and greenhouse plants. Plus house plants of course, where a pile of decomposing leaves might not be quite so welcome..?
That’s what I’ve done many times & like yourself, have had great crops from the enrichment of comfrey leaves & their stalks.
Also, when comfrey leaves dry from the sun it’s no different to drying fruits/leaves in your dehydrator, so dry leaves work fine as fertiliser.
I believe comfrey is the quickest & the best fertiliser & soil conditioner.
Great to hear of your success Linda
After I make this,comfrey tea, do I dilute it with water?, how much tea to how much water. Plus how often can I water my house plant’s with this tea?
If you’ve made the no-water version then yes, to use your comfrey tea, you’ll need to dilute it to approximately 1-in-20. So for a standard 10-litre watering can, that’s about half a litre of concentrate.
And it should be fine for houseplants, especially flowering ones.
Ive used Comfrey extensively on my plot for the last 5 years. Once the comfrey plant has grown sufficiently I just rip out the leaves and pack into a large pot with drainage holes topped off with a piece of well fitting wood weighted down with a couple of house bricks. Once the goo starts to flow I keep topping up with new leaves and decant the collection bucket from time to time into fizzy drink bottles – I use the 2.5 litre bottles which I mark at half litre intervals making it easy to measure out the concentrate at 20:1
I have several full bottles at the end of the season which I store in my Allotment shed ready to be used once my crops have been planted out in early May (UK). At this point the comfry plants are not large enough to harvest so this early supply is a big bonus. I have access to lots of Comfrey so any excess gets thrown into a large 240L rain barrel topped up with water (stinky) which I feed at 10:1 – the stems get removed from time to time and thrown onto my compost pile (very stinky process)!
At the end of the season after I have removed the spent crops, I collect as much comfry as possible and trench the leaves at about 1 foot depth topped off with the last of the lawn grass cuttings then cover over and finally a sprinkling of Green Manure. The following spring requires a quick digging over and weeding topped off with compost ready for planting for the new season. This method works great for me.
Hi Bungy – apologies for the late reply, and thank you very much indeed for the detailed methodology. Sounds like you’ve got a comfrey tea production line in full swing there!
Hi Bungy,
That’s a great explanation & the method I’ve used for years myself.
You build a fantastically healthy rich soil into which you plant your crops &/or add to your orchard.
Thankyou for sharing for Newbies & great to have a likeminded gardener to admire results with as well.
Cheers Ria
I use an 80l black bin, mainly comfrey and nettles. Add the water and leave to “stew”, then just top up with weeds and water from time to time. As it’s down the garden away from the house the smell isn’t an issue. We use it mainly for the fruit trees.
Yep, if you’ve got the distance and/or don’t mind the stink then the with-water method is quicker, and the feed comes pre-diluted.
When I lived in Illinois, I had a huge patch of comfrey when I planted my garden I would tear up leaves and mix it in the soil before putting the plant in. I also made a large barrel with the leaves and water and yes it’s stunk, but boy do you get big results I had super huge tomatoes and peppers and everything else I am now in Florida and I found it difficult to grow Comfrey but I finally have two decent plants. This is my first year of planting with it and today I made the fertilizer with water. We’ll see how it goes.
Fingers crossed your Florida comfrey continues to do well!
Darrel , What size did. you use in this article.. Just trying to gauge the ratio of pot size to yield size
It was a plastic plant pot, about 5 litres, maybe 6?
Thanks – all the info I was looking for! Garden in Kansas, USA and soil test shows 0% potassium and I’m not interested in So-Po-Mag. Thought I’d planted the comfrey 2 years ago for the bees and now it’s the answer to the soil’s deficiency. Excellent!
Hi Mona – You’re welcome! I’m glad it was helpful.
Thanks Darren
Good clear information that is very useful and also the good grace to accept other opinions and ideas.
Just planted my comfrey in the subtropics and looking forward to brewing up a non stinky batch come summer… Vege garden is in full swing now as we are winter vegetable gardeners in the main.
Happy days
Thank you Delwyn. I’m always keen to hear other opinions when they have something useful to add to the discussion and especially if I learn something in the process – every day’s a school day.
Best of luck with your subtropical vege garden!
I regularly use comfrey tea, but when I have an abundance, love to chop it up and use it as mulch. Best pepper crop ever, and it leaves the soil rich and perfect for next year.
I’ve made two batches of comfrey tea in a couple of plastic dustbins with lids that I bought for the job. I added water (sorry) but have no idea now what dilution would be needed or what I should really be doing with it. I’m in the UK so maybe I’ve missed the time to be using it anyway – if so is it worth me just pouring it onto my compost heap? I can start making some again next year. I do have a lot of fruit in my garden (gooseberries, blackcurrants, strawberries, raspberries, so should I be pouring it on them now or would you do it at the start of the growing season? Sorry for my ignorant questions – I’m new to gardening!
Hi Jo – You’re right that it’s probably too late for using up your comfrey tea this year, unless you have any late-flowering plants that could do with a boost. You could also try bottling it and keeping it until Spring, (although there’s always a slim chance of an explosion if the liquid continues to ferment and the pressure builds up) or just keep the lids on those dustbins until you’re ready to use it next year, then start over again with a fresh batch. Dilution-wise, if it’s already quite dilute from being made with water, I’d say use it as it is, or if you’d rather weaken it a bit then maybe 1 part comfrey tea in 3 or 4 parts water, something like that.
Darren, thank you for the excellent review of comfrey tea.
I’m just starting to experiment with year-round gardening with a focus on hydroponics, possibly starting with the Kratky method. Have you experimented with hydroponics or can you point me toward any fellow growers using comfrey teas in hydroponics?
Hi Chuck, sorry, no, I’ve not experimented with hydroponics at all. Best suggestion I’ve got would be to see if there’s a local hydroponics supplier or growing club who might be able to advise.
I would think it would be a great liquid fertilizer added into the hydroponics water!
I love Comfrey! Ive planted a few through the years and they have spread and now have many! I recently transplanted 6 in my one 4×4 raised bed so I will have a patch for my use and the Bees too! Teaching my daughter and grandson who are starting out gardening on the awesome uses of comfrey. Ive made comfrey salve for many years.. my teenage daughter used it for yeast under her arms.. lol she didnt mind being stinky cause it was the only relief she could find. When I was a kid my dad used the same method of making tea with chicken poop… grew a fantastic garden. I still have his pot with a long handle he rigged up 60 years later.
Every time I read about comfrey tea, it only mentions the leaves? Are the stems/flowers/roots a problem? Does it make the fertiliser toxic?
What about just brewing a pot of tea from the leaves (boiling water over leaves, steep) then (cool, of course) dilute and go?
I saw this on a show once somewhere–
Thanks very much for this tip! It worked wonderfully, especially during this (2026) hot summer.