Discussion forum for environmentally-friendly alternatives to replace synthetic chemicals and fertilizers.
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July 2, 2015 | #1 |
Tomatovillian™
Join Date: Jun 2015
Location: UK
Posts: 45
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Comfrey tea in UK greenhouse
I was wondering if anyone has tried just using comfrey tea as fertiliser and what sort of results they got.
It's my first season growing anything and decided to try just using comfrey tea after seeing it on BBC's Beechgrove Garden programme - it also helps that there's a few good patches of it nearby The only thing I've learned so far is that it stinks and I need to wear gloves whilst making/using it because the smell doesn't leave my skin no matter how many times I wash up |
September 9, 2015 | #2 |
Tomatovillian™
Join Date: Jul 2015
Location: Yarmouth,NS Canada
Posts: 296
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Hi Darren,
Sadly there is no greater benefit to using comfrey in any form then any other plant. It is not superior in NPK, trace elements or anything else we seek. I grew and still have 3 comfrey plants that i planned on using as a fertilizer. I even made 2 batches of stinky tea. I did use the tea and anecdotally, didn't see any difference. Just recently, I put the question of comfrey use to the Garden Professors, a highly qualified authority in the world of Horticulture. They said i was wasting my time basically. Here is a link to the discussion on facebook. https://www.facebook.com/groups/Gard...4113272051490/ Cheers Mark |
September 10, 2015 | #3 |
Tomatovillian™
Join Date: Jun 2010
Location: Romania/Germany , z 4-6
Posts: 1,582
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UK sure loves comfrey tea. I see it on uk forums all the time. I've wondered where they get it from, over here it's a pretty rare plant.
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September 10, 2015 | #4 |
Tomatovillian™
Join Date: Jun 2015
Location: UK
Posts: 45
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Thanks for the replies.... I will have to do more reading, obviously
It's quite a common plant near my home, I have 4 plants in my garden as well and most allotments have a patch of it... We seem to be coming to the end of our summer here, the night time temps are getting dangerously low (4*C last night) I've been using comfrey tea all year, with no other fertiliser - I have nothing to compare it to but my plants seemed to have done ok. Next year I will try a comparison and grow 3 plants, unfertilised, comfrey and a normal chemical fertiliser (if I can find the space in my greenhouse) I would say that I'm not dismissing the advice but there's a gardening programme on TV here called Beechgrove Garden and they did exactly that comparison last year and the comfrey plant was the most productive. This also might explain why it's all over UK gardening forums Last edited by DarrenC; September 10, 2015 at 03:38 AM. |
September 10, 2015 | #5 | |
Tomatovillian™
Join Date: Jul 2015
Location: Yarmouth,NS Canada
Posts: 296
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Quote:
I got inspired from reading about a master hot pepper grower in the UK using it. So I will blame you Uk'ers if it doesn't work ! Cheers, Mark |
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September 10, 2015 | #6 |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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Sometimes I forget that gardening is a bit of a competitive sport. Especially when it comes to the best fertilizer, or 'organic' vs 'conventional/chemical' methods... the more competitive sorts do love to trash what others do, whether they have evidence or not.
I remember reading that comfrey was high in potassium in my (very old) copy of the Encyclopedia of Organic Gardening. Just googled and, at the least, this article by Rodale cites some actual analytic test results of what actually is in comfrey. http://www.rodalesorganiclife.com/garden/comfrey-power "Researchers in British Columbia analyzed the NPK (nitrogen, phosphorus, and potassium) ratio of comfrey leaves by air-drying them and analyzing the powdered leaf tissues. They found that the leaves have an impressive proportion of 1.8-0.5-5.3. To compare, kelp meal has an NPK ratio of 1.0-0.5-2.5, and homemade compost ranges from 0.5-0.5-0.5 to 4-4-4 (depending on what ingredients you use). Comfrey is also rich in calcium and many other valuable plant nutrients it mines from deep in the subsoil." I've been using crushed kelp as a source of potassium, but I got a reminder this year, that kelp won't break down quickly at all in cold soil, and left the plants deficient in the bad weather. I'd be better off using comfrey, since it should break down much more easily. I still have some comfrey in the garden in spite of my efforts to remove it a few years ago. Guess I should take care of it and make a thriving patch... I guess you'd need quite a lot to make up by weight the amount of kelp I drag home from the beach every year. Why do I never find the usefulness of something unless I threw it away. |
September 10, 2015 | #7 | |
Tomatovillian™
Join Date: Jul 2015
Location: Yarmouth,NS Canada
Posts: 296
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Quote:
I read that info before and that is why i started the comfrey after i was inspired by the UK pepper grower. Unfortunately, the data/research isn't supported by the scientific community. When i have more time I will try to go through the garden Professors threads to see exactly why. I would love to see comfrey prove its worth in the garden as I put a lot of effort into getting the seed here. Like I said earlier, i will trial it out better this year. I have only used Kelp meal once , threw a few cheap bags on my neglected lawn back in Moncton, NB. You could see where i ran out in terms of lushness and health. I also really liked marine compost, except if the shells were not composted enough. Cut my hand a few times with one batch. No kelp meal or marine compost here in Mendoza . Could you use the kelp as a top dressing instead ? Maybe it would benefit you in the long run but not cause any deficiencies in the short run. Or just compost the heck of it for a few years before you use it. Free kelp would be hard to turn down. Cheers, Mark |
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September 10, 2015 | #8 | |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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About the 'professors', are you sure they're not turning up their noses on principle and without good reasons? It wouldn't be the first time that I heard scientists scoff just because they heard some other authority say so, and took it on 'authority' alone and/or out of context, without basing their claim on any actual data. My best guess is that 'comfrey tea' in the recommended dilution etc was not found to have an amount of nutrients equivalent to some other liquid fertilizer ie strong enough to have effects. Just as the 'kelp extracts' which are sold for mucho dinero are used so dilute that they have only a hormonal effect but no significant or measurable nutrient contribution. That doesn't mean there's no potassium value in bulk raw kelp, obviously. I think a dry comfrey leaf probably doesn't weigh much and it would take a lot of em to make a pound of 'comfrey ferts', with the label value of NPK that was found in that legitimate study, quoted by Rodale. Weak tea is a whole other matter, of course it won't have the same value if it's mostly water. I think I'd be tempted to try the other method described in the Rodale article, just weighting down the raw leaves and letting the rotted liquid drain into a bucket below, then bottle and dilute for use as we do with eg fish emulsion to keep from burning the plants. The liquid product before dilution should have a nutrient value close to or equal the measured value for dried leaves in the study.... and it's not bad, it's certainly comparable to the values listed on my fish e bottle or my dry chicken manure stuff. Which are not free, like a heap of otherwise useless comfrey would be free. For the labour of making it. If the actually measured NPK value of raw comfrey material is disputed by the 'professors' on scientific grounds, I'd be interested to hear about that. I haven't seen or reviewed the methods used in the cited study, I'm taking on faith that the science was properly done. |
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September 10, 2015 | #9 | |
Tomatovillian™
Join Date: Jul 2015
Location: Yarmouth,NS Canada
Posts: 296
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Quote:
Just to clarify about their answer to comfrey, it isn't useless. It just is not any better then any other plant. If you have ever made the tea, you know there is some personal benefit to not having to ever make it again. I call it liquid bum. Last edited by MendozaMark; September 10, 2015 at 03:11 PM. |
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September 10, 2015 | #10 | |
Tomatovillian™
Join Date: Jun 2015
Location: UK
Posts: 45
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Quote:
I got a 20l bucket with lid, cut the comfrey and left it for a day to wilt then squeezed as much as possible into the bucket, topped with water and then sealed it up in my greenhouse for 4 weeks. From that point on I wear rubber gloves and old clothes whenever I used it. It gave me a dirty water look stuff that I diluted 1:10 or thereabouts with water I used this once a week I've grown all my plants in 13l (about 4 gallon US) containers - because thats what I had... I started feeding them 6 weeks after their final potting on The only problems I've had are the weather has been terrible and all my San Marzano's got BER - apart from that I think it's worked for me, just don't know if it'd be better or worse without it - but I have a real phobia of eating stuff chemically treated/fed which is one of the main reasons I started growing anything I've had quite a lot of cherry toms and a fair few big toms, the biggest a beefmaster at 850g or 1lb 13oz.... Tasty 😁 |
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September 10, 2015 | #11 | |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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Quote:
I'm sorry though, I have to take issue with the evaluation that comfrey "is not any better than any other plant". That would lead a person to believe that all plants have the same NPK values and therefore have identical fertilizer value... and this isn't true. Take a look at this database, the NPK of everything (well... not by a long shot, but a start ) https://www.thenutrientcompany.com/n...able-database/ For example of ordinary leafy plant material, nettles and comfrey are listed next to each other (in the 100 items list) and have unique values for NPK. There's more N in nettles and more K in comfrey. I know my friends used to fill a barrel with water in the spring and toss nettles in there, which they used to water the crops. Maybe nettles were better than comfrey for that application because of the higher N. Maybe comfrey is touted for tomatoes because K is important for fruit quality. Maybe comfrey tea is better in the UK because the soil leans toward K deficiency. Maybe some other plant entirely would serve you better in the Argentina pampas. What I'm getting at, is that saying that comfrey is no better than any other, is like saying that all fertilizers regardless of their NPK are no better than others. That doesn't sound like science to me. Doesn't even sound like gardeners, who do argue mightily about which fertilizer formula is the best!! Is it conceivably possible that the rotting process in 'tea' making could reduce every plant material to the ho-hum balanced 4-4-4 or similar value usually given for "garden compost" ? I'm not sure why or how that could be, if a single plant material with specific NPK ratio is exclusively used. Losses due to aromatic volatiles? You'd expect different 'teas' to smell different, in that case. Incidentally, blackstrap molasses has been recommended as another source of K and trace minerals for liquid ferts. I use it to balance the N-heavy fish emulsion. And guess what... it smells pretty good, compared to plain fish. |
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September 10, 2015 | #12 | |
Tomatovillian™
Join Date: Jul 2015
Location: Yarmouth,NS Canada
Posts: 296
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Quote:
First off , don't shoot the messenger on this one...lol. I am no scientist, don't have a science degree just a gardener who wants to learn. The big issue with the report/research on the NPK analysis of comfrey was there were no controls used. He did not grow anything else but comfrey so no comparison could be done to any other plant in that exact soil with exact same inputs. Also if I grew comfrey and you grew comfrey and we had it tested, would it be exactly the same NPK value? No, it would be dependent on the soil and inputs and other variables. Our results would most likely be different then those of the research paper too . So to say any plant has this NPK value really isn't accurate. If you did not use controls by growing different plants in exact same condition then you can't compare the plants in terms of NPK. That being said, I couldn't find out if proper research was done on comfrey with proper controls. I assumed that research had been done or i would have been told that it was inconclusive due to lack of research, like the mustard question. If I do find something I will post whatever results i find. Lastly, i have 40 liters of comfrey tea brewed and I will use it regardless. Will I make more, not sure. Cheers Mark |
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September 10, 2015 | #13 | |
Tomatovillian™
Join Date: Jul 2015
Location: Yarmouth,NS Canada
Posts: 296
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Quote:
Cheers Mark |
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September 10, 2015 | #14 | |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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Quote:
I couldn't see the picture. 1 lb 13 oz is huge! |
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September 10, 2015 | #15 | |
Tomatovillian™
Join Date: Feb 2012
Location: Newfoundland, Canada
Posts: 6,794
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Quote:
I do have a science degree, which is why I'm critical... not of you, of 'debunkers' who don't actually pony up any data to support their claims, or misapply scientific concepts/methods to confuse less educated folks. To be fair, I couldn't access the blog because I'm not on facebook and I couldn't find the discussion of comfrey by google. And since Rodale didn't name the researcher I couldn't find the research either. I remain in the dark. As regards the NPK figures, this type of data on natural materials is never taken as an absolute - they are ballpark figures based upon the available data. This is what we need to estimate how much cottonseed meal or kelp or comfrey to apply as a fert. From a scientific standpoint "controls" of different plants aren't relevant to this type of data, but the number of data points is important, the more points the better. That means many samples should be tested that grew in different environments, from which an average is taken. It is okay to gripe about someone having only one data point, if that's the case. It isn't sufficient though, to support the claim that comfrey has the same NPK as nettles or hay or some other plant, which according to the available data, are all different. |
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