I have been offered a half size allotment nearer to my home than the one I am currently sharing with a friend  I don't anticipate having much of a harvest there next year as it is going to be a case of clearing and conditioning the soil - it has been neglected for several years.   Whilst I was surveying the site yesterday I noticed the previous holder had a row of comfrey growing at the back.  I think I read somewhere that it is supposed to be good for soil conditioning.  Can anyone please tell me how and when it is used. Does it need to be left and allowed to rejuvenate year after year or is it to be re-sown or something.

Thanks everyone!


  • Gary HobsonGary Hobson Posts: 1,892

    Comfrey is a perennial flower. I grow it in my garden as a flower. It grows vigourously and comes up year after year.

    The main value of comfrey as a fertiliser is that the leaves are high in nitrogen.

    You can dig the plant directly into the soil if you want to. Or you could keep some a a living plant, to allow you to harvest the leaves. These can be left to decompose in water which will make an excellent liquid plant feed.

  • Busy-LizzieBusy-Lizzie Posts: 11,918

    You need a bucket with a lid. Fill it with comfrey leaves and put a brick on them to stop them floating. Fill with water. Leave it for about a month. It will stink! (Hence the lid!) Remove the rotted leaves to the compost heap and you have a liquid feed in the bucket which you will need to add 10 parts of water to 1 part comfrey liquid. It makes a fertiliser high in potassium. Comfrey has deep roots and can spread. When you have cut off all the leaves it will grow more. It was called "knitbone" and has herbal healing properties.

  • Gary HobsonGary Hobson Posts: 1,892

    Sorry, as Busy-Lizzie correctly says, the biggest nutrient in comfrey is potassium. Comfrey is rich in nitrogen, but contains twice as much potassium. Both very useful.

  • jo4eyesjo4eyes Posts: 2,032

    I've never actually made the liquid from my plants leaves, but I do cut them back 2 or 3 times in a season & add the leaves to various compost bins. They act as an accelerator. I also put the leaves beneath my fruit bushes in the spring- nutients then go where I want. J.

  • Wow. Thank yous All!  It has lots of uses then.  I like the idea of an accelerator for compost heaps and liquid fertiliser.  Does it grow out of control do you know?  From what I could see at the allotment, it was just a small row with leaves growing to about 30 - 40cms.  The plot appears to not have been worked for quite atime so I imagine that unless someone has been helping themselves in the meantime, that would be the maximum height.

  • tom9760tom9760 Posts: 44

    as some of the others have said it's best to make liquid fertiliser from the leaves try not to put the leaves directly into the soil as they tend to regrow from every axle on the leaf.i use it all the time and water it down to 1 in 16,half a pint of liquid to 7 1/2 pints of water.

  • Gary HobsonGary Hobson Posts: 1,892

    40cm is as big as it gets. Another very useful aspect of the plant is that it flowers over quite a long period, and is very attractive to bees. I grow it simply as a flower.

  • Thanks Tom and Gary. Something new to try!

  • Found this old thread while doing a search for comfrey as we are overrun by it and I'd like to kill most of it if possible, particularly the stuff that's growing in the lawn, the borders and up a grassy slope that I'd like to sow with meadow flowers.  We have 3/4 of an acre garden and there's hardly a bit the comfrey hasn't reached.

    Having read a number of threads that talk about making comfrey tea as a feed I think that would be a good use for some of it, and possibly using it to accelerate the compost. I'm a bit concerned about putting it on the compost heap as cuttings though as Tom9760 says every bit of leaf might grow a new plant.  Does that make  it a bit of a risk to put on the compost heap then?

    I sprayed some of the comfrey with Resolva a week ago but it doesn't look like it's the slightest bit bothered by it, I do dig some of it out where I can, being careful to get the huge nobbly root out, but I can't do that in the lawn without it looking like a battlefield.  Any tips on getting rid of it in that sort of situation please?


  • Steve 309Steve 309 Posts: 2,754

    I'd have thought that mowing the lawn regularly would sort it out.  Eventually.

    Resolva looks like dodgy stuff:

    If your compost heap gets hot, it should kill the axillary buds.


  • Busy-LizzieBusy-Lizzie Posts: 11,918

    I've put it in the compost and it hasn't spread, it just rotted down. My comfrey bed is next to a lawn and mowing controls it.

  • I wish we just had a bed of it, but it is creeping everywhere, this year appearing in new parts of the lawn where it hadn't previously been.  I don't know if it seeds like mad or spreads underground.  I know it has a chunky root system but we now have new shoots coming up in the grass at least 10 feet from the next nearest clump, which suggests seeds or a motorway under the grass!

    The lawn gets mown regularly, including the rough bit where the comfrey is most virulent but it doesn't seem to put it off, hence assuming some sort of glyphosate would be needed, and on this one I'm happy to use something stronger to control it as at the moment it's more of a nuisance than an asset.

  • Bushman2Bushman2 Posts: 544

    Comfrey is very high in vitamin B12. The leaves were used to make poultices for various ailments. if you don't have any it is often found on riverbanks. one of the good guys but can be a real royal pain in the wrong place. 

  • Busy-LizzieBusy-Lizzie Posts: 11,918

    If you use glyphosate that will kill the grass too. You need a lawn weedkiller.

  • Bushman2 says:

    Comfrey is very high in vitamin B12. The leaves were used to make poultices for various ailments. if you don't have any it is often found on riverbanks. one of the good guys but can be a real royal pain in the wrong place. 

    See original post

     That might explain why we have so much of it in the garden - the house used to be a watermill and we have a burn running around three sides of the garden, albeit the other side of a wall, which is clearly not high enough to stop the natural spread of seeds...

    I'd be happy with a small patch for things medicinal, but I could set up a fracture clinic with the amount we've got!

  • Busy-LizzieBusy-Lizzie Posts: 11,918

    Are you sure it's comfrey? Mine doesn't behave in the way yours does. I've just had a tiny patch in the lawn next to the bed. It did fill the bed, which isn't that big about 1m x 2m, but hasn't gone any further.

  • Bushman2Bushman2 Posts: 544

    Busy some types of Comfrey have different habits or perhaps it doesn't like where it is perhaps to dry for it? image

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