Liquid seaweed - regular use

Discussion in 'Compost, Fertilisers & Recycling' started by ClematisDbee, Apr 15, 2025.

  1. ClematisDbee

    ClematisDbee Gardener

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    Is liquid seaweed a fairly safe tonic to add to the garden? I am thinking of applying it all over the garden, regularly (once or twice a week) maybe in more dilute quantities than generally recommended. Would this help improve poor sandy free draining soil ( without burning roots, worms etc).

    I am a bit wary of using too much liquid feed because I am fairly sure I killed a bush with an application of liquid fertiliser (Tomorite or similar).

    Is liquid seaweed safer than most other types of liquid fertilises, in terms of burns and other problems?
     
  2. pete

    pete Growing a bit of this and a bit of that....

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    I find the seaweed stuff downright expensive for what it is.

    You shouldn't be killing plants with liquid fertiliser if you apply it as directions.

    Twice a week all summer seems bit excessive to me i dont have sandy soil so its different for me but just a couple of applications of something like chicken pellets, during the summer, is about all I would do.
    Probably soil improvement would be a better approach.
     
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    • Plantminded

      Plantminded Total Gardener

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      The best way to improve sandy soil @ClematisDbee is to add organic matter. Over the last couple of years I have incorporated farmyard manure and two different seasonal compost mixes from a local supplier to improve my sandy soil. It has improved water retention, growth and flowering. I didn’t add any this year as I don’t want to overdo it - I grow a lot of grasses and perennials, many of which fare better with lower nutrient levels. I use seaweed extract once a week on the crown and trunk of my tree fern. It is more of a tonic than a feed as the N:P:K ratios are low (and not mentioned on the label).
       
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      • Spruce

        Spruce Glad to be back .....

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        Hi

        it’s a tonic for plants, plus I have done a experiment with my daylilys , fed half with liquid seaweed and they green up in days compared to the ones that never had it.

        I tend to only use in the spring April or if a plant lacks lustre it’s given then.

        Spruce
         
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        • infradig

          infradig Total Gardener

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          Have a look at this to give you a deeper understanding of the potential advantages of its use.
          https://pmc.ncbi.nlm.nih.gov/articles/PMC8000310/e

          I use the Doff brand on all watering of new plants and seedlings at a rate of 15ml/5litre of rain water, increasing to 20ml/5litre immediately prior to planting out, and produce healthy plants.
          As @Plantminded states above, build up the soil organisms by mulching with organic material at least annually; this will achieve the aim of feeding the soil thereby avoiding additional 'supplimentary' feeds.Nature does not need a box or bottle !

          Edit to clarify dilution rate
           
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            Last edited: Apr 15, 2025
          • Baalmaiden

            Baalmaiden Gardener

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            I notice you live on the coast. If you can collect some seaweed (preferably after rain) and put it around your plants it will provide nutrients and help build up humous in the soil. I put loads around my brassicas the winter before last and they loved it. I was going to do the same this year but a trapped nerve means I couldn't carry the buckets this winter. You can also steep some in a bucket and make your own liquid feed but beware - it stinks! I shan't be repeating that as I have to think of the neighbours.
             
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            • Michael Hewett

              Michael Hewett Total Gardener

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              I had an uncle who lived on the coast and he used to collect seaweed along the strand line after a high tide, and put it in the bottom of trenches where he planted potatoes. He used to say it prevented blight as well as feed the potato plants.
               
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              • NigelJ

                NigelJ Total Gardener

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                If I remember rightly some islands (TheAran Isles spring to mind) used and may still collect seaweed and use it as a mulch over winter.
                 
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                • waterbut

                  waterbut Gardener

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                  Ayrshire potatoes were, or maybe still are grown in seaweed.
                   
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                  • Allotment Boy

                    Allotment Boy Lifelong Allotmenteer

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                    I agree the best way to improve sandy soil is to mulch heavily with organic matter. That said I use seaweed TONIC regularly, but no more than once every other week. You could use it at half strength more often. Some seaweed brands are made by chemical extraction, the better (more expensive) ones use steam and water extraction.
                    Tomorite is based on seaweed but also has other added nutrients, but unless you used it very concentrated I'd be surprised that it would "burn" a plant. It's been said previously on this site you shouldn't feed a struggling plant as it just puts extra pressure on it. That said I have "rescued " poorly plants with very dilute seaweed tonic 1/10 sprayed all over with a low pressure fine spray.
                     
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                    • ClematisDbee

                      ClematisDbee Gardener

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                      Thankyou very much, @pete, @Plantminded, @Spruce, @infradig, @Baalmaiden, @Michael Hewett, @NigelJ, @waterbut, @Allotment Boy. Fantastic range of helpful responses.
                      I need to get into a bit of a routine, so I thought if I applied it once or twice a week, it would be something I wouldn't forget about. Memory is getting worse, so I am going to draw up a list of possible jobs to do each day/week, but not set it in stone.

                      Reading your replies, I am thinking I will use it less frequently than planned and very diluted. I am also inspired to do some experiments on areas where it will not matter.
                      I feel I am mulching much of the time, but it is true, my garden soil disappears so fast, maybe I am not keeping up.

                      Thanks too for the link, @infradig and your info. I could not open the link - is it a USA governmental one?
                       
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                      • Plantminded

                        Plantminded Total Gardener

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                        It would help to know which of your plants don't seem to be faring well @ClematisDbee. I would only use fertiliser/seaweed extract for specific plants and reasons and not as a general regular practice. Feeding your soil to improve the microbiome is far more beneficial. Plants in containers will need additional feeding though.
                         
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                        • infradig

                          infradig Total Gardener

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                          Yes it is; but it wont work for me today either!
                          Try this instead- its UK
                           
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                          • Allotment Boy

                            Allotment Boy Lifelong Allotmenteer

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                            @infradig Thanks for posting this. I finally got round to watching it on my laptop as the phone screen is too small. Interesting but as with many of these studies, in order not to show bias they do not recommend specific products, so it's still a bit of a gamble as to which one to buy. There was a product from the Chase organic Called SM 3 (through the organic catalogue) that I used to use but it doesn't seem to be available anymore. I suspect a lot of the products tested in this presentation are only available to the trade. I am currently trying Envii, but in a recent Garden Which trial on tomato feed it didn't come out that well, mind you the market brand leader Tomorite came out even lower!
                             
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                            • ClematisDbee

                              ClematisDbee Gardener

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                              Thank you @infradig and @Allotment Boy.

                              Interesting about Tomorite tomato feed in the trial. I wish I could recall which tomato feed I used that killed a shrub rose. I remember not having time or patience to measure the dosage properly and by the next day it was curtains. Before then it was my healthiest rose. (Versicolour/Mundi).
                               
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