How To: Make your own organic liquid plant food – Fermented Plant Juice (FPJ)
Fermented Plant Juice (FPJ)

How To: Make your own organic liquid plant food – Fermented Plant Juice (FPJ)

Gardeners have been making their own organic liquid plant food for years. Pretty much everybody knows that if you put Comfrey or Nettles in to a bucket with some water and seal the lid you’ll get an apocalyptic, plot wars inducing, foul smelling liquid that’s more nutritious than farmyard manure (FYM) and comes in an organic liquid form to-boot. Excellent!
Well, it is excellent except for the stench, time involved and the fact we’re rather limited with our traditional ingredients!!

If only there was a better way to make an organic liquid plant food?!

Well now there is!* If you ferment your ingredients with a little Lactobacillus (LAB) and sugar you can break down the plant material in to a biologically active, nutritious liquid plant food and the best thing is we’re no longer tied to just Comfrey and Nettles! Carrots? Seaweed? Cucumber? Cabbage? Whatever scraps or left overs you have can be fermented down and turned in to a natural ‘organic’ liquid plant food.

What you’ll need:-
Fruit/Veg/Plant material etc
Lactobacillus (LAB)
Container with good lid
Water (if needed)
Scales (Optional)
Blender (Optional)

Method :-
Weigh or guess the amount of plant material you have, if you have access to a blender blitz this up, otherwise just chop and mash up your plant material as best you can.
Mix your mash with the same weight of Sugar or Molasses – (Unrefined sugar is best – it has less of the good stuff taken out!), if your material is a little dry (like dry seaweed for example) you can add some water to re-hydrate it. Here I add the Lactobacillus using about 30ml for each kilo of mixture (some don’t bother with the LAB here, but I do as it keeps the smell down in my opinion)
You’re pretty much done now, cap your container loosely. You don’t want air getting in, but you don’t want it exploding either!
After 7-14 days your Fermented Plant Juice will be ready, you may see mold/fungus on the top, so long as it’s white and healthy looking that’s fine – Discard if Black or angry looking. It should have some odour, but not unpleasant – Sweet/vinegary/slightly alcoholic is fine, if it smells bad, again, discard it.
Strain your FPJ and extract as much liquid as possible, you can compost the solids or feed to your worms etc.
Bottle up your FPJ and label it properly it should keep for 6-12 months.

Make up an RTU spray by mixing 15-30ml with 1 litre of water and apply as a foliar feed.
If feeding the soil you can make it stronger.

If you’re curious as to the NPK value of your concoction you can use the Fermented Plat Juice calculator to work out a rough estimate!

Other input ideas – Banana, Beetroot, cabbage, carrot, lettuce……….

*if you’re new to this – If you follow the Korean Natural Farming method you’ve been doing it for centuries ;o)

This Post Has 31 Comments

  1. Hi
    Great advice, thanks. Will hope to blog about compost tea, foliage feed, comfrey liquid. But I am a novice at this muck & magic, good to read the science behind the magic.

  2. where do u gget lactabolis

      1. Ok why rice?

        1. It’s an easy carbohydrate source…and you get to eat the rice first, so no waste 🙂

          1. FREDDO

            Hi Nigel. Would boiled potatoe liquid work as a base as they are also high in carbs/starch?

          2. I can’t see a reason why it wouldn’t?!
            Let me know how you get on!!! 😀

  3. if its okay if i will used fermented plant as drink additives on broiler, because the kangkong that i ferment was contain contain a molds after i ferment in just 4 to 7 days, if its dangerous to the animals? but the smell doesnt smell bad and its okay for me to smell the smell is alcoholic, just like that and a little bit vinegar smell. sorry for the grammar im a filipino. thank you very much< hoping you will help me with this matter. 🙂

    1. Hi Niño, many people do use the ferments for animals – Generally if the smell is not foul/rancid and the molds are lighter colours these are allowed.
      But obviously this would be at your own risk – I would do some research in the same methods and maybe try to identify the molds from experienced farmers first.
      Search – “Korean Natural Farming” for more info!!

  4. i’m confused why you would intentionally feed anaerobic bacteria to your plants. Wouldn’t it be best to bubble this for 48 hours?

    1. Hi there, It’s the plant food you’re feeding to the plants, we’re not that interested in the bacteria once they’ve done their job.

    2. The biology that lives on the leaf surface and stem is generally aerobic….The biology that lives in the rhizosphere tends to be anaerobic or a combination of the 2. This is why we use both aerobes and anaerobes. How that anssered ypur question.

  5. Do you not run the risk of feeding the plants too much alcohol? I’d wonder what percentage of alcohol you’d end up with and if it might ferment a whole lot more once bottled causing popped bottles or a fizzy mess on the floor if you try to remove the lid.

    1. There isn’t a great deal of alcohol produced.

  6. Does the fermentation process remove the toxins. Can I use house plant material like a Pothos Ivy?

    1. Honestly you would have to try. There’s no reason to say it defiantly would unfortunately. But I wouldn’t let that put you off doing a small test!!
      I was asked the same about Eucalyptus recently too….

  7. Hello Nigel, on making the lactbacillis culture I did not put it outside and I also put a ballon over the neck of the bottle. So no fresh air you think it cultured properly or should I start over. Thanks for all the great information and directions.

    1. That’s a great question. I guess you will have trapped the gas…. Did the balloon inflate? I would expect it to.
      Did you get the distinct layers of curds and whey? If you did I’d say it probably worked…..

  8. What is the best temperature to store while its fermenting? thanks

    1. I couldn’t tell you the ‘best’ but room temperature will work fine 🙂

  9. Hi,
    Can I use tap water to mix with lactobacillus to spray my Plants? I read it somewhere on internet that the water cannot contain chlorine because it will kill the bacteria. It is very difficult to collect rain water as it seldom rain in Summer in Vancouver.

    1. If it’s just Chlorine you can let the water stand a day or two, or boil it. If you have Chloramine that won’t work, but you could add some organic matter in it first like some soil for the chloramine to bind to.
      Beyond that, just use tap water. It’s not that effective at killing bacteria or we’d wash our hands and surfaces with it….

  10. Raw onions are amazing at removing chlorine very quickly

  11. Hello, I make water kefir every two days, there’s a big variety of LAB bacteria in there, can I use that as a starter for my left over veggies? I just don’t know proportions ? Thanks for helping out this site is very interesting !

    1. You’ll be able to use this…I don’t know the proportions either, but they’ll find their own balance. Experiment!!

  12. Hello, I’m interested in storage information. If I want to make and store some FPJ concentrate, what is the best way to preserve it and keep it “fresh”? I have seen people add more sugar(after the initial fermentation) and then lid it with a paper towel to store it longer. I don’t understand why adding more sugar helps to preserve it. What do you think about this? Also, I assume refrigeration/freezing couldn’t hurt. Any other information on how to best store FPJ would be appreciated. And how long you think it will keep “fresh” with the methods.

    Thank you

    1. 50/50 sugar by weight is a standard storing method. The paper towel – or better an airlock – will let the gasses escape without rupturing the container….
      In terms of NPK I guess you could freeze it, but you’re going to lose the beneficial bacteria.
      …and at this point I’ll give my standard answer – test both and do a side by side next year – let us all know how you got on!! 🙂

  13. Hi…
    I want2 find out if lactobacillus could be used in BIO GAS fermentation processes.
    Big thank for share this knowledge!

    1. I think it can. If you search “anaerobic digestion biogas” you’ll find more.
      Some good videos on youtube as well 🙂

  14. can I ferment 100kg cabbage leaves without water? if yes how possible to get enough liquid from the fermentation.

    1. Did you try?

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