Organic Broad-Spectrum Herbicide Recipe (Wild-Foraged from ‘Weeds’)

Organic Broad-Spectrum Herbicide Recipe (Wild-Foraged from ‘Weeds’)

Chemical warfare isn’t something generally associated with plants – they are more associated with peace & serenity, harmony & working in community (the colour GREEN represents LOVE).  The truth is – just like people, not all of them are kind.  Taking a little time to observe what species are dominant & by how much can uncover a grisly tale – for plants, that is!  Allelopathic species are genocidal, literally!  Translating as “causing those with different genetics to suffer”, these green-ones are nasty!  By releasing growth inhibiting substances into the soil they kill all other species – up to 100%.  They are killer-plants…and develop natural monoculture worldwide.  Ever noticed how Australia is covered in almost nothing – but eucalyptus…or how camphor laurel can take over a river system in just a few years…or how amaranth is so easy to grow?  Yes, you’ve got it – it’s because everyone else is DEAD!  Killed by these murderous allelopaths.


So, what do we do with these guys?  With an ironic flip of the coin – do WE become the genocidal killers & pull THEM out?  Or just let ‘em grow & hope for the best?  Well that depends on your garden needs.  If you don’t need that space – why bother doing anything at all (just let nature take its course).  But if you need that space, why not harvest them as a crop.  Just think about it – they contain a substance which can kill plants.  They are a NATURAL BROAD-SPECTRUM HERBICIDE.  So how exactly do we do this?


We can release the target allelopathic substance held within the plant cells by freezing which will burst the cells open.  Ensure the whole plant has been shredded into small pieces, add water then freeze + thaw up to three times.  On the third defrost, blend & strain the solids out  (make sure all seeds are destroyed in the blender).  Voila – you have a solution of naturally derived & locally foraged broad-spectrum herbicide.  Just like any plant material, keep it fresh by storing in the fridge (for up to three weeks) & freezer for long term storage (no limits here, keep it for eternity if you like).  Be sure to label clearly as you DON’T want to get this stuff mixed up with your Kombucha!


So how much should we use?  A study done in Japanese rice fields found the optimum application rate to be around 100 grams per square metre when applied 1-5 days at the start of the growing season (2).  In other words – the seed won’t sprout & the plant won’t grow.  Let’s round this off to be ¼ – ½ of a soft drink bottle in liquid extract.  Transfer to a bottle & use as a foliar spray directly onto the flowers or seed of the unwanted plants or pour into a watering can & soak into your garden soil (where the unwanted seed would generally sprout if left untreated).  If you are planning on using over a large area – you may wish to trial on a smaller plot first.  Happy killing – I mean, gardening!


This is ORGANIC GARDENING at it’s best!



For more information download:

“Allelopathy an Environmentally Friendly Method for Weed Control”


Or follow a research project on this topic by Harper Adam’s University, Kurdistan Region Government and the Ministry of Higher Education here:

“Weed control using allelopathic plant species”




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Chrissy-Tiina Laurikainen

In person + online permaculture teacher. Online permaculture consultant. Upkeep of a 30 acre rural property (using permaculture & other agroecological techniques). A communal research laboratory focusing on free innovation in the works. Doing what I can to support LIFE on planet Earth!!

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