Using Worm Bin Leachate

An interesting question from Jake:

I am confussed. I see people s[ell] worm tea and stuff and
that is the reason i bought a [w]orm factory thing. But the other day i
drained a little bit of the worm tea mixed it with a little bit of
water and sprayed it on my plants. My pomagrante tree it seemed over
night got these yellow color to some of the leafs?

Is there a wrong way to use the worm tea? i even saw one website that
said it was toxic and not to use the worm tea liquid on plants. What
is the deal?

Hi Jake,
This is an excellent question – thanks for writing in.
I’ve written about this topic numerous times, but it’s definitely one that deserves to be revisited from time to time.

Unfortunately there seems to be misleading information provided by some worm bin manufacturers (and website owners). The terms ‘worm tea’, ‘worm compost tea’, ‘castings tea’, or ‘vermicompost tea’ should actually refer to the liquid fertilizer created by steeping (soaking) quality castings/compost in water (often aerated) for a period of time. The problem is that many people refer to the liquid that drains out from a worm bin as ‘worm tea’, when the proper term for this is actually ‘leachate’.

Obviously, we’re only talking about words here so it probably seems like I’m splitting hairs, but keeping the distinction between these terms is actually quite important. While leachate can certainly have value as a liquid fertilizer (especially when drained from a mature worm bin), it should be treated with a lot more caution than good quality worm tea. As water passes down through a worm bin it can pick up all sorts of unstable metabolites (various products/intermediates of the decomposition process) – if for example, you can some fairly anaerobic zones in your worm bin, you can end up with various phytotoxic (plant harming) compounds in your leachate.

Finished composts are much better to use for worm tea creation because they are much more uniform in composition, and the vast majority (if not all) the potentially harmful compounds have been converted into something more stabilized. The microbial community present in these materials tends to be more beneficial as well.

Again, I’m not trying to say that leachate is “poison” and should never be used – I just recommend taking some extra steps, or at least using it with caution. I would probably dilute it and aerate with an aquarium air stone before using it myself. You can probably get away with using it outdoors and with hardy plants, but I certainly wouldn’t recommend putting it straight on houseplants or using with plants that tend to be a little temperamental.

Anyway – I hope this helps to clarify things for you a little, Jake.

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    • Richard Blalock
    • July 18, 2009

    When the original bedding in my wormbed had been processed (I say processed, but I think it probably could have gone a little longer without changing) for a period of about six or seven months– (it’s about 3′ long, 2′ wide, and with about 12-15 inches of bedding [I believe I’ve read that with a smaller system it only takes around 3 or so months to process when worm population is at capacity])– I started to use the lechate as the only fertilizer for my beefsteak, pink brandywine, and grape roma tomatoes. It works excellently (however the soil they were/are in has been processed and amended with grass compost and other things for over a year); the tomatoes my brother and I have grown this year are better than we’ve ever grown. However, I’ve NEVER sprayed the lechate directly on the leaves, and I did mix .5 gallons of water to every 1.5 gallons of lechate. I started with a 1 gal. water-to-1 gal. lechate mix, but then decided to try 2/3 lechate and that worked a lot better (however, all bins and beds are different and I wouldn’t advise going higher than a 1:1 ratio until you’re sure that it’s not hurting the plants). As Bentley said, though, be extremely careful when dabbling with the lechate. I know what it’s like to have nice, healthy plants just go kaput after watching them grow to fruition (early blight is a terrible thing). If it caused the leaves to get yellow spots, it’s probably best to apply at base of plant. However, to be on the safe side I would try it on plants that are a little more negligible to you. But the best thing I’ve done this year was to grow hot peppers in pots and mix worm-compost up in their soil. Hope this helps at least a little! =-)


    • Rich A.
    • July 20, 2009

    I killed a flowering cactus with some leachate, so it can harm plants. I dilute it now, and haven’t killed anything in an outdoor flower pot.

    • Bentley
    • July 22, 2009

    Thanks for sharing all that, Richard! Very interesting stuff. Glad to hear that your tomato growth experiments have gone so well.

    • Kelly
    • April 7, 2010

    Interesting, I was excited when I harvested my leachate thinking it was something good for my plants. I diluted it, put it in a spray bottle and added it to my starts. It didn’t kill them, but it didn’t seem to help them much. So here I am do some research of leachate and I am finding that is can be very harmful to plants.

    I went to my bottle of leachate and opened it outside (it smells like fart, really bad “omg i ate too many beans” fart), and there was some pressure. So this is alive, so I decided to add some molasses and shake it. I will see what happens in a few days (the lid is on, but pressure can still released, imagine that bottle exploding, oh the smell), but I am more interested in adding it to my compost pile then my plants.

    Do you have any ideas on using leachate as a inoculate of microbial activity? Perhaps it would be like adding EM to the compost pile.

    • Alex D
    • August 9, 2010

    I find this whole leachate conundrum rather perplexing, which is why I decided to do my own research and have just started my first batch of leachate derived tea. I am busy oxygenating just over a gallon of leachate after having added 1 tablespoon of blackstrap molasses. It smells perfectly fine so far. Once the 24 hour period is complete I will most likely dilute the mix down to 1 part leachate:3 parts water (dechlorinated) before using on my plants. I am looking forward to seeing the results of my little experiment!

    • Bentley
    • August 10, 2010

    Not all leachates are created equal – not even close. If your bin is fairly new, and you tend to overfeed it (creating anaerobic pockets), the liquid coming out the bottom likely isn’t great stuff at all. If your bin is mature and you are getting the hang of it (vermicomposting that is), it is perfectly reasonable to assume the liquid coming out the bottom will be reasonably good stuff.
    The only reason I get a little huffy about people calling leachate “worm tea” it can lead people to assume that vermicompost tea isn’t all that amazing – when the “real” tea truly can be.
    Any leachate that is then oxygenated and augmented with additives (molasses etc) has the potential to become “better quality”. As such, I wouldn’t be surprised if you find that your liquid works fairly well, Alex. Please do keep us posted!

    • Dan
    • October 18, 2010

    Been reading about Leachates to understand more about it, as good or bad for plants. As many people have come up with different results, Some good. My question to everyone is, What have you been feeding your worms? maybe just manure? Would that be the reason some have had good results with the leachate?

    • Dan
    • October 18, 2010

    I have only had my worms for 2 months. maybe I should test this theory myself by having 2 seperate bins feeding 1 just manure and the other regular vegies ETC. Take the seperated Leachates and apply to each to its own plants. Maybe thats why some have had good results. ITS just a guess But I like a good challenge. Please give me Your thoughts !

    • Dan
    • October 18, 2010

    Could this be something to test? maybe take 2 bins, feeding 1 vegies etc. 1 feeding just manure. take each leachate and feed it to its own plant for a while.
    Im just looking to see why some have good results with leachate and some have poor results. Do you think it will be a waste of time?

    • k
    • November 2, 2010

    I have four stacked bins 5-8 months old (never harvested). after recent heavy rains there was about a gallon of ‘leachate’ in the collecting tray (two days ago) to which i already added 3 gals of rain water yesterday and stirred it today. how do i proceed from here? i have blackstrap molasses and other additives at hand as well as an aerating kit. main question: for how long should i aerate before application; i presume soil drench is better than foliar spray as per above?

    • jws
    • July 14, 2011

    I now understand the difference after recently making compost tea with a brewer…totally different. However, previously I was diluting the leachate; 1 part to 10 parts water and using it as plant food, bottling it up and giving it to my garden friends. Have not had any bad reports, I have not hurt any of my plants, some more noticeably than others really took off. I was fairly confident that only very good things were going into to the vermicomposter anyway, and I spoke to someone at Water-Wise gardening who also told me that it was fine to use at the base of plants, close to the base of trees.

  1. I just read this article on Leachate. I’m planning on using an old Fiberglass Tub with a drain at the bottom to catch the worm juice. First I’m not sure if I should leave the bottom drain open or plumb it. Now I’m worried about the Leachate. Is it dangerous for my dogs? Maybe someone can take a look at my YouTube Channel and advise me. Thanks for sharing this information.

    • Michael
    • April 17, 2012

    I guess I must be almost the only person in “wormdom” who successfully uses worm bin tea or “leachate” with absolutely nothing but positive results. I built a worm bin in a 25 gal Rubbermaid Tote, drilled 5/16″ holes only in the sides and ends, NOT the top and bottom. Then installed a PVC drain valve in one end near the base of the unit. Then put a bag of gravel over the drain valve intake, filled with shredded paper & cardboard, some garden soil and kitchen waste and worms. I pour a 2 gallon watering can of water over the worm bin contents and quickly put the can under the spigot and turn it on to allow the worm bin to drain for an hour or so. PRESTO, quick, effective worm tea every day without brewing or waiting. I do this 2 or 3 times daily. Sometimes I use it immediately; sometimes I let it sit for an hour or three. Smells like a barnyard, mmmm good, can be poured directly over plants or onto the soil. Doesn’t hurt anything, just got rid of aphids and white flies and made everything grow great in my garden with absolutely no artificial fertilizer. Let me know what you think.

  2. Thank goodness that some people like you are giving the straight goods on this subject. Many sales type people have really messed this up.

    Tim Wilson ~ Microbe Organics

    • aleph
    • October 20, 2012

    I have a Worm Factory 360 for the last 5 months or so. The manual does say you can use leachate as a fertilizer. My device didn’t produce any for the first couple months and isn’t right now, but when i put a big load of veggie trimmings or used up soup veggies on there is about 8-12 ounces the next day. It has always smelled like clean to nothing, except one day it smelled bad.

    I don’t believe the people who say there are no nutrients in it, the deep brown color suggests otherwise. There may be toxins though. I put some on a hardy outdoor jalapeno plant (on the soil, not sprayed on) and I believe it was responsible for the plant going yellow and dropping its leaves thereafter. it still has a few marble sized peppers, but they havent matured, and the leaves didnt come back. (luckily these jalapenos are 10x hotter than store bought, so the other plant more than supplies my needs). I tried it in a pot of variegated cat grass and california poppy sprouts as well (half strength, I think). It killed the white phenotype of cat grass while leaving the cali poppies and green phenotype grass untouched. I have put it in the garden ~ 6-12 inches from plants without ill effects, but mainly now just dump it on my overflow compost (i produce far too much coffee/tea/herbs tea waste for the worm factory).

    Thought I would add my experience to increase the wisdom of the internet. This is my first year gardening. Have started a rubbermaid worm bin, but just barely, as well.

    • TXdurk
    • February 25, 2013

    If leachate is potentially a problem, what do you do with it? Can it be used without harm as an ingredient in a brewed worm casting tea?

    • k
    • February 26, 2013

    the main concern w/ leachate is its anaerob makeup – most human pathogens are anaerob. a tablespoon of molasses and 24hrs active aeration takes care of that. if you don’t have an air pump, just adding it to a ‘hot’ compost heap, feeding to ornamentals, or anything that’s at least a few weeks away from harvest is ok. the root system of plants can protect the plant and the indigenous wildlife will quickly consume the intruders if your growing medium is aerated. both diluted and full strength is safe; there are no nutrient lock-ups with worm manure. don’t use anaerob leechate as foliar feed.

    • TXdurk
    • February 26, 2013

    Thank you K. I’ll dilute it, aerate 1 day, add molasses, and use on ornamental shrubs. Just hated the idea of losing anything I could ultimately use in a permaculture way. I’ll also brew a similar tea without leachate using worm castings for the root systems of my fruit trees. Thanks again. Regards.

    • corinne day
    • April 20, 2013

    my munincipal water system uses cloroamine in its sanitation process which cannot be removed by standing out in the open air. i need to use something for removal when i add it to my aquariums will this harm the worm tea’s microbes. thanks

    • Brian Joffin
    • August 25, 2013

    Just started a wormery in back of my apartment block. Inherited two drums of leachate that I’d like to distribute as plant food..can I add liquid EM? Or is the molasses addition and 24 hour aeration sufficient? And for how long does it “keep” its properties then?

    • Laura
    • December 26, 2013

    Thanks for this clarification—I, too, thought (leachate/’worm juice’) was the ‘liquid gold’ red worm composters spoke of. Now i know otherwise. Yes, always good to revist topics (for us newbies). Thank-you.

    • Christina
    • July 14, 2014

    Hi! I just thought I’d add my two cents. I always distrusted leachate due to its reputation, but this week my zucchini plant started looking like it was on the way out (I suspect PW), and seeing as how I’d been out of my regular fertilizer for months (I mainly use worm castings, mixed in the soil or dressed on top, but for quicker release feeding I use happy frog’s 555), I figured what the hell… At best it’d buy it a bit more time, at worst it’d kill a plant already on it’s way out. A few days after I added a bit to the soil/roots, my plant (which had only yellowish, bright yellow/Burnt looking leaves) had multiple emerald green shoots/leaves, some have already grown quite substantially… I could not believe it!! Needless to say, this has influenced my opinion of leachate quite a bit, and I see more regular use of it in the future. 🙂

    • Christina
    • July 14, 2014

    Also, fwiw, I used only about 1/4 – 1/2 cup of the stuff, undiluted. The zucchini is in an outdoor, seven gallon smart pot. 🙂

    • Mokcy
    • August 25, 2014

    In the worm factory 360 website it explicits says to use this stuff with caution and with plenty of water, that alone should tell you its toxic.

    And for those reading the comments here, it also says that you should never use leachate when it smells bad.

    If you own a worm bin why even take the risk? I mean, if you have a worm bin you probably have or will have work casting eventually and creating compost tea out of it its not hard or difficult.

    Personally I don’t think its worth the risk and killing or damaging your plants and you should trow away any leachate that comes out.

    • Chris
    • November 12, 2014

    I have always put worm farm leachate undiluted 100% directly around my citrus trees. It gets poured on about 3 litres at a time and I put it around the edge of the drip line. The trees give huge and heavy crops twice per year and it is very common to have it fully in flower while the previous crop is still on the trees. Leachate may well be risky for some plants but I can’t give enough of it to citrus. I never put it directly on a plant and all I do is collect it and pour as soon as the container is full enough to make it worthwhile. My experience could not be more positive. If you have lemons or limes or other citrus, it may be a small test..

    • Cedar
    • January 24, 2015

    Whhhhhhat?!?! I never knew citrus gave fruit twice a year?!?! Im from a temperate climate. And new to all subjects- besides the passion of eating fruit and sometimes shedding a tear when i eat a new one. … Man. you guys sure have it good in the warm places dont you! 🙂

    • Chris
    • February 8, 2015

    We are in New Zealand, climate is never really hot and never really cold. Surrounded by ocean we approximately follow the sea temperature. I guess cropping twice a year means they are really happy trees. But they never did that before getting the leachate. So, for an old tree that has packed up or for a small test, I recommend you give it a try along with normal food and water.

    • Mie Kaul
    • July 24, 2015

    I’m new to all this but started my own worm farm with flo-thru system bin I made. I have great success with them and now have three. Don’t have leachate yet but when your bin smells and gives leachate then they are toxic and recommend throwing it out. My worm farm has been thriving and smells earthy all the time. In time I hope to have clean leachate for my plants.

    • Jeremy
    • August 16, 2016

    I wouldn’t throw it out but try and save it somehow, when your bin starts to smell, in my case i used to much manure and it really heated up the bin add loads of peat moss and halve it. That saved a lot of my worms that started to melt. Peat moss is definitely the best bedding I’ve seen and will use.

    • Lee Morais
    • November 30, 2019

    I been using LEACHATE but I have a reccepie that I’ve been using for a long time
    I mix my watering water In a 5 gallon can.
    With my other nutrients I add only 3 table spoon of this liquid gold.
    All my plants are super super

  3. Make sure to aerate and get an accurate/alter pH reading of your leachate and you’ll never kill anything again. My Worm bins tend to lean towards the 5.5 pH mark. Use like cautiously for a neutral 7 pH buffer. Your welcome.

  4. Edit for above post * use lime cautiously *

    • Teri
    • September 5, 2020

    I’ve been vermicomposting for over 10 years and have 36 bins going (6 worm farms with 6 bins each). Until this year I’ve just taken the leachate, diluted it 1:1 with water and used in the garden (mostly flowers). I just got hooked and decided to create the ‘real’ worm tea by aerating the vermicompost with a bubbler. It’s too soon to tell the outcome. BUT, I don’t want the worm LEACHATE to go to waste, so I’ve decided to create what I think might be the best of both worlds and combine the leachate into the aerating brew. Today is the first time trying but it seems to make sense that I can just aerate it along with the compost tea. Just a thought in case anyone is doing aeration. It’s not as complicated as it might sound

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