Leachate friend or foe

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WillyWorm
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Leachate friend or foe

Post by WillyWorm » Tue Jun 13, 2017 7:46 pm

Somebody in another thread ask about leachate. I felt it was a big enough subject to have its own thread. Please pass on your experience of using leachate and any information you have on it.

If you visit any worm/vermiculture site or read any book or magazine article related to the subject of vermiculture then you will see a great deal of discussion on leachate. It's a very hot topic at the moment. The opinions expressed are very far ranging, sometimes, very contradictory. Well known and well respected worm heads hold very different views on the usefulness and safety of using leachate. Some say it's a valuable plant food, others say use with caution and some say it's dangerous and should not be used directly on or near food crops. 
Firstly what is leachate? To start with it's not worm tea nor compost tea nor casting tea these terms refer to a liquid which can be made from the compost/casting from your worm bin when they are mixed with water and re-oxygenated by stirring manually or with the help of a fish tank pump. Leachate is simply the liquid which got into your bin from from "wet" food or the environment i.e. rain or excess water being applied deliberately or by accident. This moisture perculates down through the trays collecting nutrients and microbes (some good and some bad) on its journey  and you collect it via the tap in the sump. It is sometimes called "worm pee" but none of it comes directly from the worms. You would get the same substance if there were no worms in the bin. There is no disputing the fact that leachate can contain a lot of nutrients and goodness. However they can contain some nasties, the liquid which passes through the bin can be anaerobic and in this anaerobic soup bad bacteria and pathogens can breed, these baddies can harm and even kill plants and can result in health problems for us. The big problem is the fact that every batch of leaches is different even when taken from the same worm bin.

George Pilkington in his book "Composting with Worms, why waste your waste" states on page 61 "I have heard it called "worm tea" by so-call experts. He goes on to say pour the leaches on the compost heap.

 Bentley of www.redwormcomposting.com says the jury is out on leachate.


Mary Appelhof in her book "Worms Eat My Garbage" acknowledges that some people use leachate to feed plants but makes no other comment.

Jeff Lowenfels and Wayne Lewis in their book "Teaming with Microbes" say leachate from compost adds little to the soil food web.

Worm bin manufactures and web sites selling worm bins claim leachate are a valuable liquid plant food.  

Huy from TheLittleWormFarm.com states "Using leachate that leaks at the bottom isn't pointless but risky" he goes on to say "the long term wetness (which results in leachate) will potentially create an anaerobic environment where bad bacteria can breed"

In my opinion there is some good stuff in leachate but it needs treating with caution. I set some rules some time ago. 
1) Avoid them, I manage my bin in a way which reduces the production of leachate. 
2) If I get leachate, and I do sometimes,  I check the smell, if they smell bad I dump them.
3) I aerate them before use. If it's a small amount this is a matter of putting them In a six pint milk bottle and giving them a good shake, larger amounts are put in a bucket and an air-stone connected to a aquarium pump is added to aerate for six hours. 
4) dilute at least 12 to 1 with water (1 pint to a standard 1.5 gallon watering can) before use.
5) never water over plants.
6) use around flower and ornamentals, rarely use near edibles never near edibles which will be eaten within a month.


Hope that helps 
Willy
My big concern about leachate is that it is taking goodness from the finished casting. There is only a finite amount of goodness in the food and bedding we put in the bin if we allow it to be "leached away" the finished casting will be poorer for it.

Willy
Last edited by WillyWorm on Tue Jun 13, 2017 7:46 pm, edited 1 time in total.

elleyfant
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RE: Leachate friend or foe

Post by elleyfant » Thu Jun 15, 2017 8:50 am

Doesn't George Pilkington say he puts it back in his wormery unless it's too wet, in which case he throws it on the compost?

I've found if I collect regularly by tipping the bin forward to drain as much as possible, it's odour free and I dilute and use on my plants. It's definitely done them good. I haven't given it to root veggies, but not for any reason other than I am more inclined to feed the tomatoes/chillis etc which are in pots so more likely to need feeding. But, more recently I've been collecting it less frequently, and I think this gives the anaerobic bateria time to breed. It has an odour and it goes on the compost heap just to be sure.

I'm totally with your first point though. I just haven't managed to prevent them yet!..

WillyWorm
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RE: Leachate friend or foe

Post by WillyWorm » Thu Jun 15, 2017 7:29 pm

Hi, your right about Pilkington putting it back into the worm bin but in my opinion if you do that then there will never be dry bedding to absorb any new moisture and more leachate will end up in the sump even quicker.
I checked the sump of two of my bins today and got a total of 3 fl oz, that was three weeks after they were last emptied and I did tip the bin. ?

elleyfant
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RE: Leachate friend or foe

Post by elleyfant » Fri Jun 16, 2017 7:56 am

I don't see how I would ever think my bin wasn't wet enough! It is plastic though and I understand he has wood ones, so maybe that makes a difference?

WillyWorm
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RE: Leachate friend or foe

Post by WillyWorm » Fri Jun 16, 2017 8:34 am

I would think that the case. Also his bins are much bigger.

greenfingerswannabe
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RE: Leachate friend or foe

Post by greenfingerswannabe » Fri Jun 16, 2017 10:01 am

Morning Willy

Great write up and as you say, the debate continues. I will add as and when I have experience of leachate, but, that of course, will be some months away.

OT 

I made my own very organic pesticide this year from rhubarb leaves and very successful it seem s to be. I put the boiled residue in my compost bin, but now I have a wormery, I just wonder if it would be to their taste?

Alan

WillyWorm
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RE: Leachate friend or foe

Post by WillyWorm » Fri Jun 16, 2017 3:26 pm

If it is just boiled up rhubarb it should be no problem. I put shreaded rhubarb leaves in my bin from time to time and the worms seem to love them.

WormyMcWormerson
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RE: Leachate friend or foe

Post by WormyMcWormerson » Fri Jun 16, 2017 3:37 pm

Generally I collect 1 litre of leachate a week, which is about right since I feed 1.4 kg a week and fruit/veg scraps are 70% water or more. The only way I've found to reduce leachate when I feed this much is to leave the lid off. Not that I want to reduce the leachate: it's filtered through at least 3 trays of castings, doesn't sit in the sump for more than a few days and the worms like to wallow in it. It would be interesting to see a chemical and biological analysis of different leachates to support or refute the opinions of the experts, but for now I'm quite happy to use it (if it doesn't smell and diluted by about a half) on anything in the garden, including edibles.

Dynamo
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Re: Leachate friend or foe

Post by Dynamo » Wed Jan 24, 2018 2:36 pm

How can you tell the difference between leachate and proper worm tea? The stuff from my wormeries is always dark brown, this could be because I put a lot of coffee grinds into it, but doesn't smell. I did notice that I was getting much more after a rain shower so I assumed that rainwater was getting in. Since then I've put a cover over the bins to keep the rain off and so far haven't had any tea from them, though I only cleaned them out a few days ago when I first put the sheet over. I've been putting most of the juice into my compost bins but I have used some of it on plants with no detrimental effects as far as I can see.

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wormcity
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Re: Leachate friend or foe

Post by wormcity » Thu Jan 25, 2018 1:47 pm

The Leachate is the 'run off' from the wormery.
Basically the liquid from the fruit and veg which accumulates in the sump

Worm Tea is made by putting the vermicompost into a porus bag and leaving it to brew in water.
Many people bubble air through it as well

Some people say that leachate is dangerous when emptied out from a wormery, but I don't think in the 12 years I have been selling wormeries I've ever had a person say it has NOT be good to their plants.

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