I don't know why you would even consider that it would not be safe for your plants. I think that since it has no smell (or if it had an earthy smell) then that is a very good sign. If in doubt, you could dilute it immediately before application.

Is it a good idea to expose it to the sun? Would the UV rays kill any harmful bacteria or whatever? Is this liquid always produced during composting?

1) not necessary

2) they could but very doubtful there are any harmful bacteria there

3) yes, but one typically doesn't see it with a conventional compost 'pile' - it dissipates into the ground.

That "leachate" is created because the material being composted is too wet. Add some dry material to the mix in the tumbler and the "leachate" will disappear.

Is it harmful? No more so than compost tea. Will it have harmful bacteria in it. No more so than compost tea, although the material in the tumbler would be in anaerobic digestion with that much moisture.

kimmq is kimmsr

Liquid formation - leachate - is a natural by-product of the composting process. It occurs regardless if the compost is dry or wet. Ideally, you want to be in the middle of the road - the material should be just moist, like a wrung-out sponge - and neither too dry nor too wet. But leachate will form regardless.

Total nonsense, GardenGal. The only reason there would be drainage, leachate, from any compost pile is because there is too much moisture in the mix.

kimmq is kimmsr

In the desert southwest where there are quail, we see a vivid illustration of how condensation can occur with practically no water in the surroundings. Folks put up metal roofing panels slanted downward on wooden posts. At night, the air which might have been at single digit relative humidity during day cools, and the roofing panels cool faster than the ground so dew forms on them first. The dew flows down the panels to gutters at the base which collect a lot of water which the quail (and other wildlife) use to great advantage.

Renais

"Total nonsense, GardenGal."

Really?? Then perhaps you should take your great knowledge to institutes of higher learning because they haven't quite gotten that message. To the point where doctoral dissertations on the chemical and physical properties of compost leachate are being prepared.

"When water percolates through compost waste, it promotes and assists the process of decomposition by bacteria and fungi. These processes in turn release by-products of decomposition and rapidly use up any available oxygen, creating an anoxic environment. In actively decomposing waste, the temperature rises and the pH falls rapidly with the result that many metal ions that are relatively insoluble at neutral pH
become dissolved in the developing leachate. The decomposition
processes themselves release more water, which adds to the volume of
leachate."

If you think about it logically (and biologically), a lot of what is included in compostable materials has a high water contest - kitchen scraps, plant parts, grass clippings, animal manures (if part of the process). A well constructed compost pile - not too dry and not to wet - will have a moisture content of about 60%. And many/most composting operations are exposed to the elements. All that liquid has to go somewhere. What isn't evaporated - and in a well managed pile, that accounts for about 15% - forms a leachate, as a much a by-product of the process as it is a natural occurrence. And sometimes to the point where leachate management is a necessary part of the composting operation, particularly with regards to large commercial composting operations. But leachate occurs with even tiny, backyard operations as well

But then kimmsr, with your superior knowledge you should probably inform these PhD candidates and those who manage large composting operations and must answer to government authorities that they are full of nonsense and are really not doing it correctly.

Note that the decomposition processes involved in composting release CO2 and water in copious quantities. For an example of an extremely well documented study of the inputs and outputs, see http://www3.imperial.ac.uk/pls/portallive/docs/1/33729698.PDF and other related parts of this Imperial College multi-year study. One example of the data (treatment 3 in the study): Input was 20% yard waste, 80% kitchen waste. Composter was a small barrel. All inputs were carefully weighed, and output weighed and analyzed. Input was 49 kg dry matter, 176 kg moisture. Note that this is the moisture inherent in the inputs, not additional added water. Moisture lose was 111 kg. Moisture content of the final compost was 64 kg, with 18 kg dry matter.

The full study, available at http://www.imperial.ac.uk/environmental-and-water-resource-engineering/research/ecwm/ has a huge amount of data on various input streams, including very dry materials such as paper. Note in particular the lose of dry matter weight. That dry matter decomposed with the release of CO2 and water as byproducts; that additional water production is in addition to any water initially present in the material.

Renais

Hmm. I wonder if corn stalks release leachette? :-)

Why does everything here turn into a *peeing* match?

RD, to settle the discussion here, that stuff is possibly toxic, dangerous and detrimental to any plants. Bottle it up, ship it to me and I will dispose of it properly...

"Why does everything here turn into a *peeing* match?"

Not a peeing match at all. Just a correcting of misinformation that is routinely dispersed by a few regular participants that should know better.

ryan has given new meaning to "lowcountry"

i watched him call a senior member names when he doesn't agree with what you have to say

As for 'harmful bacteria', keep in mind that soil itself has millions of bacteria per teaspoon (or billions, even). Some of them are not particularly good for your digestion. The compost pile has even MORE microbes, which is how compost works. The key factor is, we don't eat soil or compost. So yes, the leachate is loaded with microbes. If it's not stinky it can be used around plants as liquid fertilizer. If it's gone anaerobic - as it likely has in your stored bottles - it can be harsh on plants the same way dog poop can kill a patch of grass until it is exposed to the air for awhile (then the grass grows back with a vengance). If it's gone anaerobic it should be diluted and maybe don't get it on the leaves. Ma nature will take it from there. Don't save up the stuff, it's most nutritious when fresh.

toxcrusadr, is it better to leave the bottle open so that air can get in? I have to store it now because I won't be planting until early June. There are plenty of bugs that got drowned in the liquid. Will they be decomposed? What's the best way of storing it?

Who is Rambo D? Guy knows nothing of what he speaks of....

i assume that R D is a seperate individual... Ah figured it out! This dude is a "senior member" with a sarcastic attitude who speaks in generalities without any wisdom. Platitudes, if you will.

Alias in the hizzouse.

Perhaps we can conclude that whatever the cause leachate is prob not a good thing esp. in a closed container. And likely indicates the tumbler (container) will soon go anaerobic.

Way back in the 1960's when I started making compost I had liquid flow from my compost until I spent time and effort on thje why and found that an excess amount of water in the mix was the cause of that leaching. When I found out how to properly out my compost piles together, with just enough moisture to satisfy the bacteria that digest the material, there was no liquid flowing from those piles. There should not be and if there is it is because there is too much moisture in the mix.

The cause of leachate from a compost pile, whether from a tumbler or any other source, it will be because there is too much moisture and that is not a good thing.

kimmq is kimmsr

To the OP, I would not recommend storing that stuff at all. Use it now, either on existing plants (shrubs, trees, perennials) or add it to the garden where you're going to plant later. The microbes will convert some of the nitrogen to gases which will be lost, and as they digest up the dissolved organic material they will die off, and will not be available to join the soil food web. Just pour it somewhere now, would be my advice.

And if you are adding water to the tumbler, it sounds like you can cut back on that a bit. :-]

I have never added water to the tumbler. If I decide to add it to shrubs and trees. Should I dilute with water it? If so, how much?

According to kimmsr you are mismanaging your composter with all that water you didn't add. :-P

I doubt you have gallons and gallons of this stuff so with shrubs and trees you might be able to just spread it around as is. If the plants are small and delicate and/or soil is dry so it will not spread out and dilute in the ground, you can dilute with up to 10x water. After that it's diminishing returns.

from my experience, if your compost bin is leaking then you are adding too much water, either by adding it, or what falls from the sky. i have several compost bins, including a tumbler, and I've never had any liquid leak out of it.. if anything, i have to add water to it to keep the tumbler moist. the materials i compost are shredded oak leaves and kitchen scraps (used coffee, egg shells, fruit and vegetables peels).

Well, everyone says something different. It's possible that rain has leaked into the compost tumbler, but it hasn't rain for about a week now and it's still leaking compost leachate. I noticed that when I turn it, more of it comes out. I'm going to add more dry browns tomorrow and see what happens.

Certainly, adding more leaves, cardboard, paper (shredded or just crumpled), etc should help.

Seems to me that if liquid is seeping at a rate fast enough to be captured in a vessel, its way beyond being too wet. Or either it isnt getting mixed often enough to be incorporated into the mix. In other words the liquid has enough quantity and time to flow by gravity. I suggest leaving the lid open for a little while to allow some evaporation, only closing it to "tumble" the contents. But I would also turn it several times a day to expose the moisture to the surface. If that does not get your moisture levels back in line, i would spread the compost out on a tarp for a day or two to increase its surface area to air exposure and then put it back into your bin.

I have an open pile now and do not use a tumbler anymore because my first year trying it I could never get a consistent "wrung out sponge" consistency of its contents. If rain comes and i do not need the moisture addition, i cover the bin with a tarp until the storm has passed.

just my .02, take it for what it costed you.

"According to kimmsr you are mismanaging your composter with all that water you didn't add". Tox, you have misinterpreted, and misrepresented, what I wrote.

I have gone back and reviewed the literature on liquid leaking from compost and do not find that anyone with a PhD thinks leachate from a compost pile is inevitable. What is written is what to do if you have liquid flowing because they consider that to be a pollutant.

Perhaps this from the manufacturers of the Hotbin Composter may be of some help in understanding.

http://www.hotbincomposting.com/blog/what-is-compost-leachate.html

Liquid, leachate, flowing from a compost mix is not a good thing and should not happen. Liquid, leachate, flowing form a compost pile is a sign the material has too much water in the mix.

kimmq is kimmsr

re:" leachate from a compost pile is inevitable."

this op is asking about leachate from a tumbler which is a closed container that most likely does not have enough air flow

"Well, everyone says something different."

Welcome to the SC&M forum. Where opinions become "facts" and "facts" are often distorted by personal bias. Good luck sorting out who to believe.

Keep in mind that when performing a process with so many variables, of course you are going to have different experiences. One person's fact can be vastly different from another person's. It doesn't mean one is right or wrong, it's just different experiences. One person is using leaves, the other cardboard, another uses both. Disagreements are going to happen. Think about the word moist... or that scientifically defined measurement of 'a wrung out sponge...' Seriously, there are going to be different experiences, different outcomes, and disagreements. Such is the way it is...

Some good advice above about adding some dry material and leaving the door open (at least in dry weather).

As for leachate - essentially liquid fertilizer - being a pollutant, well sure, if it gets into waterways. Many desirable things are pollutants in the wrong place or at the wrong time. Lemonade is a pollutant if I dump it the stream. The point is, 'desirable' and 'pollutant' are not the only choices. It's not a catastrophe if some leachate comes out. Observe and adjust your compost accordingly.

BTW it's possible for compost to be very wet but not short on browns, so the addition of browns may dry things up but can also throw the C:N ratio out of balance. Just fyi.

Compost that is too wet does not have enough air in the mix for the aerobic bacteria to function so what happens is anaerobic bacteria go to work and they can produce vile odors that should tell someone there is a problem.

Compost being too wet has nothing whatsoever to do with how much browns are in the mix, although adding dry browns may help restore the balance to the mix.

As the article from the people at Hotbin states some leachate may, about a cup, be produced, but a stream of leachate form any compost operation is a sign of a problem that needs correction.

Gardengal stated, correctly, that compost should be about as wet as a well wrung out sponge and that is not wet enough to produce any leachate.

kimmq is kimmsr

I'm not sure if my compost has gone anaerobic because it is very warm even though it's cold outside, especially at night. Yesterday, before adding more browns, I noticed that steam was coming out of it. It has a bit of a smell, but definitely does not smell like rotten eggs.

It is possible that maybe I had added more greens than browns. After adding the browns, there wasn't any more of leachate leaking from the tumbler. I will check again today. The lid is open, too.

If it's hot that means it is cooking well and has plenty of air. If it doesn't smell bad it's cooking aerobically and that's perfect. Actually it is not that easy to get a tumbler to heat up because they are not very big. You're off and running! Now check it in a couple days and make sure it doesn't dry out too much. All that steam coming out may (or may not) lead to dryness.

I know I keep banging on the same subject, but here I go again.

During the decomposition process, short chain organic acids are created - acetic, butyric, oxalic, etc. These acids are intermediate chemicals that eventually are consumed in the process of creating long-chain humic and fulvic acids (humus). These short-chain acids inhibit germination of seeds and growth of roots.

The leachate likely contains these acids. If possible, I would pour the leachate back onto the compost. If the compost is already too moist, consider applying the leachate to some future compost stock; leaves, grass. Otherwise, I'd apply it to soil away from sprouting or growing plants. Eventually they will be converted into humic acids and nourish the soil.

Thanks for posting the question. The discussion it provoked has been interesting.

Paul

Some have described the odor from an anaerobic compost pile as that of rotten eggs while others describe it more as raw sewage, but if the material is composting anaerobically it will not heat up since that digestion is done in the absence of air and the most common cause of that is a too wet mix. Too much water in the mix excludes air.

But once again, liquid (leachate) flowing from a compost pile is not normal and will only occur if the mix has too much moisture in it. That, excess water, sets the material up for anaerobic (in the absence of air) digestion.

A properly built compost pile should only have an aroma of good rich earth from the beginning to the end.

kimmq is kimmsr

I shouldn't split hairs but an anaerobic pile can be hot. Or more precisely, a hot pile can run itself out of air and be hot and stinky. Just make a pile with too many fresh grass clippings and you'll see what I mean. Sort of a special case though, not suggesting a small pile or tumbler that has gone anaerobic will always be hot. Usually not, at least for very long.

Just for kicks I will also include here the bizarre case of the Bridgeton Landfill in St. Louis, which has undergone a 'runaway anaerobic thermal decomposition' which the state regulators prefer to call an 'underground smoldering event' and the media likes to call a 'fire'. It is not a fire, but more like a very hot compost pile, without air. Runs about 200-300F and makes the most bizarre God-awful stink. I suspect there are some purely chemical reactions going on down there at those temperatures too. I mention it here only for the wow factor, not to suggest it has anything to do with a home compost pile. It would not really be possible for this type of thing to happen anywhere other than a landfill. It has happened at several landfills though. Ironically they think the root cause is pulling too much of a vacuum on the landfill gas collection system, to control odors, which pulled air from the surface down into the trash, creating essentially a huge hot compost pile, which then went anaerobic. It was able to sustain itself due to the excellent heat insulation provided by the earth, allowing the high temperatures to persist. This nightmare is one reason to minimize our use of landfills. Republic has spent over $100M on it over the last 5 years. Not even exaggerating. Speaking of the thread title...dark liquid? About 200,000 gallons per DAY of leachate.