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I have a closed-bin compost bin (because of location/equipment, I don't have anything open and I can't tolerate the smell). My compost is almost entirely greens, now black and rotting (I didn't put enough browns).

Even though I'm starting to add browns, what confuses me is the water quantity. I put fresh greens (eg. orange peels) every day or two, and every time I look, I can see the bottom portion of the bin has liquid in it. I can see the liquid in it.

I'm trying to compensate temporary by adding more browns (shredded newspaper, dried-out weeds), but is there a deeper problem here? Is this normal to see water collecting at the bottom of my closed bin?

(It's a ~13 gallon dark blue plastic garbage can that I leave outside. I can move it into the garage if indoors is better for composting.)

  • I'm not sure what size, unfortunately. I think it's approximately 13 gallons, and it's outside. Question updated accordingly. – ashes999 Aug 16 '13 at 14:51
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    Anything kept too damp or with standing water, goes anerobic in those areas, releasing nitrogen and sulfur compounds. One depletes the compost of nutrients, and the other smells. You must keep it wrung-out damp and allow for air flow so aerobic bacteria are predominant. Anerobic-why sewage stinks, aerobic-why you can swim in rivers where some whitewater prevails. – Fiasco Labs Aug 17 '13 at 2:20
  • @FiascoLabs I suspect this is common with closed-bin composting; hence my question. – ashes999 Aug 17 '13 at 3:07
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Green plant material contains a lot of water that is released as it decomposes. The liquid in the bottom of your container is called "leachate". You can try drilling or cutting some holes in the bottom of your container to let the leachate drain out.

You need to add browns. Greens have more water and the nitrogen makes them compost faster. If you don't have enough browns you can try letting some of your greens sit out in the sun for a couple of days so they brown out before adding them to your bin.

Composting also needs air. If the compost bin doesn't get enough air the composting becomes anaerobic and starts to smell. If you insist on using a closed bin you should turn it to aerate.

  • How often and how much do I turn it? Should I leave the lid off? – ashes999 Aug 17 '13 at 18:56
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    @ashes999 Turning depends on a number of factors. Too many to go over here. Try reading this and other articles on composting. composting101.com/hot-composting-article.html Composting requires air. Leaving the lid off will help but drilling holes in the side is better. Adding twigs and other such materials that can leave air spaces in the bottom is the best because it allows air to come up from the bottom naturally. This is the composter I use. It has a lot of holes all around. diyorganiclawncare.blogspot.com/2009/06/… – OrganicLawnDIY Aug 18 '13 at 5:23
  • Thanks, I'll take a look when I get a chance. I thought weeds/grass count as browns, but it seems like thye're greens. Watery greens. – ashes999 Aug 18 '13 at 12:33
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    @ashes999 When the chlorophyll is gone from the grass, its N is reduced. Chlorophyll is Mg surrounded by 4N en.wikipedia.org/wiki/Chlorophyll#Chemical_structure As DIY said, if you let your greens dry out, they will be browns. – Randy Aug 18 '13 at 13:46
  • Sorry it took so long to mark this as the correct answer. I ended up drilling holes in my bin, which helped with drainage and aeration. – ashes999 May 6 '17 at 21:13
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It is ironic that closing up your compost because you don't want the smell is precisely what is causing the smell. You can compost in just a heap - a little pile of stuff in the far corner of your yard. If you want to confine things a mesh walled container with no floor lets air in and liquid can drain away. If you are worried about varmints, a mesh or slatted lid can keep them out.

At a minimum, make a bunch of holes in your garbage can - in the bottom to let the liquid out and in the sides to let air in. Aerobic composting smells musty and earthy. Perhaps not entirely pleasant (it's not like chocolate, coffee, baking bread, fresh roses) but not disgusting. Our bodies reserve disgusting for anaerobic decomp - sliminess, sourness, acrid smells. So if your compost smells wrong, get more air to it.

The other thing with composting is to ask yourself why you are doing it. Are you trying to make fertilizer for a garden, or to reduce the amount of garbage you send to the landfill/incinerator? Which is the primary motivation? If the latter, don't get too worked up about greens/browns, balancing things, adding stuff just for the sake of the composter etc. In our mesh bins (scaled down versions of the bins from the Victory Garden book) we put peelings and the like from the kitchen, carrot greens and other parts of plants we don't eat, weeds we have just pulled, and fireplace ashes when we happen to have emptied the fireplace, all without a plan: just as stuff becomes available, it goes in. We have never (20+ years) measured its temperature or chemistry in any way, unless you count smelling it. The only turning we do is that described in the book - you take compost from bin 3 whenever you need it, and when bin 3 is empty or bin 2 is full, you turn 2 into 3. Meanwhile when 2 is empty or 1 is full, you turn 1 into 2. 1 is where you add new stuff. Sometimes we toss a little dirt (or bin 2 or 3 contents) over the top of 1 if it's smelly.

This super hands off approach works great for us. We get compost for rhubarb, the veg garden, and the flower beds. We throw out almost no garbage. And we don't fuss about our compost. If you can adopt something similar, I think you will prefer it to a single closed bin that needs babysitting and looking after.

  • Not a bad answer, but essentially it's "change to open-bin composting." That's not something I can consider at this point. – ashes999 Aug 18 '13 at 22:08
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    @ashes999 I'm not even sure that "closed bin composting" is even a thing except for maybe bokashi (en.wikipedia.org/wiki/Bokashi_composting#Bokashi ) Some compost bins are more open than others but they all have to allow for air to enter the pile. As Kate mentioned the lack of air might be contributing to the stink problem. Why is it you feel you need a closed bin system? If it's because of the smell you would have less smell with better aeration. – OrganicLawnDIY Aug 25 '13 at 13:33
  • @OrganicLawnDIY I'm still learning as I go. I used a closed-bin because that's the biggest container I have, and some time spent googling made it seem like this is a viable option. It appears that closed-bin is more succeptible to stinking and anaerobic/slow composting. – ashes999 Aug 25 '13 at 14:24
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    @asshes999 I completely understand using what you have and jumping in and learning as you go. I hope I'm not discouraging you. If you have or can borrow a drill, a lot of holes in the bottom and sides would benefit the pile. Check out wholefoodsmarket.com/blog/make-trash-can-composter for an idea. For turning you can tighten the lid if possible and just roll it around on the ground. Better yet, dump everything out and shovel it back in. – OrganicLawnDIY Aug 25 '13 at 22:39
  • @ashes999 first HUGE apology for the typo in your name above! One more tip. If you can scavenge 3 or 4 bricks or cinder blocks you raise your bin off the ground a bit which can help air come up through the bottom holes you drill. Worms and other beneficial crawlies won't be able to enter so it's a trade off. – OrganicLawnDIY Aug 25 '13 at 23:43
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Here is where some of the water is coming from

C6 H12 O6 (organic matter) + 6O2 ---> 6H2O + 6CO2 + energy

Browns would slow the breakdown process, giving evaporation a fighting chance at reducing water accumulation.

Here is where the smell is coming from

C6 H12 O6 ---> 3CH4 + 3CO2

Without oxygen, you get methane (CH4), which stinks. Browns would slow the breakdown process, therefore requiring less oxygen per hour. Browns would also increase "fluff", absorb moisture, and let the pile breathe more.

How often to turn the pile?

According to their experiment, microbes can strip out the oxygen in compost within 15 minutes, there must be a constant flow of air through the compost, and far more than provided by passive aeration by convection.

http://microbewiki.kenyon.edu/index.php/Compost_pile

It's been well established that most of the oxygen added to a pile during turning is used up by the microbial populations within hours, or even minutes of turning. Therefore, unless additional oxygen is being provided under pressure (ie. via "forced aeration") or a pile is turned hourly, the purpose of turning is NOT to add oxygen but rather to restore pile porosity which allows oxygen and carbon dioxide to naturally move into and out of a pile through a process called "passive aeration".

http://www.cvcompost.com/in-defense-of-the-pile-less-turned.php

  • You mentioned evapouration. Even in a closed compost bin, really? – ashes999 Aug 18 '13 at 13:55
  • @ashes999 Yes, how else will water turn to vapor and leave the can? – Randy Aug 18 '13 at 13:59
  • I don't see how that's possible without leaving the lid off periodically (or permanently). – ashes999 Aug 18 '13 at 22:03
  • @ashes999 Wouldn't take answer the water-retention question? – Randy Aug 19 '13 at 4:18
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    @ashes999 I'm sorry, typo, that should have read, "Wouldn't that answer the water-retention question?" To remove the water, you can either drain it or let it vaporize and float off in the air. Adding more browns will slow the composting process and reduce the amount of water produced and allow more of the water to evaporate (especially if you leave the lid off). – Randy Aug 19 '13 at 10:51

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