If you’ve followed the blog for a while, or have at least spent some time perusing articles, the term “vermicomposting trench” will more than likely ring a bell. These in-ground vermicomposting systems quite literally opened the door to an entirely new, exciting world of vermicomposting/gardening possibilities for me – and I certainly haven’t been shy about letting people know!
Pretty funny when you consider how it all began…
In late spring of 2008, shortly after starting up my own worm composting business, I decided to get in touch with a popular local restaurant to see if they might be interested in giving me some of their compostable waste materials. As it turned out, the owner was very eager to sit down and chat about the possibilities, since this had been something weighing on his mind for some time. All of their organic wastes had simply been getting tossed in a dumpster up to that point, so he was certainly open to the possibility of exploring some environmentally-friendly (and hopefully less costly) options.
Long-story-short, thanks to a BIG dose of naive excitment on my part, and my ability to convince the owner (and even his rather cynical manager) that I knew what I was doing (haha), I left that meeting having agreed to take the ENTIRE composter-friendly waste stream (fruit & veggie waste, egg shells, and coffee grounds) off their hands – literally hundreds of pounds (and many garbage cans full) of material each week.
C’mon – it’s almost entirely water, right? No big deal!
Well, for the first couple of weeks it probably didn’t seem like such a big deal. I had lots of “food” for my worm herd, and I was getting lots of exercise outside, hauling bins and chopping up the materials by hand (with a shovel, that is! lol). Gradually my enthusiasm started to wane, however, as it became apparent not only that the project was going to require a HUGE time commitment on my part but, even more importantly, that perhaps my medium-sized suburban property might not be the ideal setting for dealing with all that organic waste.
After quickly overloading all my various composting/vermicomposting systems, and then many of my various empty containers, I went into squirrel mode and started digging holes all over my yard so I could bury all evidence of my unbelievable stupidity (haha)!
Eventually I even ran out of good spots to dig holes…but still, the wastes kept a comin’!
It literally got to the point where the stench of rotten food waste would hit my nose as soon as I stepped out on my back deck (to this day, I am amazed that I didn’t end up with a single complaint!). I knew that even if I DID pull the plug on the project (increasingly looking like an inevitable outcome), I’d still have to deal with a LOT of rotten material that was only becoming more foul with each passing day. I needed a drastic solution, and I needed it “yesterday”!
That’s when the trench idea popped into my head! I can’t remember for sure, but I would NOT be surprised in the least if my first plan was simply to dig a really deep trench and then bury everything – but regardless, I (thankfully) ended up settling on the idea of setting up the trench like a giant worm bin instead.
The rest, of course, is history!
I certainly won’t claim that my vermi-trenches ended up being the answer to ALL my waste troubles. As it turned out, I did end up having to discontinue my waste pick-ups in early September (only a few months after I began) due to time constraints and cooler weather (thus slower processing speeds). Still, just the fact that I was able to quickly take care of what would have become a much nastier situation, and then to continue on with the project for a few more months is nothing short of a miracle!
This doesn’t even factor in the positive impact the trenches have had on the adjacent garden beds (specifically, the plants growing in them)! I certainly haven’t conducted any rigorous scientific research, but I still think it’s safe to say that the trench systems have had a positive impact on my backyard plant growing efforts!
PROS of the Approach
1) Eco-friendly approach for fertilizing your plants while taking care of your organic “wastes”.
2) Can help to reduce the need for summer watering – especially when water-rich food wastes are used.
3) The system is quite well-protected against hot/dry and cold conditions.
4) Once set up it can be used for multiple seasons
5) No need to harvest compost
6) Can be a great way to handle lots of compostable waste materials
CONS of the Approach
1) Labor-intensive when first set up.
2) Not ideal for locations with high water table and/or potential for flooding
3) May not be ideal for locations with REALLY hard clay soils or underlying layers of rock.
4) Extra precautions may be needed in locations where various animals can wreak havoc (moles, rats etc)
5) Certain (non-native) earthworm species may not be appropriate for use in some locations – especially those worms adapted for at least a partial soil habitat.
6) Can sink substantially if you don’t continue to add wastes periodically (better suited as a “continuous” system than a “batch” system).
In case you’re wondering why I don’t really write about my vermicomposting trenches anymore – it’s because they’ve basically filled in permanently and turned into vermicomposting windrows! haha
I am still using them in the exact same manner as before during the growing season (i.e. continuing to add rich organic wastes, and planting crops nearby) – and I’ve continued to be impressed with the results!
To learn more about my adventures with vermicomposting trenches, be sure to check out the list of blog posts I’ve linked to on the “HOT TOPICS” page!
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Two posts in a day–Bentley, you’re spoiling us!
Have you ever considered moving your trenches? I’m just starting year 2 of my trenches and am thinking about (gently) digging the castings into the surrounding bed and moving the trench to another area. Thoughts?
What about using a “1 bottom” plow to go along next to the existing trench each year. The furrow will be in easy travel distance for the works and the dug up soil will simply go on top of the old trench and fill it in as it continues to sink. If you don’t have a plow then I guess hang digging is an option.
Not sure I follow you, Matt. Is the furrow where you would be planting each season? Forgive my ignorance – suburban “farming” is a lot different than the real deal! lol
The furrow(trench) would be directly next to the filled compost trench from the previous year. As the plow opens up this years new trench it will roll the dirt over on top of last years filled in trench. This will give you a fresh place to dump organic matter and prepare the older trench for this years planting. Obviously this would have been done several months ago in the spring before planting, or maybe the fall???
I haven’t done this yet, I’m still just digging pits all over the place, but after reading this article I think this trenching system will be my new method. The seeds/transplants will be planted in the “real dirt” that is now on top of the old trench, and as the roots grow down a few inches they’ll get into the “good stuff” from last years composting.
I’m not too good with explaining myself in text I guess.
We’ll have to make a video for next year! 🙂
Ahh ok – gotcha!
I like the idea of trench rotation, but not sure I would want to be heaping soil over top of my composting worm habitat – I suppose it wouldn’t be too difficult for most of them to push through the dirt to get over to the material in the new trench, but perhaps the key would be to dig a lot of that wormy material out prior to filling in and planting over it.
Anyway – interesting idea. Do let me know how you make out with it!
Hi Bentley, we currently have a bin worm compost that I would like to make it outdoor, preferably in-ground during the winter and going forward. As I was researching into how I may go about doing this, I came across your vermicomposting trench and am very excited! I just have a few questions. During the winter, will the worms freeze and die? Would it be too cold for them when it snows? If so, how would I go about keeping them warm and alive? I live in Colorado… Thank you so much for your advice!
Not sure what sort of temps you see in the winter, but here in Ontario (Canada) it certainly gets well below the freezing mark with plenty of snow, and I have no problem keeping the worms alive over the winter. I actually keep a stretch of bed essentially active all winter long (you need to really heap up the materials and add lots of insulation like straw, fall leaves etc.
If you just want to keep them alive – putting a thick layer of fall leaves, straw etc right over top of the trench should be enough (but again I’m not all that familiar with your neck of the woods – it may not be feasible is some really extreme climates)
Thank you for your answer! Sounds like the worms will survive in the ground in the winter afterall. I will give the trench composting a shot this year. I was just getting tired of bringing the worms back in the house and the musty smell that comes with it… One more question about keeping the trench active all winter – how do you keep putting waste in the trench when you have insulation on top? Do you push the insulation aside, dump the food waste in the trench, then cover them back with the straw, leaves etc? Thank you so much for your advice!
I keep a tarp over top of the leaves/straw etc so that I can easily uncover the bed once it starts getting covered in snow (tarp is great extra layer of protection against cold winter winds as well). Once “inside”, I just push back insulation materials and add food materials down below (then cover back up).
Hi Bentley, sorry to bother you with more questions… I have been reading some about compost being used as a soil remediation method. I have been wanting to plant my garden in the ground for a while, but we weren’t sure about the soil conditions i.e. whether somebody before us dumped a bunch of chemicals in the soil etc. We definitely don’t want to eat contaminated zucchinis and tomatoes! So, I was wondering if this composting trench idea will help remediate the soil? Also, I would like to know your thoughts on composting as a soil remediation method. Thank you once again!
After you fill up your trench I see the grass has grown back in. Do you have to add it to as it empties/ sinks? Or is this a one time thing?
I don’t allow grass to grow into the trenches, but the vegetation in the garden certainly extends over them. My recommendation is to continue adding to your trenches since they will indeed sink otherwise – plus, this way you end up with more nutrients for your plants (and food for your worms).
I had a small backhoe dig up tree stumps on my new property and also had them dig a 30×30″ trench along the border (this was a fast way to get rid of tree roots in my future deer barrier hedge will be). It has been sitting empty while I have been working on other projects.
Now I am thinking that this will be a great way to try out your trench vermicomposting method. My soil is very poor, dry and compacted. I have a lot of weed material that I will chop with my mower and I plan to buy a lot of straw. Will this work?
My second question is should I try a mix of redworms and nightcrawlers in order to compost AND loosen the lower levels of my soil? I am not planning to separate worms later, just move them on to new trenches or windrows to prepare more soil for planting. I am not concerned about the level dropping in the original trench, I will just add more fill dirt and compost before planting.
My third question is how many worms would you advise for a 10 ft by 30″ trench?
Thanks, you provide quite a useful service & some humor to your readers!
Very interesting article on how you got started with outdoor composting! A lot of work and great results! Your garden looks beautiful. My worms have been rocking and rolling downstairs and instead of one bin I now have 4. I got tired of taking care of all these bins so I have just made a small hole in the garden and dumped a lot of them in there. I covered it with horse manure and not finished compost. I hope it grows vegetables as beautiful as yours! I still have one bin in the house.
Before I dug the hole I put one bin outside to experiment. The literature says that worms don’t live over around 85 degrees. I put my bin in a spot that was in the shade all day long. Two days were 104 degrees. We had a heat spell. The worms did fine. So I am not sure how to understand that they don’t live beyond 85 degrees???? I mean they are manure worms from outside so I would think they can handle hot temperatures. I would think that they just burrow deeper. Can these worms actually burrow in soil?
Thanks for a great website!
What literature are you referring to? I’ve read that Red Worms can tolerate higher temps than 85 – more like 95. Not 104, I’ll admit – but then again, I don’t necessarily always trust the findings from the academic literature. Red Worms always manage to surprise me in terms of what they can tolerate. Assuming you are talking about a enclosed (bottom & top) plastic “bin”, I am definitely impressed that the worms were OK sitting out in 104 degree heat. If it’s the pit we’re talking about, or a bin with no bottom that wouldn’t surprise me nearly as much. As for “burrowing” – composting worms are not really great at digging into normal soil, but if it’s rich in organic matter they could certainly move down.
Thanks for your awesome! site:-)
It doesn´t sound like you have any problems with rats in your trench. Is that because rats aren´t attracted by the sort of waste you use, or is there another reason?
I really want to give this method a try come spring, but I am a little worried that it might attract unwanted attention from rats – we have quite a few of them around.
I dug a 2½ feet deep hole by 3 feet wide hole with a
c-shape berm around it this past year.
originally it was suppose to be a pond but I never got
around to lining it which was great because my yard
would of flooded that spring if I had.
So I made tomato circle based of the banana circles of S.America
with a center compost pit this past summer.
This fall its filled with thousans of worms. 🙂
I was reading the comments on vermaculture trench method
and Andreas Haunch expressed her concern about rats.
I have found putting the kitchen scraps through a bokashi bin
works wonders for detiring rodents/rats.
Bokashi uses microbes to pickle the food scraps producing
an apple cider like smell which the rodents dislike but the worms
happen to enjoy it because it helps to break the food down
and provides microbes for them to eat. It is easy to make with
kifer yogert or rice water and molassas.
After reading through the site, I thought you all would provide excellent insight to help me out. I have been vermicomposting in my basement over the last six months, and thought with the Spring and frost no longer being an issue, to move the worms outside. I realize in hindsight that the compost I already created outside in the fall may not have needed worms, but at the time, I added the worms because I was afraid they were dying in the indoor bin due to overcrowding.
I was hoping that you could give me some pointers as to what kind of ratio, moisture and environment I can create in the outdoor compost heap (measures 3X 4 and is 1.5 ft tall) It has wooden stakes for structural support around three sides. The temperature is 63 degrees Farenheit, also the worms are beneath the first 3 inches or so and have reduced in number. I would also like to know what I could add as well as kitchen scraps (vegan mostly), and how to properly aerate the compost so the worms are healthy.
Thank you for any advice or resources you would be willing to provide.
After being inspired by your article I decided give this a try in my greenhouse last year. I have a raised bed framed in cedar on the inside and cinder block outside that is two feet tall and 2 1/2 feet wide by about 24 feet long. I dug a trench 8 inches wide and two feet deep along the cedar wall and filled it with horse manure cardboard strips and compost from my worm bin. It made a dozen tomato plants and a couple dozen basil plants very happy. I added material as it sunk and the worms loved it.
This spring I dug the trench out and ran it thru my casting harvest tumbler and topped up the rest of the bed with about two inchs of castings. I harvested an additional 5 40 recycled dog food bags full of castings. The spring spinach leaves are the size of my hand. By the way I only got two buckets of ruff compost out of the trench everything else went thru a 1/8 inch screen in the tumbler.
When you mentioned you had to desist with your supplies of waste, it seemed to me that perhaps that was because of the slower activity in composting the food. Perhaps you could have used a faster and more effective method…the black soldier fly. I am sure it is in the USA as well. It also gets rid of meat, fats and produces larvae for chickens to eat and for fish. Much faster than a worm. But I use a combination of both….together, in what we call a COMPOT. Worms stay outside the dug-in COMPOT and come in to eat and go out to “sleep”. Improves soils around a metre around the pot.
I am from Australia and an therefore unaware of whether the fly would survive in your winter time. It won’t here in Canberra but it’s eating rate is considerably faster than the worm.
Very effective indeed
I use a heating element in the ground, just 150 watts and can maintain a temperature of 29 degrees celsius and that keeps things alive and growing for those 2-3 months that are impacted by frosts and temperatures of up to -7. Celsius again.
Just a thought.
I dug up some of my trench today.
1- The bottom was smelly almost sewer-ish. ( It unfortunately gets waterlogged. I guess this is the issue?)
2- The worms are about 3x as big as the indoor ones. Same family.