Trench Composting Your Kitchen Waste

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Trench composting kitchen waste

From spring to fall, my veggie garden beds stay so busy growing good things to eat that there is little opportunity to practice the easiest form of composting gloppy kitchen waste, which is to bury it right in the garden. But by the time autumn leaves start fluttering to the ground, I have plenty of vacant space for composting in holes or trenches, which is a good thing! The trimmings from drying and canning apples and pears is more than my enclosed composter can handle, and leaving aromatic fruit in outdoor heaps is asking for trouble from raccoons, deer and other unwanted creatures. So, I bury it.

There is a method to my madness, but it is different from "trench composting", an organized plan in which parallel trenches are filled with organic waste in rotation, so that beds and pathways flip-flop back and forth as each is used as a compost trench. Trench composting would not work in my permanent terraced beds, but what does work is to identify under-achieving beds in the fall, and use them for underground composting during the winter.

Compost bucket

Like magic, I have found that fruit and kitchen waste buried about 10 inches (25 cm) deep in October disappears completely by April, when my soil is dry enough to dig. The first year I tried this, I doubted it would work, so I also fermented a big bucket of apple waste, Bokashi style, and did a side-by-side comparison of the rotting progress of fermented vs. raw fruit waste. To my surprise, the raw fruit trimmings decomposed as fast as the fermented stuff, with barely a trace of a core to be found the following spring.

Cathole Composting

When co-author Deb Martin and I were writing The Complete Compost Gardening Guide, we came up with the phrase "cathole composting" for burying and covering over caches of organic waste, just like cats do with theirs. It works amazingly well, and many people use it as a routine composting method. One friend keeps a spade in the bed being composted, and moves it down the row as holes are dug and filled with compostable kitchen waste. Another guy I know covers his holes with a concrete paver, because he uses cathole composting to dispose of fish heads and needs to make sure they are securely buried.

Whenever I am not satisfied with the performance of a bed, I can usually turn things around by peppering it with cathole compost holes filled with fall food preservation waste, and then covering it with a biodegradable mulch of chopped leaves. I use holes rather than trenches because more soil is exposed to the gazillions of microbes that turn food waste into soil organic matter. When the holes are spaced about 18 inches (45 cm) apart, the columns of soil between them become havens for decomposers from big earthworms to the tiniest bacteria. When the bed is tucked in with a thick blanket of mulch, the stage is set for slow soil-improvement miracles.

Cathole composting

More Ways to Compost Underground

Kitchen waste that comes in small pieces, for example coffee grounds or the slurry left behind by your juicer or food mill, disappears so fast when buried that many gardeners dig it into beds that are being actively used to grow plants, including the soil beneath berries and fruit trees. Chunkier materials like broccoli stalks and apple cores take longer to decompose, so it is better to bury them in resting beds, well-covered in deep holes or trenches.

Using compost holes to nourish nearby plants

Or, you can make a proper compost pit, as I often do in spring when planting peppers. I dig out a hole and layer in kitchen waste, grass clippings and pulled weeds, then cover it with mulch. I plant three or four pepper plants around the filled compost pit, which also serves as a moisture reservoir in dry weather. Some gardeners make layered compost pits in fall, and plant tomatoes or pumpkins in the enriched holes in spring.

The most inspirational story on underground compost comes from Bangladesh, where the simple technique of growing edible gourds in holes filled with bags of compost has helped many families survive after floods left their fields buried in sand. I can't help but cheer when something as simple as buried compost saves the day.

By Barbara Pleasant

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Comments

 
"Great Article! Thanks Barbara. I've seens this done with freshly squeezed orange and lemon skins. The YT gardener just covered it with a bit of lime. A small amount to offset the potential acidity. He covered them, planted into it three months later. His produce is so so amazing compared to the bed next door with the same vegetables but with the "extra" soil treat. Thanks again for this post. :)"
David Trees on Friday 27 September 2013
"Great idea but I use raised beds... Can this still be done? "
Hope on Friday 27 September 2013
"Yes, you can do it with raised beds. If you go to Barbara's blog you can see that she has raised beds. Betty Dotson"
Betty Dotson on Saturday 28 September 2013
"I wonder if you live where it freezes? It seems to me with the ground frozen, nothing would decompose when buried. Also. what about seed sprouting? I have LOTS of "volunteers" that sprout every spring, tomatoes especially. Is this a problem? I think the freezing/thawing set any dropped/buried seeds to sprouting the next spring when it thaws. I'm going to try it anyway!"
Lora on Saturday 28 September 2013
"Lora, only hot composting methods will deactivate tomato and other seeds, but there are many hazards to hanging out in the soil. In my experience, the volunteer veggies that sprout in compost are easy to pull out compared to real weeds. My soil typically freezes four inches deep in winter, but with kitchen waste below and deep mulch at the surface, it may not freeze at all."
Barbara Pleasant on Saturday 28 September 2013
"I live in Phoenix, AZ where my best garden is really in the fall/winter with great leafy greens and root vegetables. Would this technique work just as well in the summer? I usually have between July and mid September where not much but herbs are growing in my dirt garden."
Melissa Rightmire on Saturday 5 October 2013
"Melissa, in your climate your buried kitchen waste will disappear really fast in warm summer temps. Good luck! "
Barbara Pleasant on Saturday 5 October 2013
"I bury my cospost in the garden all year. In the winter when the garden is frozen, I shovel aside the snow, dump the compost pail (about 1-1/2 gal.) and cover it up with snow! It seems to freeze quickly, and I don't see animals digging it up ! and in the spring, by the time it thaws, it seems half decomposed, don't notice smell, leaving nothing for any pests to come around for. When I rotovate as close to freezing as I can, I usually don't see anything left of the compost, except for a few chunks of stuff that wasn't cut up, like apples.even then those are gone in the spring when I rotovate before planting. I believe leaving space between rows has a few advantages, * -plants grow better because they have more room, - get more sun, the bare ground dries up, making it harder for pests to get around, hence LESS PESTS! (I DO NOT USE ANY PEST CONTROL CHEMICALS!) - burying compost in the space quickly decomposes, providing food for the growing plants! I bury the compost in "catholes", in the rows between plants, and I mark the edge of the "last cathole" with a Wooden Handled Stainless Shiskabob Rod, so I know where to dig the next hole! "
Bruce on Sunday 27 October 2013
"I am a avid composter too.. but i do have a question about the Elephant Ear leaves, are they safe to put in the compost? this is my first year of having this plant"
monjardin on Friday 8 November 2013
"Like many tropical plants, elephant ears rot really fast and will disappear quickly in your compost. If you are leaving the bulbs in the ground through winter, be sure to cover them with an insulating mulch. "
Barbara Pleasant on Sunday 10 November 2013
"My question would be.... What is the rodent population where you use this method? I am afraid this would bring more problems. "
Vic on Friday 21 November 2014
"Great idea thanks. Inspired me to make my small backyard bed much better. "
ElaNe on Friday 12 June 2015
"This is a fantastic idea that I can't wait to try. Just wondering can all kitchen waste be composted eg tea bags and meat and bones etc or is it just veggie waste."
Tracy Hardy on Tuesday 8 September 2015
"A lot of people bury well-cooked bones, which is great as long as you don't have dogs ready to dig them up. Too much might attract pests animals worse than dogs, so be careful. Tea bags can go through regular compost processes."
Barbara Pleasant on Tuesday 8 September 2015
"Does anyone know where I can send our complex gardener for lessons on how to plant a vegetable garden and to create a compost heap please I live in Fourways Gardens"
Pam Zukor on Wednesday 21 September 2016
"Do you think burying compost would be ok in sandy soil (desert climate) "
Bethany on Wednesday 5 October 2016
"Good question, Bethany. Desert soils are often said to be "sterile" because they host fewer microorganisms, so they may not be as effective for in-ground composting. However, any garden soil that has been improved with organic matter so it holds moisture would probably give good results, even in the desert. "
Barbara Pleasant on Wednesday 5 October 2016
"I do a modified form of this. I store up ALLRfood waste for a full year in a 60 gallon compost digester. I also have an Earth Machine composter that holds 1 summers worth of grass clippings and shredded newspaper as they come available. In the fall after the 20x20 garden is harvested I empty and spread both bins then get the garden rototilled. Doing that helps get rid of the rotten stink and by spring time after another good tilling you can't recognize any of the compost which when spread is far from fully decomposed. The garden grows beautiful crops. When we did our yard we got the garden dug out and just regular top soil was used. To add more organic matter and to help with the smell, this year I also added 2 square bales of organic barley straw. I'm hoping that after the spring tilling it is well broken down and we have a nice garden next year. "
I on Sunday 9 October 2016
"Last fall I didn't add any straw and after the spring tilling you could not recognize any of the contents except for a few corn cobs and chicken bones that I just put back in the pit. "
I on Monday 10 October 2016
"I used to bury all plant/food waste in a garden of our summer home near Port Jervis, NY, as we had no garbage collection. Every week-end I put a load about 6" underground, moving along a small rectangular plot to a new spot each week. I found that even corn cobs were gone within 2-4 weeks, so I could cycle back to the start very soon. I now do the same in Wayne, NJ. I don't plant in the very shady area where I compost, I just use the composted soil to add to holes when I am planting elsewhere in the garden. "
Sue on Wednesday 7 June 2017
"Aggressive (very) raccoons invade my back yard and pull up any starts I plant in my raised beds (they even figure out how to get in under the hooped netting) and dig for grubs. They dig for grubs (I assume that's what they're eating) even under mulch spread over thick cardboard in the paths between the raised beds. They are hostile, and even water sprayed on them only deters them for a few minutes, then they come back. Suggestions? I left the garden fallow rather than deal with their mean spirits and aggression this summer. "
Pamela Crawford on Wednesday 20 September 2017
"I also have a hostile neighbor whose house is about 10 feet from mine, the other side of a fence. She planted a cottonwood tree that's grown about 5 or 6 feet a year and now is the height of a 5 story building, completely shading my garden that I used to be able to grow from corner to corner. The cottonwood shoots are coming up in my garden with arm-wide roots that need to be dug up and thrown over the fence. It's an inappropriate tree for our small backyards (once Italian kitchen gardens when these bungalows were built about 100 years ago) and drops limbs, leaves and litter in Spring and Fall with the wind. She's unwilling to do anything about it. Or the giant bamboo she planted next to the fence. Suggestions?"
Pamela Crawford on Wednesday 20 September 2017
"Oh, Pamela, which is worse? Mean raccoons or an inconsiderate neighbor? In most places you can remove tree limbs and other vegetation on your side of the property line, which does not really solve the problem. Can you get help from local animal control people with the raccoons? A loud, attentive dog might solve both problems. Good luck. "
Barbara Pleasant on Wednesday 20 September 2017
"informative. thanks a lot"
ayy on Monday 23 October 2017

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