Composting Tips for Kitchen Waste and Cardboard

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Composting tips for kitchen waste and cardboard

One of the benefits of staying home for Covid control is more time for gardening, and perhaps more time for composting, too. Cooking at home more often produces greater quantities of compostable food waste, and in many areas suspended recycling services have led to unsightly stockpiles of cardboard that can be dealt with in part via composting. There also are many new gardeners among us who want to start composting, which can be confusing at first. Here’s a roundup of composting tips of special relevance during the Covid crisis.

With trench composting, kitchen waste is buried in marked garden beds

Trench Composting Kitchen Waste

Isn’t it amazing how fast your countertop compost pail fills up these days? Between continuous home cooking and garden veggies that need trimming and cleaning, your kitchen waste stream will soon turn into a gusher.

Here you have many choices, including the age-old method of simply burying kitchen waste in the garden, called trench composting. Fruit and vegetable trimmings, coffee grounds, used paper napkins and icky meatless things from the back of the fridge can go straight into the ground provided they are covered by four inches (10cm) of soil. When trench composting kitchen waste, most gardeners work their way down a row or bed, marking the last buried cache with a stake. The drawback to trench composting is that you must risk muddy shoes every time you need to dump your compost pail, so you also might want to keep a stationary composter in an accessible spot.

Earthworms and other tunneling creatures improve the soil under and around a stationary composter

Stationary Composters Improve Soil

Stationary compost containers that sit on the ground hide kitchen and garden waste from view, retain moisture and warmth to promote decomposition, and attract earthworms, tunneling insects and assorted mini-mollusks to the composter’s footprint. If you are expanding your garden, locate a stationary composter where you plan break new ground to make use of its passive soil improvement properties.

You can buy inexpensive stationary composters made from recycled plastic, or make your own by removing the bottom from an old trash can. Or, take up box composting by using a big cardboard box as a single-season stationary composter. As you fill the box, put slow-rotting rough stuff around the edges, with kitchen waste and pulled weeds toward the center. When the box is full, start another one. Box composting also smothers weeds and grasses, so it’s a good method to try in places you plan to bring into cultivation.

You can compost kitchen waste indoors with the help of composting worms

Composting with Worms

The quietest, most odor-free pets I ever had were earthworms that lived in a plastic storage bin in my basement. They loved tattered lettuce leaves and leftover rice and pasta, which they turned into rich vermicompost for my garden. I kept worms as an enjoyable hobby, but if the only place you have to compost is your storage room, try composting with worms. A plastic bin with its sides well perforated with air holes makes a good container, and you can use shredded cardboard or newspapers for bedding.

Earthworms captured outdoors will do an adequate job of turning kitchen waste into compost, but it’s best to get some composting worms, also known as red wigglers (Eisenia foetida). These guys thrive at cool room temperatures and multiply rapidly when conditions are good. When you want to harvest vermicompost, open the bin and place a pile of worm-laden material on the inside of the lid. Wait ten minutes or so, and the worms will move the middle of the pile where they can be gathered and returned to the bin.

Cardboard boxes are easiest to flatten when wet. They then can be composted or used as mulch in ornamental beds

Composting Colored Cardboard

In 2017 I wrote about the ways I deploy cardboard in the vegetable garden, mostly by using clean, undyed cardboard shipping boxes to smother weeds between widely spaced plants. But now it’s Covid time, my local recycling program has been suspended, and I’m stuck with either composting my cereal and dog biscuit boxes or trashing them.

Two composting methods are useful for what I think of as nuisance cardboard. You can use the flattened boxes as a sheet mulch in flowerbeds, which is then covered with enough wood chips or other mulch to hide the cardboard from view. Or, simply layer the wet cardboard into an outdoor heap of coarse material, keep it as moist as you can, and let time do its thing. Either way, save yourself work and aggravation by thoroughly dampening the boxes as you prep them for compost duty, or simply leave them out in the rain. Water melts glue and lifts tape like magic.

Is Covid composting a thing at your house? How does sheltering-in-place translate into composting-in-place for you? Please share your story below.

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Show Comments


"Good idea on composting cardboard. How long does it take to breakdown if the cardboard is put in a pile? Is there a limit on the height of the pile? With all the online shopping the boxes really pile up. "
Mark Hausammann on Sunday 24 May 2020
"Mark, moisture is the biggest variable. This week I put torn wet cardboard into my stationary composter, and used more as an undermulch in a pathway. With warmth and even moisture, there will not be a trace of them after six weeks or so."
Barbara Pleasant on Monday 25 May 2020
"You've given me lots to think about ways to compost and what to compost. Thankfully, we still have recycling but I think I'll use the plain cardboard boxes in my compost bin. Not quite ready to use colored cardboard for my edible crop compost. Stationary composters--trash cans and boxes are intriguing. For urban and suburban gardeners opossums, raccoons and rats could be a problem for trench composting. Having sufficient garden space for these endeavors can be challenging for urban gardeners. As always thank you for your sound garden advice."
ediblegardens52/Sue Martin on Tuesday 26 May 2020
"Sue, you are right to be concerned about vermin in compost. Raised tumbler composters work best where animals are a problem."
Barbara Pleasant on Thursday 28 May 2020
"A video on YouTube brought me here. I am new to gardening and enjoying all the new knowledge in the hobby. We have been composting and our soil is looking good. Since using cardboard our recycling is low and our soil is earthy. "
Marcyl on Thursday 28 May 2020
"I started using cardboard as a weed control. Then I noticed that there will moles coming into my yard. I believe they were trying to get to the grubs under the cardboard. I began to put down used cat litter before placing the cardboard. That seemed to work pretty good. I did not want to use things such as GrubEx or other chemicals. I think it's important to let people know that yes there will be vermin coming into the yard if you're using some of the methods mentioned in your article. Many people take the appearance of their grass pretty serious in my area. Mole tunnels would not go over well. Also, my neighbors on either side seemed very nervous about my kitchen scraps bringing added vermin into our yards which are connected, urban sized lots. We have possums and raccoons getting in our large trash bins even without composting kitchen scraps in the yard. The larger, plastic composting bins can be quite expensive. For now, I'm using a plastic tub with holes drilled in it. It's ok, but sometimes the raccoons remove the top and make a mess of my best laid composting plans/efforts."
Toni Johnson on Saturday 30 May 2020
"Have you any information if dyed cardboard causes negative effects by leaching into the soil? We have been gardening for years, and I've procrastinated setting up a compost because I didn't know exactly how to do it. I was tired of waiting this week, so a few days ago I set up something temporary outside in a shallow 75 gallon horse trough I had laying around. It's got some soil, sod, garden refuse, and kitchen scraps (non-meat of course)."
Nicole F on Friday 12 June 2020
"Nicole, the safest cardboard is plain, brown with little ink or glue, so that's what I use in or between edible beds. I use colored cardboard in the flowerbeds, and sometimes to lighten up compost that's too wet. Good luck with your horse trough compost! "
Barbara Pleasant on Monday 15 June 2020

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