Should you cut up compost scraps? Shredding scraps for composting is a common practice, but you may have wondered if this practice is necessary or even effective. To find the answer, let’s look at the biology of compost.
Composting Fruit and Vegetable Waste
You add plant material, such as food scraps, garden waste, and lawn clippings, to the compost pile. Small invertebrate animals like earthworms, millipedes, sow bugs, and beetle grubs feed on the plant material, breaking it down into smaller pieces and increasing its surface area.
The greater surface area allows microbes, including bacteria and fungi, to access more of the organic material in the scraps and eventually break them down into finished compost. Meanwhile, predatory invertebrates like centipedes and spiders feed on the first group of invertebrates and contribute to the rich biology of the compost.
But will composting fruit and vegetable waste into smaller portions beforehand make any difference to this naturally occurring process?
Does Cutting Scraps Help Compost?
The answer to this question is yes, but it’s not required. Cutting up scraps will help your compost break down faster by increasing the surface area of the compostable material. It will also help break up resistant materials like peels and shells. This allows microbes to access the decompostable material in the scraps and get to work faster.
However, even if you don’t shred scraps, the worms, millipedes, snails, and other plant material-feeding invertebrates in your compost pile will shred them for you by consuming them and breaking them down into smaller pieces. The pile will compost with time anyway.
On the other hand, it is important to break up large, hard-to-compost materials like sticks and wood mulch into smaller pieces to help them break down faster. Wood can take years to break down on its own, making it unlikely that large pieces will compost and be ready to use at the same time as the rest of the compost pile.
When composting fruit and vegetable waste, shredding or grinding is less important, and it’s certainly not essential. But it can help your compost pile break down faster, providing you with finished compost that will be ready to use on your garden sooner. It can also lead to a finer-textured finished product that may be easier to incorporate into your garden.
If you do cut up scraps before adding them to the compost pile, be sure to turn the pile often. A compost pile consisting of smaller pieces will be more compact, so there will be less air flow within the pile, and it will benefit from the extra aeration when you turn it over.
Does Kitchen Waste Belong in a Compost Pile?
Q. I recently heard you advise a listener to not bother putting kitchen scraps in her compost pile because they add little to the finished compost and slow the process down. But our earth and our gardens need us to compost more of our waste—as much as possible. How about multiple compost piles—one for a quicker, more finished compost, and another just for compostable kitchen scraps? Landfills aren't good for our gardens, and the earth itself is a gigantic garden.
- ---Cynthia in Smyrna, TN (a suburb of Nashville)
I built a compost pile for my shredded fall leaves and kitchen waste last autumn, and have continued to add our kitchen waste to the compost bin since then. Is that OK? If not, what would you recommend I do with all the veggie scraps and coffee grounds I continue to accumulate throughout the year?
I've been using one of those big black recycled plastic composters for three years now, and am generally happy with it. I 'slow compost', adding kitchen greens, shredded leaves and coffee grounds through the year. When the composter is full, I remove the material, allow it to continue composting in a pile and start another batch in the composter. But this summer there are hundreds of grey-white segmented larvae happily wiggling around in the composter. Any idea what they are? Should I worry? And should I follow my regular plan of moving this batch into a pile and starting a new batch in the composter?
- ---Claudia in Mount Holly, NJ
A. I told Claudia that her new pets could be the larvae of almost any fly—most likely the predatory robber fly or pestiferous house fly—and that, yes, she should dump it all into an open pile and let Nature take it from there.
Now, I tend to associate such creepy crawly visitors with a compost pile that's way too heavy on the kitchen scraps, and asked about her mix of materials. "I am overwhelming the composter with green waste," she replied after reading a few of our previous articles on the subject. But what can I do? I don't want to put our kitchen waste into a landfill!"
Of course, I agree 100% with Claudia and Cynthia we should not be sending kitchen waste (with the exception of meat, fat, bones and other non-vegetative material) to the landfill. But as I have explained (more like 'pleaded') many times in the past, we shouldn't be filling composters with lots of garbage either. Two big reasons: With the exception of coffee grounds—which are very nutrient-rich and help make super-excellent compost—our kitchen waste adds almost no actual nutrition to the finished compost. And, more importantly, composters that are overwhelmed with kitchen waste don't compost—they just sit there, stinking up the joint and attracting flies, rats and other vermin.
When Sir Albert Howard and J. I. Rodale first began to popularize composting in the early 1940's, they stressed that the act was an "imitation of Nature". In Nature, deciduous trees and shrubs drop their leaves to the ground, where wind, weather, animals and insects shred them up. Small amounts of animal and bird manure are naturally added to the mix, along with the spent remains of green plants and other forest litter. Nature does NOT pile up big stinking heaps of apple cores, lettuce leaves, broccoli stalks, pizza crusts and tea bags.
Now, this doesn't mean that you can't or shouldn't divert your kitchen waste. You can and you should. But you need to be thoughtful about how you do it.
One way—perhaps the best way—is with specialized worms redworms to be precise. In the right kind of bin, redworms + bedding (shredded black and white newspaper, shredded fall leaves or other 'brown', carbon-rich material) can turn ordinary kitchen waste into nutrient rich worm castings>, which look like compost but are even better for your plants. If you can't, won't or aren't able to collect and shred large amounts of leaves to mix your kitchen waste into outdoors, worms are the way to go. They're really the only rational option for apartment dwellers or others without land and a well-kept bin is a delight.
But worm bins should not be free handed. You are welcome to make your own bin, but learn the needs of the worms—things like aeration and drainage—first. (The emails I've received from people who didn't research bin-making in advance are too lurid to read on the air.) In addition, worm bins are generally for indoor use only they can't be left outside in areas with freezing winters or placed in direct sun.
Now I really like our listeners to succeed on the first try. So if this sounds like your kind of solution, buy your first bin, buy a batch of starter worms (or get some from a friend who's already doing it they'll have plenty to spare), and begin your adventures in vermiculture on sure footing. (Heck, try a bin even if you DO have lots of outside room and shredded leaves! I'm going to set up my first bin this month, so that I don't have to trudge through snow to recycle our kitchen waste in the dead of winter anymore.)
Otherwise (or in addition), get ready for Nature's greatest gift to gardeners and shred all the fall leaves that are beginning to come our way. Shredded leaves become compost much faster than whole leaves, and shredding reduces their volume dramatically—by at least a factor of 10, allowing you to bag up a big enough supply to process the next year's kitchen waste by composting via the batch method outdoors.
It's easy—just fill a bin with mostly shredded leaves, mixing some kitchen waste in as you go. (Don't 'layer' the different ingredients—mix them all up. Whoever starting telling people to layer their compost ingredients failed Physics 101.) When that container or pile is full, start a new batch with your saved leaves and most recent kitchen waste.
Repeat this wonderful process all fall, winter and Spring because nobody ever got to September wishing they had made less compost!
The composting process
The composting process involves four main components: organic matter, moisture, oxygen, and bacteria.
Organic matter includes plant materials and some animal manures. Organic materials used for compost should include a mixture of brown organic material (dead leaves, twigs, manure) and green organic material (lawn clippings, fruit rinds, etc.). Brown materials supply carbon, while green materials supply nitrogen. The best ratio is 1 part green to 1 part brown material. Shredding, chopping or mowing these materials into smaller pieces will help speed the composting process by increasing the surface area.
For piles that have mostly brown material (dead leaves), try adding a handful of commercial 10-10-10 fertilizer to supply nitrogen and speed the compost process.
Moisture is important to support the composting process. Compost should be comparable to the wetness of a wrung-out sponge.
If the pile is too dry, materials will decompose very slowly. Add water during dry periods or when adding large amounts of brown organic material.
If the pile is too wet, turn the pile and mix the materials. Another option is to add dry, brown organic materials.
Oxygen is needed to support the breakdown of plant material by bacteria. To supply oxygen, you will need to turn the compost pile so that materials at the edges are brought to the center of the pile. Turning the pile is important for complete composting and for controlling odor.
Wait at least two weeks before turning the pile, to allow the center of the pile to "heat up" and decompose. Once the pile has cooled in the center, decomposition of the materials has taken place. Frequent turning will help speed the composting process.
Bacteria and other microorganisms are the real workers in the compost process. By supplying organic materials, water, and oxygen, the already present bacteria will break down the plant material into useful compost for the garden. As the bacteria decompose the materials, they release heat, which is concentrated in the center of the pile.
You may also add layers of soil or finished compost to supply more bacteria and speed the composting process. Commercial starters are available but should not be necessary for compost piles that have a proper carbon to nitrogen ratio (1 part green organic material to 1 part brown organic material).
In addition to bacteria, larger organisms including insects and earthworms are active composters. These organisms break down large materials in the compost pile.
How To Make Incredible Compost From Leaves
Select The Best Leaves For Composting
When it comes to making great compost from leaves, it all starts with selecting the best varieties for composting.
Maple leaves are among the best of the best when it comes to composting. They break down quickly, and are high in nutrients.
At the top of the list are the leaves of maple, birch, ash, cherry, cottonwood and fruit trees. All of these are excellent choices to create a pile from. Not only are they higher in nutrients, the leaf structure of these varieties break down fast.
What about oak trees? Well, they can be used in moderation, but since they lean toward the acidic side, they can throw a pile’s PH levels off. In addition, oak leaves are among the lowest in nitrogen and other nutrients.
It doesn’t mean you can’t use oak leaves in your pile, but keep it to less than 20% of the make-up to avoid issues.
There are a few trees to avoid all together. Most notably walnut, eucalyptus and horse chestnut trees. The leaves from walnut and eucalyptus contain toxins that can harm plants, and prevent some seed crops from germinating.
As for the horse chestnut and it’s close relative the Buckeye tree, they can produce a toxin that can be harmful to humans if in high enough doses. Although the toxin is concentrated in the nuts of these trees, it can be hard to separate out when collecting. It’s simply best to leave them out of the pile to be safe.
Shredding The Leaves
So now that you know what leaves to use, it’s all about building a leaf-filled compost pile that will decompose fast.
And to do that, it all starts with shredding! Simply put, whole leaves will take forever to break down. By shredding them before creating your pile, you will speed up decomposition 10 to 20 times faster.
Shredding your leaves before you create your pile is a must for making quick compost. The broken and torn edges created from shredding help to decompose the leaves quickly.
There are an incredible amount of lower-cost electric leaf and debris shredders on the market these days. And many of them really do a pretty good job at shredding. See : Electric Leaf Shredders
However, a push mower or riding mower can accomplish the task with ease as well. We use our push mower and bag attachment to shred huge piles of leaves quickly every fall. It’s easy to do, and makes quick work of the task.There are many electric leaf shredders on the market like this one from Worx that do a good job of shredding leaves. You can also use a lawn mower or push mower as a great option for shredding.
Building The Pile
Now comes the building of a fast working leaf compost pile. Unlike a typical compost pile that you create and continue adding to as materials become available, a leaf pile can be made up all at once.
That way, it can get working and stay working, and not have to break down additional “new materials” later.
Even a pile of shredded leaves can take awhile to compost without a little help.
But a pile made from leaves only will still take a long time to decompose. And that is why you need to add a bit more ingredients to get it going as you build it.
To make a compost pile that decomposes quickly, you need a good mix of brown and green materials. In this case, the leaves are a lot of brown. So adding in some green will get it going right away. (See: The Greens & Browns Of Composting)
Getting The Right Mix
It just so happens that green grass clippings are great green materials. As is manure (chickens, rabbit, horse, cow), coffee grounds and food scraps too. All of these heat up a pile, and also break down quickly – making them perfect additions.
Coffee grounds are a great addition to a leaf compost pile. They add nitrogen and other trace elements, and are already broken down into a soil-like form.
But there is one more key ingredient to add as well that can really speed things up – and that is fresh compost. By adding compost from an existing pile, you instantly introduce all of the beneficial microbes and organisms that are key to breaking down materials.
It’s important to remember that with a leaf pile, it will eventually decompose no matter what you have available to add. But the more greens you can add in to balance the browns, the faster it will work.
What Should Go Into Your Leaf Pile
As an example, here is what we use in our fall leaf compost piles to get the working fast:
We start our leaf compost piles with about a 3′ x 3′ x 3′ pile of shredded leaves. Next, we add in a few 5 gallon buckets of fresh compost, and a two or three more buckets of fresh green grass clippings.
A pile of leave compost with compost, chicken manure/straw , and old potting soil mixed in.
Since it is the end of the growing season, we also sometimes throw in the soil/plant mix from a few of our hanging basket and container plants.
We finish by adding in a few 5 gallon buckets of our chicken manure / straw mix from our coop, and any vegetable scraps, coffee grounds, etc. we might have on hand.
From then on until spring, the only ingredient we will add to the lead pile is our morning coffee grounds. They continue to add a source of green to the pile, and since they are already soil-like – we don’t need to wait for them to break down.
Turning The Pile
Just like a traditional compost pile, a leaf pile benefits greatly from occasional turning. Not only will turning your pile a few times each week introduce oxygen, but it also helps to distribute the moisture levels in the pile.
Just as with a traditional compost pile, turning your leaf compost pile will speed decomposition.
And when it comes to creating a fast working pile, oxygen and water are absolutely vital!
Turn your pile a minimum of two times per week up until the pile freezes in cold temperatures. If it gets too dry, add a bit of water to the mix to help it along. As soon as spring temps warm, continue turning on a bi-weekly basis.
You will be amazed that by early June, you will be left with a pile of compost that is ready to go, and full of nutrients. All from a pile of leaves!
We use our leaf and traditional compost everywhere we plant, including in our containers and bucket planters.
Here is to making incredible compost from your leaves this year, and having mountains of black gold next spring! Happy Gardening – Jim and Mary
Using compost in the yard
Incorporate compost into your garden as you prepare the soil in the spring. Cover the area with 3-4 inches of soil and till it in to at least the upper 6 inches of soil. Add compost to soil in vegetable gardens, annual flower beds, and around new perennials as they are planted.
You may also use compost as mulch around flower beds, vegetable gardens, or around trees or shrubs in landscape beds. Apply a 3 inch layer. Be careful not to apply mulch close to the main stem or trunk of the plant.