There are many good reasons to compost (see: diverting organic waste from landfills, turning your kitchen scraps into nutrient-rich plant superfood, a friendly relationship with earthworms), but one of the best things about it is also one of the most baffling: the slowness of it. 

Composting at home, either with a backyard pile or indoor vermicomposting bin, means adjusting to nature’s rhythms at the microbial level. And when you’re stoked about turning all your peels and stems and past-their-prime leftovers into usable compost, those rhythms feel…slow. 

Waiting anywhere from two to four months for usable compost is normal, but anything slower than that (especially in conjunction with abnormal smells) might be an indication of an imbalance, or signal a need for a change of technique. Read on for a few ways to optimize the processes unfolding under all those food scraps and yard trimmings — and how to know whether things are moving at the right pace or need a little nudge.

10 Ways to Speed Up Compost 

On its face, compost is simple: given time, and with the help of insects and microorganisms, organic waste decomposes into a nutrient-dense material that can be used as a soil amendment. In reality, finished compost, affectionately dubbed “black gold” by gardeners, is the result of steady attention to the heat of the pile,the mineral make-up of its components, and the balance of both regular circulation and stillness.

Understanding, and planning for, those conditions makes the process go smoother — and, ultimately, faster. 

1. Make a bottom layer of twigs

If you’re starting a new pile, consider adding a layer of twigs and small branches at the base: this will create a steady-state of air flow from the bottom, aerating the pile in between turns. This may make collecting your finished compost slightly difficult, but it can be a useful tactic in wetter seasons, when excess moisture can oversaturate your pile and prevent adequate circulation.  

2. Make a larger pile

You might think that a smaller amount of organic material would take less time to decompose, but a too-small pile can actually slow the process down, since it may not generate enough heat.  

Your pile should be big enough to achieve the necessary temperatures, but small enough that you can easily turn it. A three-to-five foot square is ideal for loose piles; most commercial plastic composting bins are around this size, or a little smaller, with lids and closed sides that can make it easier to trap heat. 

3. Turn compost frequently

Turning your compost is all about introducing oxygen to your pile. Oxygen is what sets a compost pile apart from a landfill: without it, organic materials decompose and release higher levels of gasses like methane and carbon dioxide (a process known as anaerobic decomposition), bringing on unpleasant smells. Aerating the pile at regular intervals is key to the survival of the microbes and bacteria doing the hard work of turning waste into finished compost, which generates the heat necessary to break materials down. 

4. Break up scraps into smaller pieces

In most cases, the organic material you’d add to an outdoor compost pile will come in a variety of sizes and textures, some of which will break down faster than others. (A banana peel will always beat a cabbage core, for example.) If speed is your goal, chopping, grinding, or otherwise shredding your material down to ½ - 1” pieces will do the trick. 

Using a Mill food recycler to pre-process kitchen scraps into uniformly-sized food grounds is an incredibly efficient way to introduce large amounts of nitrogen-rich material to your pile. Plus, it makes it possible to compost meat and to compost dairy items (think bones and cheeses) without generating rancid smells or attracting pests — all in a format that makes it easy for microorganisms to digest.   

6. Keep the right moisture level

Moisture helps bacterial populations thrive in a compost pile and regulates temperature — both in generating warmth and preventing the pile from overheating in hotter weather. This is why keeping things adequately damp is a big part of the process. When you first construct your pile, wet things down with a hose until the mixture has the consistency of a wrung-out sponge. Once your food scraps begin to break down, monitor the moisture levels, adding more water as needed to maintain the same damp, crumbly consistency. 

7. Insulate your pile

Heat, in a composting pile, is generated by the breathing of the microorganisms processing the organic material, but it is also what allows them to survive in the first place. Temperatures should be between 90°F and 160°F for best results. If you’re composting items like meat or dairy, your pile should consistently run at about 135°F.

In colder months, you can expect heat loss to slow things down; counteract it by covering outdoor compost piles with hay, or a large tarp, to trap heat and moisture. If you’re composting indoors (in say, a chilly garage), you can wrap vermicomposting bins or trays in a few layers of bubble wrap or moving blankets. 

8. Add old compost

Some composting experts like to treat an outdoor pile a bit like a sourdough starter, where a portion of a finished batch can help to supercharge a fresh one with beneficial bacteria and fungal threads. While there’s no need to add anything to a pile of organic waste, many gardeners find inoculating it with highly active microorganisms in nutrient-rich material can give things a boost.  

9. Use the Berkeley method

If you have a little extra time and attention in your quest to speed up the composting process, consider the Berkeley method, developed by University of California, Berkeley professor Robert D. Raabe. The technique hinges on creating sauna-style conditions for the heat-loving bacteria in your pile, coupled with intense daily “inside-out” turnings.  

To start, assemble your organic materials in a 3’ x 3’ x 3’ bin or pile, aiming for a 30:1 ratio of carbon to nitrogen, or 3:1 brown material to green material. The best way to eyeball this is to mix equal volumes of “greens,” like fruit and vegetable scraps, grass clippings, and uneaten food, with dry “browns” like fallen leaves, straw, and small bits of mulch or pruning trim (alternatively, Raabe suggests cut-up and shredded bits of cardboard, cartons, and paper bags will also work). Wet everything down until it’s about 50 percent moisture — a little water should drip off when squeezed. 

Because this method works at the uppermost limit of ideal composting temperatures, you’ll need to keep things from getting too hot and killing off the important bacteria. The best way to regulate this is with airflow, so give your pile a few extra turns to let off heat if you see temperatures above 160° F. Let the pile sit for the first day or two, then turn daily, with the goal of moving the material on the outside of the pile to the center. If you like, using two bins for transference can make this easier. Cover with a tarp or a tight fitting lid after each turn. Ideally, this process creates finished compost within two weeks, provided you do not add anything to the pile once you begin. 

10. Add worms

Composting with worms, or vermicomposting, is one of the quickest ways to transform your kitchen scraps and yard trimmings into a usable fertilizer in a cooler climate. You can add worms directly to your outdoor pile to move things along (anywhere from a few hundred to a thousand, depending on the size of your bin and how much food you’re adding on a regular basis to help sustain the population), or you can keep dedicated bins for them. 

Worm bins can be kept indoors; they don’t produce odors or pests and don’t require much space. Vermicompost, or worm castings, can be applied directly to your garden soil, or used to make worm tea, a water-based soil amendment. Red worms are the most common worm for composting thanks to their quick reproductive cycles, amenable palates, and adaptability to environmental conditions; you can find them online by the pound.

Reduce food waste with Mill

You don’t have to be looking to break world records on compost turnaround time to reap the benefits of Mill: by breaking your kitchen scraps down into odorless, dry, food grounds, Mill gives you multiple ways to put your organic waste to good use, whether in a backyard pile, worm bin, or community garden. 

Sources:

1. Compost Magazine: “17 Easy Ways to Speed Up Your Compost.” https://www.compostmagazine.com/how-speed-up-compost/

2. Division of Agricultural Sciences, University of California: “The Rapid Composting Method.” September, 1981. https://ucanr.edu/sites/solanomg/files/245165.pdf

3. Uncle Jim’s Worm Farm: “How Many Worms Do I Need for My Composting Bin?” October 10, 2023. https://unclejimswormfarm.com/how-many-worms-do-i-need-for-my-composting-bin/