How to Speed Up Composting (Or Making Friends with Microorganisms)

How to speed up composting - use bacteria
Courtesy of the CDC

Asking the question “how to speed up composting” is like asking, in a less direct way, how do I throw a good party for microorganisms. Because when you compost, you are throwing a party for other living organisms.

Just like human parties, you want to serve the right food, invite the right guests to ensure good “chemistry,” and make sure everyone is comfortable and having a good time.

Before you can understand how to speed composting, it helps to understand the three basic phases of composting. Once you understand the phases, you can try to maximize the amount of time your composting pile stays in the middle, speediest composting phase.

Let us jump right in and talk a bit about the social lives of your new “friends.”

The Stages of Composting

Photo by Richard Horvath on Unsplash

People have been known to come to blows over whether there are 3 or 4 stages of the composting process. We here at R&R are not afraid of a fight, and damn it, there are 3 stages of composting (ok, we honestly don’t know, but we like the number 3 better).

To keep it simple, a compost pile basically has 3 phases that look a little like a bell curve – the warm-up phase, the hot phase (hint: prolonging this phase is how to speed up composting), and the cooling or curing phase.

During the warm-up phase, your guests have started to arrive at the party. Similar to human parties, the early-birds who show up at your door 5 minutes early to the party are typically a calmer bunch.

The warm-up phase is dominated by mesophilic bacteria that break down sugars inside your compost pile and give off heat. As those bacteria start to give off more and more heat, the temperature rises.

Now your compost bin is ready for the guests of honor, ushering in the hot phase of the party.

As Nelly Said, It’s Getting Hot In Here

The hot phase is known in scientific circles as the Nelly phase, after the rapper Nelly (disclaimer: the preceding sentence is completely untrue). This phase is when your compost pile really starts rocking. This stage is dominated by thermophilic bacteria and as their name suggests, they like it hot. This is the stage of composting when more complex materials are broken down.

During the hottest stage of composting, your compost pile can reach temperatures of 140 degrees Fahrenheit. This is really hot! It is hot enough to kill pathogens, kill weed seeds and is above the recommended setting on your hot water heater!

According to the Consumer Protection Safety Commission, tap water at that temperature can deliver 3rd degree burns with only 6 seconds of exposure! We do not recommend sticking your bare hands deep into a hot compost pile, but mostly because it’d be a little gross.

If you are a real science nerd, a characteristic we respect, you can buy yourself a compost thermometer. With one of these bad boys you can experiment with your technique and see what temperature your compost pile reaches.

There are both digital and analog thermometers available (we have not reached this level of compost nerd-ness and cannot speak to which one is the best but analog compost thermometers are much more affordable).

The final phase, the cooling phase, your thermophilic friends can run out of food (what kind of host are you!?), and the mesophilic bacteria take over again to finish up the scraps and leftovers.

But here in lies the secret of how to speed up composting: take care of your guests and prolong the “hot phase” of the party as long as possible.

Speed Up Composting By Keeping Up the Heat

The things you need to do to ensure a healthy compost bin are the same techniques for how to speed up composting. The only difference is you save up your materials and add them all at once.

You also focus on maintaining the optimal mix of factors to prolong the middle, hot phase of composting. This approach is often referred to as hot composting.

The factors you need to focus on to maximize the heat of your compost bin:

  • The right balance of materials
  • Properly sized (that is smaller) material to maximize surface area
  • Air/Oxygen
  • Moisture
  • Turning the pile (which basically is a way to maintain balance between the factors above)

(We assume you already have a compost bin, but if you are in the market for one, you can read our comparison of compost tumblers vs. compost bins with some recommendations here.)

Maintaining the Right Balance of Ingredients

Photo by Aziz Acharki on Unsplash

The optimal ratio of carbon rich or “brown” materials to nitrogen rich “green” materials for your compost bin is 30 to 1? That is by WEIGHT! Be mindful of adding too much “green” nitrogen rich sources. This includes all those veggie scraps you are adding day after day.

It can be challenging to find 30 times more carbon rich materials. One option is to use all that carbon rich junk mail, newspaper, and cardboard that shows up on your door step each day. You need to shred it though, read here about doing it the right way.

Leaves in the fall are a good source of carbon rich material. However, you need to shred them first or you can get an anaerobic compost pile once those big ole’ leaves get a little wet. 

When you add big fat leaves that aren’t shredded, especially in large quantities, it is like throwing a heavy wet blanket on that rocking microorganism party in your bin – don’t be a wet blanket and ruin the party.

Other good carbon rich materials include paper towels, saw dust (use only non-treated wood though), hay, and pine cones. However, depending on your situation, it can be hard to find those materials in ample quantities.

Expanding the Dance Floor: Increasing Surface Area

Is this party analogy getting tiresome? No? Good, because we got more. Just as moving some furniture out of your cramped living room will allow more dancers to cut a rug (as all the cool kids say nowadays), expanding the surface area of your ingredients invites more bacteria.

It is simple physics and similar to the warning you get when cooking – smaller pieces of food can fit more salt, it will have more “sides” and thus allow more salt, or in our case, bacteria, to attach to the side.

How do you accomplish this? Make sure you cut your ingredients down into small pieces as you add it to your compost pile, including your veggie scraps as well as any carbon rich materials you add.

This means ripping up those paper towels (yes you can compost paper towels with a few exceptions), pieces of cardboard, junk mail, and newspaper. Or shred them up!

Working In Batches To Create a Big Bang

To get the temperatures really hot in your compost pile, it’s best to gather all the material and put it in your compost bin all at once. This is often referred to as batch composting.

Make a pile of carbon rich browns while you collect up nitrogen rich greens, possibly freezing bags of vegetable scraps to combat any smells and slow down the decaying process until you’re ready to put it in the compost bin.

Adding all your ingredients at once, you are attempting to reach maximum temperatures as fast as possible. You could have usable compost in as soon as 6 weeks.

Hot composting will also result in more uniform, attractive looking compost.

On the downside, according to the book, Easy Compost when you hot compost you end up with less nitrogen and some of the organisms that help suppress disease will avoid those high temperatures in your compost pile.

Increasing Oxygen Speeds Up Composting

Air is a key ingredient for your little microscopic, garbage eating friends. One technique to speed up the compost cycle is to get more air flowing inside your compost pile. There are a few ways to do this.

First, simply turning your compost pile will deliver more air to your pile or your compost tumbler. Using a large shovel or garden fork will do the trick if you have a compost bin. Try to mix the material from the outside of the pile towards the hot center too, adding fuel to the center of activity.

Turn your pile every few days if you really want to speed composting up. You’ll introduce more air, ensure proper mixing of material, and spread moisture around, maximizing the fuel available to organisms inside. This keeps your compost in the thermophilic phase, which is really how you speed composting up.

Many people strategically add materials to their compost bin that will create pockets of air, such as pine cones, small finger-sized sticks, or other bulky organic materials. When you add these to you pile, you allow air to flow inside the compost and feed the organisms, especially the aerobic bacteria.

Tools and Techniques for Increasing Air Flow in Your Compost Pile

Michelle Balz in Composting for a New Generation has a nice DIY hack to increase airflow in your pile. You can find an illustration of her recommended technique here.

By adding a tube of PVC pipe with holes drilled into it, or a rolled up piece of chicken wire fence, you can create the equivalent of central air in your compost bin, delivering fresh cool air to your hard working bacteria on a constant basis.

Finally, you can purchase a tool designed specifically to aerate your pile, such as the one pictured below from Amazon.

Frankly, this is completely optional and not absolutely necessary. However, if you happen to suffer from back issues or otherwise don’t want to struggle with reaching in and turning your compost pile with a shovel or fork, this tool will definitely help.

Compost Speeds Up Plant Growth

When you speed up composting cycles, you get compost into your soil faster. And guess what else speeds up? Plant growth.

Studies have found that by adding compost to soil, and the humic acids that come with it, you actually speed up plant growth.

The Rodale Book of Composting explains that even at low concentrations, adding compost to your soil will speed up growth, especially at the early stages of growth.

We recommend a yearly compost harvest, at least, strategically timed for the late winter and early spring. You should clean out your compost bin, spread the compost around your garden, and prepare your soil for the spring burst of growth!

When you clean out the fully decayed compost, you also prepare your bin for the warmer season, which will naturally speed up composting in your compost pile.

Cold Composting: Lazy and Carefree Composting

alternatives to how to speed up composting
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We’ve talked a lot about hot composting, which makes sense because this post is about how to speed up composting.

But we would be remiss if we didn’t mention cold composting. This is a lazy person’s composting strategy, one that we wholeheartedly endorse.

Framing the question as hot vs. cold composting is a little misleading. They are basically the same thing. Both approaches harness the same decomposition process, the only difference is the amount of attention and time you need to devote to it, and of course the length of time to break down all the ingredients you’ve put in your compost.

When you cold compost, you can just be a little more passive and less obsessive about what you’re throwing in.

Cold composting is extremely simple. You still focus on the same factors that make for a well-balanced and healthy compost pile. But you optimize it over the long haul, letting your compost pile break down the material slowly over time.

Cold composting isn’t even very cold, The name is really a misnomer. Cold compost piles can reach 100° Fahrenheit. Hot composting is simply cold composting techniques optimized for reaching slightly higher temperatures and speeding up composting.

Disadvantages of Cold Composting

The disadvantages of cold composting that you should be aware of include the propensity of a cold compost pile to have materials that are not fully decomposed. This can manifest itself in banana peels or apple cores showing up in your compost when you spread it on the garden.

Although aesthetically unpleasant, having chunks of slightly decomposed organic material will act like a slow release fertilizer, breaking down over time and releasing valuable nutrients into your soil. But it can be a little gross.

The other issue is you will find that cold composting allows seeds to survive. We recommend avoid putting weeds into a cold compost pile, since you will be eventually spreading lots of weeds into your garden.

A less negative version of this problem is the franken-vegetables that will pop up in your garden occasionally from all the seeds that hitched a ride on your vegetable scraps. Last year we had a little mini pumpkin grow in our garden. And other random veggies that we didn’t intentionally plant have popped up year after year.

Our partners over at the Creative Vegetable Gardener suggest that these franken-vegetables can be hit or miss. Some of those seeds come from vegetables that may not be ideal for your climate, especially fruits and vegetables that have been shipped across the globe to your grocery store.

That said, it can be fun to see what happens and what mystery vegetable you end up growing.

How to Speed Up Composting in Winter

If you happen to live in a part of the world where it never gets cold, you can skip this section and go back to frolicking in the sun (grrr, we are so jealous!).

As you can imagine, reaching very high temperatures in your compost pile during the winter is going to be difficult. It is unlikely that you will be able to reach the levels necessary for hot composting.

However, you definitely can continue to compost throughout the winter, it will just be slower.

In Composting for a New Generation, Michelle Balz has some tips for composting throughout the winter. One of her suggestions is to use hay bales placed around your compost bin to insulate it. This will help maintain a higher temperature despite the cold.

She even suggests using snow, packed around your compost bin, as insulation.

Hot or Cold, Composting is Fun and Easy

In the end all that matters is that you compost your waste matter and keep it out of the landfill. Though there are some challenges to composting, you can overcome them, we believe in you!

The good thing is, whether you decide to try your hand at hot composting or take the easy route and cold compost, the factors that make for a healthy compost are the same.

Focus on balance – air, moisture, ingredients – and you will be producing nutrients for your plants and newfound microscopic party-goers in no time, plus helping the planet for humans too!

Further Reading and Sources

Composting for a New Generation is a fun read and covers everything you need to know about composting, including how to speed up composting.

Easy Composting is a short but comprehensive book that does a good job delivering just the right amount of science in addition to very helpful advice.

The Rodale Book of Composting is kind of like the composters Bible, it is chockfull of facts, techniques, and interesting info on the science of composting.

Both books get an enthusiastic recommendation!

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