A cold compost heap can take months or even years to reach perfection.
The good news is that you don’t have to wait that long. In fact, one composting system produces finished compost in just 14-21 days. (You’d ideally let it mature for a while before using it for the first time!)
If you’re as impatient as I am, and are wondering how to speed up your compost heap, you’ll find the following 18 tips will help you really accelerate the process!
1. Add a layer of sticks and twigs at the bottom
Placing a layer of twigs or sticks at the bottom of your compost pile traps air inside the compost pile. This enables aerobic, or ‘with air’, composting to take place and helps drain excess water.
Aerobic composting is faster than anaerobic composting, reduces odor and is better for the environment.
2. Add old compost/soil
By adding in a little bit of old compost or some soil, you will ensure there is plenty of the right type of bacteria to start the composting process.
(This is controversial – but a lot of professional composters swear by it!)
3. Use a hot water bottle to kick-start your compost
This is a tip I picked up when I received my Hot Bin compost bin.
It came with a hot water bottle. After adding a sack of stockpiled compost material, I filled the bottle up with steaming hot water and dug it into the top of the compost.
Nothing happened the first day. After adding a second sack of material I repeated the process the next day. By the third day, the compost was hot, reaching 50 degrees celsius.
4. Use a compost duvet
Hot water bottles add warmth, and compost duvets maintain warmth, helping to keep the optimum temperature for bacteria and fungi to break down organic materials.
Some compost bins, such as the Green Johanna and its winter jacket, have specially made compost duvets. Alternatively, you can buy compost duvets or make your own with materials such as old carpet or bubble wrap.
Green Johanna Duvet Experiment
The folks over at Green Compost Systems did an experiment to measure the impact of using a duvet.
They found that duvet lifted temperatures 30 to 60 degree Celsius – even in the coldest winter months.
Also see: How to Insulate Your Compost Pile or Bin
5. Turn your compost
You can also turn your compost to introduce more oxygen into the mix.
Some systems recommend turning your compost heap every day or two (see the Berkeley method below), but even turning it once or twice will help speed up the composting process.
If you do decide to turn it regularly, considering getting a compost fork to help make the process easier.
6. Create Free Air Space in your compost
Older composting guides rarely mention Free Air Space (FAS) in composting.
But FAS gets plenty of attention from professional guides and compost researchers.
While it may not be well known, composting systems which utilize FAS are very effective.
All you need to do is introduce bulking materials that create air pockets in the compost.
The highly effective Hot Bin compost bin uses semi-decomposed wood chips to generate FAS which enables air to flow through your compost.
7. Adding nitrogen-rich materials
If your pile is slow, the carbon: nitrogen ratio might be wrong.
The microorganisms in compost need both nitrogen and carbon to work. If there is too much carbon, the process will slow down.
To speed up the process try adding ‘greens’ – items that are high in nitrogen, such as grass clippings or manure.
8. Getting the moisture ratio right
Research by Tiqua et al shows that when moisture levels are too high, the heat of the compost heap drops, slowing down the composting process.
Indeed, another study found that lowering moisture content from 66% to 61% increased the temperature of a compost pile from 55℃ to over 75℃.
One reason for this is that if your compost is too wet, water can fill up the free-air spaces. This reduces the oxygen available to microorganisms and slows down the composting process.
If you don’t have the tools to measure moisture levels, simply take a handful of compost and squeeze it. It should have roughly the consistency of a squeezed-out sponge.
If it’s wetter than that, simply add a dry material such as shredded paper or torn-up cardboard to soak up the excess moisture. It’s also worth covering your compost to protect it from rain.
Compost can get too dry too.
When I turned my large compost heap last summer, the centre was dry despite recent downpours. As I turned it, I sprayed each new layer with water to increase the moisture level.
Do be careful if your compost heap is dry and musty. Musty compost heaps can release harmful bacteria when turned – another reason for ensuring the moisture content in your heap is correct!
9. Compost activators
There are many compost activators available. If your compost is too high in carbon, adding a high nitrogen activator can help speed it up.
However, I personally don’t use them, as there are a number of free alternatives you can use.
I’ve personally found chicken manure to be brilliant. Not everyone has access to this, but you can also use other high-nitrogen sources such as nettles, grass or urine to help get your compost heap going again.
What I do use is a compost thermometer. I find this useful (and fun) because it allows me to measure the effectiveness of adding different materials.
Of course, there are many different factors that go into how hot a compost heap gets.
But over time, as you add materials and measure the temperature, you start to get an idea of what works best.
10. Add easily digestible materials
Some materials compost more easily than others. Materials such as wood and leaves are high in lignin, which is difficult to compost, especially when this material is large in size.
Other materials, such as grass clippings and shredded paper, compost a lot faster.
By ensuring you include some easily digestible materials, you can speed up composting.
11. Reduce material size
The larger the compost material, the less surface area there is for bacteria to work on. By reducing the size of the compost ingredients, you can make it easier for bacteria to break them down.
If you have a bucket of compost ingredients, consider roughly chopping it up with a pair of garden shears.
For larger amounts of material, you can use a lawn mower to chop up material, while a compost shredder can work wonders with woody material.
12. Increase the volume of your pile
Large compost heaps work better than smaller ones.
With a small pile, the environment outside the pile can cool the contents down quickly. So if you’re using a compost heap rather than a bin, increasing the size of your compost heap will speed up the process.
A pile of at least 36” x 36” x 36” works well. Pallet bins also work well for this, as they have the right size for generating heat.
13. Use the Berkeley method
If you have a larger amount of material available you might want to consider the Berkeley method, designed by Robert D. Raabe of the University of California.
This method involves building up a large compost pile of small materials (1/2 to 1-1/2 inches in size) and mixing roughly equal amounts of greens and browns. The compost is then turned every 1-2 days.
The results? Compost in 14-21 days.
(As mentioned before, I wouldn’t use fresh compost – I find it best to leave it to mature before using.
When I used fresh compost from a municipal dump, the results were pretty poor. The same compost a few months later performed brilliantly.)
14. Insulated bins
Of course, most gardeners don’t have large amounts of material waiting ready to be composted.
However, insulated bins such as the Hot Bin enable you to achieve rapid composting (30 to 90 days) with smaller amounts of compost material.
15. Add Biochar to your compost
Biochar is charcoal which is sometimes used as a soil amendment.
Research by L M.Sánchez-García found that adding 3% biochar to compost materials could increase composting speed by 20%.
Do note that Biochar is controversial when it comes to soil amendment, and the Royal Horticultural Society advises only using FSC-certified Biochar which is made from European hardwoods.
Learn more: How Biochar Improves Compost Speed and Quality
16. Use worms to finish off the process
Is compost cooling down?
Hot compost is too hot for worms, but as it cools down worms will move in, further improving the quality of the process.
You can always speed up this process by attracting and/or adding plenty of compost worms.
Compost worms (Red Wrigglers) can eat their own weight in decaying material in a single day, pushing it through a gut that contains 1000 times more microbial life than the food it consumes.
Worms also help remove pathogens from compost. While worms won’t, unfortunately, produce overnight results, the longer they have to work on your compost the better it will be.
17. Use compost technology
If you want to get high tech, use compost technology to monitor oxygen, temperature, moisture and more – AND calculate the carbon nitrogen ratio of your organic material.
Nowadays, you don’t even need to use multiple devices to do this, as all-in-one solutions are available that connect directly to your phone.
To learn more, see 7 Ways to Use Compost Technology to Speed Up Your Compost.
Don’t forget to let your compost mature
Despite everything you read online, compost is not ready to be used as soon as it has cooled down. Here’s why, and how long to leave it to mature..
It took me a while before I got my first hot compost heap, so don’t be discouraged if it takes you a while too.
Remember, composting is an art as much as a science, and one of the best ways to learn is to experiment.
Yes, heat speeds up the composting process.
Hot composting is a method of composting that involves actively managing the compost pile to maintain high temperatures, usually between 130-160°F (54-71°C).
These high temperatures help break down organic matter more quickly than in a cold compost pile. See the Five Rules of Hot Composting for more information.
It is more challenging to produce compost quickly in a cold climate as the colder temperatures slow down the composting process. However, you can still speed up the process by insulating your compost or using an insulated compost bin, adding hot water bottles or compost duvets to maintain warmth, and using smaller, easily digestible materials.
The Berkeley method of composting is also effective in producing compost quickly in colder climates.