Have you ever wondered what a 3 bin compost system is? And how is it the same or different to a single compost bin, compost tumbler, or hot composter?
This article explores the 3 bin system; the first holding raw organic waste, the second partially decomposed and the third finished compost.
What is the 3 bin compost method?
The three-bin composting method is a systematic approach to composting that involves the use of three separate bins or compartments to manage the various stages of the composting process.
This is how this system typically works:
- Bin 1 – Collection:
- Fresh organic waste materials are collected in the first bin.
- Kitchen scraps, green materials (nitrogen-rich), and brown materials (carbon-rich) are added to this bin.
- Materials in this bin are in the early stages of decomposition.
- Bin 2 – Turning or Maturing:
- Once Bin 1 is full, the materials are transferred to Bin 2 for further decomposition.
- Turning or mixing of the compost occurs in this bin, providing aeration and facilitating the breakdown of organic matter.
- The compost in this bin is in the maturing stage and continues the decomposition process.
- Bin 3 – Finished Compost:
- Bin 3 contains fully matured compost that is ready to be used in gardens or on plants.
- The compost in this bin has completed the decomposition process, resulting in a nutrient-rich and stable soil amendment.
The three-bin composting method allows for a continuous cycle of composting. As new organic waste is added to Bin 1, the materials in Bin 2 undergo further decomposition, and the finished compost in Bin 3 is ready for application.
This system helps ensure a steady supply of compost for gardening or landscaping needs while efficiently managing the composting process.
Additionally, it provides flexibility in turning and managing compost at different stages of decomposition.
You can have a cold or hot composting 3 bin system. In a hot composting system the compost will be turned between the bins more frequently than in a cold system.
What are the benefits of a 3 bin compost system?
For me these are the most important benefits over a single bin system:
- Continuous composting. While one bin is actively receiving fresh organic material, the other 2 are continuing with the decomposition process.
- Faster decomposition. Turning the compost from one bin to another introduces oxygen, accelerating microbial activity and speeding up decomposition.
- More organized. It is easier to manage and harvest finished compost without disturbing the ongoing composting process.
- Space utilization. A 3 bin system is space-efficient and can be set up in a relatively small area.
- Scaleable. If the amount of organic material available increases, additional bins can be added to the system.
What is the easiest home composting system?
The absolute easiest in terms of maintenance is a single cold composting pile. HOWEVER the drawback is that it takes a long time to produce the compost (6 months to 2 years). It can be untidy and it takes up space.
Don’t forget that the easiest is sometimes the system that you have chosen to meet your own needs.
A well organized 3 bin system does require more work in turning than a single bin, but you get easily accessible, fully decomposed compost out of the third bin.
And if you only produce a small amount of waste from your kitchen and garden, then a compost tumbler might suit you better and be easier to manage.
How often do you have to turn compost?
As with everything compost it depends. On the size of the pile, on the time of the year and on how quickly you need your compost.
A couple of key ways to decide:
- If you are hot composting, the temperature will rise to something too hot for your hand and then fall. Turn when the temperature starts falling (every few days).
- If you are cold composting, look out for some signs. If it becomes compacted, develops unpleasant odors, or appears overly wet, you have left it too long and it needs turning. If you have built it well with a mix of greens and browns it may not need turning at all.
- Tumbler can be turned every few days.
Turning compost adds oxygen to give the microbes a boost. But turning too frequently can be a bad thing. You have to find the balance with your pile.
When should I empty the compost bin?
In a 3 bin system, the third bin is for finished compost. This can be emptied when it is needed in the garden. It does not need to be emptied in one go.
This may not work if the third bin is needed for turning from the first 2. In this case the compost can be stored elsewhere for use in the garden. Make sure to keep it moist to keep it alive.
What is the best to put in the bottom of the compost bin?
At the bottom of the compost bin the focus should be on aeration and drainage. A layer of twigs and branches, or bulky shredded cardboard or newspaper will eventually turn in to compost.
In the short term these will ensure that the materials at the bottom do not get waterlogged and there is sufficient air to encourage the microbes.
Why put cardboard under the compost bin?
A layer of cardboard can be put under a compost bin as it will keep the weeds down when you first start. Over time it will rot down and become part of the compost.
What are the 3 main compost ingredients?
For successful composting you need food, air and water.
What is a good compost accelerator?
Compost accelerators speed up decomposition by providing additional microorganisms and nutrients.
Old compost or well rotted animal manure (horse or cow) is a great accelerator. It’s already teeming with beneficial microbes, ready to get to work.
A couple of others to try would be used coffee grounds, seaweed, human urine and yeast.
When using accelerators, it’s important not to overdo it. Too much of any one material can upset the balance of the compost pile. Aim for a mix of green and brown materials, keep the compost moist but not waterlogged, and turn the pile regularly to ensure proper aeration.
Can you put grass clippings in compost?
Yes you can put grass clippings in compost. Just remember that they are greens, and when you add grass clippings there is usually quite a pile of them. They need to be balanced with adding browns (cardboard, autumn leaves) to keep decomposition running smoothly.
Can compost bins be in the shade?
Yes they can be in the shade, but heat from the sun can help to speed up the decomposition. So compost bins in the shade may be slower to produce compost.
Can compost bins sit on concrete?
Hot composters (1 or 3 bin systems) and tumblers do not need a connection to the earth. They can sit on concrete.
A cold composting 1 or 3 bin system will benefit from a connection with the earth for worm activity and drainage. These would ideally not sit on concrete. Having said that, if there is nowhere else suitable it is better to compost on concrete. You should design good drainage and add a few spadefuls of soil to the bin to get the connection to the soil.
This article has explored the three bin compost system. What do you use for composting at home? I would love to know in the comments below.