Woodchip is required inside the HOTBIN to help maintain airflow by creating a structure of free air spaces to allow a flow of oxygen to keep bacteria composting aerobically and to avoid a smelly putrid HOTBIN. Woodchip should be added every time you add waste into the HOTBIN.
Why Is Woodchip Needed in the HOTBIN?
The HOTBIN is an aerobic compost bin which relies upon composting bacteria being supplied with oxygen to efficiently digest waste into compost. Airflow (oxygen) is required in all compost heaps and bins to eliminate the need to turn the heap.
Woodchip is a bulky material that is used to supply oxygen and maintain airflow in the HOTBIN by providing a self-supporting structure in amongst the waste. When soft (non woody) waste breaks down, the cell structure is lost and the waste collapses into a mushy layer. Water is released from the cells and this collects within the mushy layer which quickly blocks airflow and turns the contents anaerobic with a putrid/rancid odour.
To explain the concept of the self-supporting structure, think of a jar, if this is filled with marbles there will be lots of gaps (free air spaces) however if we fill a jar up with sand there will be little to no gaps in the jar for oxygen to flow. So, it is really important to maintain an airflow structure using woodchip, which is bulky, inside the HOTBIN to promote airflow and keep the unit composting aerobically.
Can I Use Sawdust/Wood Shavings Instead?
No. It is important to not use woody matter that is not ‘fine’, such as sawdust or shavings as this will not create the self-supporting structure required to support the flow of oxygen inside the HOTBIN. Think of the jar filled with sand mentioned above.
Partially composted woodchip is our material of choice. This provides a good balance between providing the right structure for airflow and is reasonably well broken down in the final compost. Remember the purpose of woodchip is to aerate the waste so it may not always fully break down and some bits may require a second process. Sieving end compost can help identify those pieces.
When Should I Add Woodchip?
Every time you feed the HOTBIN to maintain the flow of oxygen around the structure of free air spaces (aeration). Mix it in with the fresh waste that you are adding.
As a rough guideline we recommend adding an additional fifth of woodchip to whatever quantity of waste you are adding. So, if you add 5 handfuls of veg peelings into the HOTBIN be sure to add 1 handful of bulking agent - you may wish to add a little more if adding extremely wet/mushy waste such as grass. Remember every HOTBIN is different due to the types of waste being added but the ratios advised are a good starting point.
Can I Make/Source My Own Woodchip?
Absolutely! Woodchip can be purchased from the HOTBIN shop or it can be sourced from a number of places, some at no cost!
- Make your own by cutting up twiggy plant material such as prunings and branches
- Use a shredder/chipper to reduce the size of prunings and branches at home
- Purchase woodchip from local garden centre or farm store (normally 75 litre bags)
- Check your local council, many shred trees and leave them piled locally
Is moisture a concern?
It is not essential for woodchip to be dry as it will still function as a method of creating and maintaining airspaces throughout the heap to improve airflow. However, if you are adding wet woodchip into your HOTBIN you should add an extra handful of card/paper to counteract the extra moisture. Keeping woodchip undercover, and as dry as possible, will remove the need for extra card/paper.
Whether from a garden centre, ourselves or another source, bagged woodchip can become damp for a few reasons; they may sometimes be subject to outdoor elements from storage and may become damp or in hot conditions the bags may sweat from the natural moisture content within.
Woodchip Tips:
- Try to keep woodchip or woody matter dry – store undercover away from moisture.
- Don’t be tempted to use it as a base layer when starting the HOTBIN.
- Remember, every HOTBIN is different, so you may wish to increase your ratio of woodchip in some circumstances.