No, unfortunately not. Sawdust is too fine and wood shavings are not thick enough to be a substitute for woodchip and both lack adequate water absorption properties to replace paper.
How Does Woodchip Help Composting?
The job of woodchip is to create air pockets within the waste as it is added to the HOTBIN. These pockets allow air to circulate through the HOTBIN feeding bacteria with oxygen and keeping them composting aerobically. Without these air voids and access to oxygen, bacteria will start composting anaerobically which means a colder bin and often bad odours.
If you decided to use wood shavings or sawdust these would likely block aeration in the bin because the particles are so fine. The results of using both wood chip and sawdust in the HOTBIN is also discussed alongside why the carbon to nitrogen ratio isn't as important in the HOTBIN as it would be in other composting options.
I Don’t Want to Add Woodchip
Adding woodchip is the trade-off for not having to turn and tumble a compost heap.
One of the most common causes for a HOTBIN not getting up to temperature is a lack of woodchip (air voids) and/or shredded paper. Insufficient woodchip prevents the contents from being sufficiently aerated whilst a lack of shredded paper can result in the contents becoming overly wet.
If you do not add woodchip or a suitable alternative the HOTBIN is unlikely to operate as a hot composter. It is important for a woodchip to have a certain particle size; sawdust for example is so fine it will just simply fill those voids blocking aeration.
Can Sawdust Replace the Job of Paper Instead?
Although sawdust does have some water retention properties, unfortunately they are not sufficient to control the moisture levels in the HOTBIN which is why we recommend shredded paper. The fine nature of sawdust also means that when it becomes wet it has the ability to clump together forming a damp impermeable mass in the HOTBIN.
Struggling to locate enough shredded office paper, here are a couple of alternatives.
Can I Compost Pet Bedding?
Pet bedding (wood shavings and sawdust) can be added into the HOTBIN but only when it’s hot (40-60°c) and in small quantities mixed with other waste. The key here is to remember not to restrict airflow so don't forget to mix in paper and woodchip too.