One of the more common bedding materials used for vermicompost systems is cardboard. This post will examine the pros and cons of using cardboard in a vermicomposting system.
Most indoor vermicomposting systems will utilize cardboard as a bedding or “brown” material. The most common type is corrugated cardboard which is basically three layers. Corrugated cardboard is typically made up of two layers of flat boards and a fluted center sheet. Regular cardboard is basically a single flat board (think cereal boxes or wine box inserts).
For vermicomposting, it is probably best to avoid using cardboard that has a glossy side to it. I avoid using cardboard with a glossy coating such as cereal boxes. Also, I try to remove all the tape and packaging labels before using.
There are a two main methods for preparing cardboard for bedding:
- Shred the cardboard with a paper shredder
- Rip up cardboard in large chunks and soak in water
Both methods can work well for vermicomposting. I wouldn’t say one method is better than the other as it is mostly personal preference.
Shredding through a paper shredder
Most paper shredders can handle a single layer of corrugated cardboard. Shredding is easier if the cardboard has a lower Edge Crush Test (ECT) rating. Most boxes will indicate what amount of weight the box can withstand. The lower the rating, the better for running through a shredder.
Shredded cardboard benefits:
- Greater surface area for microbes to break down quicker
- Provides airflow in a system (the corrugated cardboard allows air to pass through the fluted sections)
- Absorbs moisture quicker
Shredded cardboard cons:
- Time consuming to run through a shredder
- Unless you have an industrial shredder it takes time to shred
- Uses energy to process
- This will actually cost you some money to process. It’s probably not a lot of money but you need electricity to run the shredder
- Need a shredder that can handle at least 12 sheets
- This may seem obvious but you would need to purchase a shredder.
Rip and Soak Method
The second method involves ripping cardboard with your hands and placing the torn pieces in water. As the cardboard soaks in the water it becomes very easy to tear into smaller pieces.
Rip and Soak Benefits:
- No need to buy a shredder (assuming you don’t have one)
- Easy to do
- Soaking the cardboard makes it readily available for the worms
- Less time spent preparing
Rip and Soak Cons:
- Can be messy if too much water is added
- Can turn the cardboard into mush and may require a drying period
- This is more of a concern for a tote system as these systems tend to run wetter
- Less uniform bedding
I think both methods have their benefits but I tend to use a shredder to prepare cardboard bedding. I tend to make a large batch at once and store it for when I need it. The uniform texture makes it adding to systems a bit easier and is easier to mix with other bedding materials. Also, it provides an option to add dry cardboard to systems that may be a bit too wet.