Can You Compost Cardboard?

Yes, cardboard can be added to the compost pile. Cardboard would be considered a brown compost material (source of carbon).

Shred the cardboard into smaller pieces before burying it in the compost pile. This will speed up the composting process. You can also use cardboard as mulch if you have a lot left over.

Reference: https://web.extension.illinois.edu/bdo/downloads/55835.pdf

Cardboard Compost