Affordable and easy to maneuver, these containers have an airtight seal, which is usually meant to keep Fido's food fresh and lock in the odors. When repurposed for potting soil, however, a pet food ...

All you need is the bagged food item ... (PETE or PET) and are considered acceptably airtight. Once you start cutting up the plastic, though, you will have to test your container on your own.