[MadCow333]

Some of my containers I am sure date back to 2016 and were used 5 seasons. They started as Promix BX and might have odds and ends of compost, potting soil, or garden soil mixed in over the years to top off the containers if the level sank. Each spring, I take a shovel and break up the mix. Sometimes, if a container seems firmly packed, I dump that entire pot or more than one pot into a Rubbermaid storage tote and break up all the clods and mix in some fertilizer, then shovel it back into the containers. I've never bleached or otherwise treated any "soil" for diseases and haven't had any problems with reusing the same mix. These are large containers 24" diameter and plastic. They sit outdoors all winter because they are heavy and bulky to store, and I just don't move then very far from their summer location because they're a lot of freight to haul.