Compost and soil-based mixes perform very differently in containers than in beds. They compact, tend to drain poorly, develop root rot, and can develop damp-off and other fungus disease issues. While established plants can cope with some of those stresses, seedlings and young plants cannot. And while plants in large big beds can cope with those issues, plants in containers often cannot.

For those reasons, using anything other than one of the many sterile, soil-less peat-based growing mixes in containers, especially small containers, is not recommended.

You can find many more discussions about this over on the Container Gardening forum here if interested as well as in this forum's FAQs..

Dave

PS: as for your raised beds with"organic compost, black 1/4" mulch, cinder sand, and mushroom compost" hopefully there are other ingredients as well, a source of minerals, some soil. etc. as you would be essentially growing in straight compost which can be very problematic.

Thanks! Yes, we're just amending the beds with it. We also have soil, manure, leaves, old straw.