Worm Casting for SS

I got my charge pack in the mail this week and I have all my base soil buy I went to look for the worm castings I only found Black Golds earthworm casting blend is this the right stuff or do I need pure worm castings? I need to check HD and lowes stores

check a plant shop or hydro store. They should have straight castings. Black gold is a good brand, but you want pure castings.

Thanks Oriah I found them at a local nursery