yes, you should keep it covered.
I was thinking for in the pot only. I turn over a stone in the flower bed and can get castings off the back. I'm in the south and don't put chemicals on the yard anymore, I gots worms everywhere. Need to get a nice bed for them to make them in one spot now. And keep the dogs from digging in it. I really appreciate your help. I may cut the bottom off and old planter and slowly raise the dirt level in it. Now to find a place for it! Should the top be covered to keep rain out?