^ In doing some light digging, I came across some surface roots that broke away, so I'm a bit leery of turning the soil much. A friend had recommended using a gardening hand rake, about the size of a spade but with spikes. I may give that a go and just gently puncture some holes into the soil for aeration.
I am trying to do watering on both ends--mostly container filling but also some periodic water from above during long stretches between rainy days (we had a deluge about 9 days ago but hardly any rain since). I also re-read the packaging for the topsoil which said it has fertilizer and peat moss mixed in... so it seems like the mistake wasn't too bad.
Anyway, my fertilizing effort being a little too light resulted in a rather small first tomato. It's a Black Krim and not even as large as a tennis ball! But I'm hopeful the ones to come will be larger.