If there is one thing I have a lot of, it's decomposing leaf litter
(aside from shade and pine straw).

I've never thought of using this as a mulch (I'm more concerned with
moisture retention than weed blocking). Now, I wonder if this may be a
good thing for some plants and perhaps because of the micro-organisms in
that, not so good for others.

There are a *lot* of earthworms in there. I was thinking maybe the
tomatoes and peppers, and not the cucurbits. Current strategy has been
cedar mix mulch. My impression is that newspaper much is more for weeds
than water retention, am I wrong?

Jeff