You find this discussed in great detail over on the Container gardening forum In fact you'll find a great deal of info on your non-tomato questions discussed there as they focus on container gardening. Check out this discussion of bark fines.

Dave

Here is a link that might be useful: Container gardening discussion on bark fines

Thanks, Dave. I was wondering this too.

I'd consider bark fines as being about the size of one's finger nails...pinky to thumb. What are typically sold as "mini pine bark nuggets' are too big.

And don't forget that we're talking about conifer bark...pine or other conifers. Not plain wood chips.

Thanks. This particular brand is fir bark, which I think is a conifer, but not a pine. The chunks looked to be about the size of my fingernails, maybe a bit larger, but I will check again.