[dice]

The "mycorrhizae in containers" gives me an idea. If you have
trees that you have not treated by the end of the
tomato/vegetable season, you can dump out the container mix
from containers that had a mycorrhizae treatment around under
the trees, and the mycorrhizae should spread from the container
mix into the soil around the tree roots, thus recycling the
mycorrhizae that you used for the vegetables to treat the trees
in your yard. (Some trees are not colonized by mycorrhizae,
but that would be no different whether you watered in the
spores directly or let it spread into the soil from colonized
container mix.)