I hilled up several potato plants with not mature
compost , still in very rough form. -- basically leaves and
clippings clomped together.

The plants began to die back, and didn't produce a lot of (red)
potatoes.

Did I do wrong by using that material to hill up?

IOW, is this post hoc, ergo propter hoc?

Or just coincidence.

TIA

--

Persephone
Not sure what you mean by hilled up, but it is normal to mulch potaoes with
straw, leaves, etc, Unlees you cover the entire plant, they thrive on it.
Potatoes are very susceptible to broad leaf weed killers such as 2-4D, If you
used lawn clippings from a treated lawn, it can cause a problem,