What clues are leading you to think you have a shortage of phosphorus and potassium?

What is actually growing well?

How long do the acorns take to break down/be eaten after a normal crop has fallen? Do they go mouldy? Get eaten by grubs? Taken away by rodents?

If you confined them in a compost heap with mixed leaves - a slow damp heap over the winter - what do you want to use that humus for? (I'd probably think about azaleas, rhododendrons, some of the acid-soil berry bushes. I'd also run a pH test - even with one of those soil tester kits to check it out.)

If you mushed them then that oily flour is probably going to be a starter bed for various fungi and bacteria which might not be too welcome in the garden. At the moment there'll be an ecosystem in place to handle the leaves and fruits from the oaks that is mostly benign. You might choose to 'do more of the same' but not quite so 'spread out' as at present. (Less work...;-D )

Thanks for the headsup. I was a little worried about the oil, acorns being nuts. I looked at that page with the pictures of mineral-deficient leaves, and my plants don't look to have any of those symptoms, but some of the leaves that have developed since I started using a fermented molasses foliar feed (I regret letting myself get talked into that) seem softer (even mature leaves) than the ones before, so I wonder if I've caused an imbalance.

And you're right - I was thinking of my blueberries.