Question, egg shells

[BURR]

The guy across the street here in the Philippines puts egg shells on top of his Orchids.
He doesn't break them in small pieces he just lays the shells in half's on top of the plant.

Anyone heard of this.

He doesn't have any blooms and I have 20 out of sixty in bloom. I use fertilizer and insecticide weak weekly.

I can't read the bottle because the labels are gone. I also moved them under the eves because of the rain and people stealing them off the fence.