Question, egg shells
 

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.

I don't see what putting large pieces of eggshell on top of an epiphytical potting mix for epiphytical orchids will really do for them.

The egg shells have to be broken down in order for the calcium to be available to the plant. What I mean is, it's got to be able to decompose.

That practice is useless.

It's better off to use crushed dolomite pellets to provide calcium and magnesium. At least with this, the water will slowly dissolve the mineral over time and the plant can absorb what's in the water.

Unless...

You crush the eggshells into little tiny bits and grind them into a powder and sprinkle that eggshell powder onto a terrestrial mix for terrestrial orchids.