How many spheres can be buried in the Sinnoh underground at once?

Question

In Pokémon Platinum I thought it would be funny if I buried a sphere on every single tile in the Sinnoh underground. Then in the future I’d have an endless supply of size 99 spheres! But I noticed that if I placed to many traps old traps would disappear. Will old spheres disappear if you bury to many of them like how the traps disappeared? So how many spheres can be buried at once? Could I actually achieve my dream of burying spheres in every tile of the underground?

Answer 1

In all Gen IV games, the limit is 100 buried Spheres. You can bury more, but the oldest will start to disappear.

Sphere (Bulbapedia)

Answer 2

From what I've gathered both from experience and research, there isn't actually a limit (although nobody has attempted to bury a sphere in every tile).
However, some players noticed that buried spheres may disappear in Diamond/Pearl if they've buried a great deal of them. As far as this goes I can't find anything on an actual limit, as it just seems to be random after you've buried enough, much like traps disappearing.

But since you're playing Platinum this shouldn't be a problem anyway.
Bury to your heart's content!