you cant its impossible
You cannot capture Bulbasaur in Diamond or Pearl (not sure about Platinum).
You cannot find bulbasaur on Pokemon pearl, diamond and platinum but you can transfer from GBA via pal park.
You cannot catch bulbasaur in diamond and pearl. If you have firered or leafgreen can set 6 Pokemon free in pal park and catch them there.
You can't find Bulbasaur in the wild on Pokemon Diamond or Pearl (not sure about Platinum).
get firered or leafgreen and migrate it to pearl after national pokedex
You can't, Bulbasaur is unobtainable. You have to trade, hack, cheat or get it from mystery gift.
You can't. You have to migrate pokemon.
Not really, you can get it on the game by migrating or trading do.
You don't.
Get an action replay, (if you can) go to where you have a list of pokemon you can get. Scroll down until you eventually come to bulbasaur. Have fun:^)
You can't regulary.You can only get bulbasaur from the GTS(Global Trade Station) or from cheating(Action Replay). ORRRRRRRRR you can migrate from Pokemon firered or leafgreen
you cant catch him you have to migrate him from the GBA Fire Red or Leaf Green