I buried a 30k bell bag in a glowy spot in my town yesterday... and it died today! I'm sure it was on fertile soil and it didn't have any trees next to it for at least 3 spots. D:
You need to use a gold shovel first of all. I'm also pretty sure the higher the amount the more likely it is to grow. I buried a 99k bag a couple of times and it grew fine. ^^