Diatomaceous Earth and plant question

Hello. I'm completely new to this topic but read in one of Paul Wheaton's articles that food grade DE is a good ant deterrant around plants and potted plants. Here's my question. The article said that the DE only works when dry. How does one apply the DE to the base plate of a pot and not have it get wet? I assume that after each watering, the water drips down through the pot and onto the plate, ruining the DE.

Would someone please explain the usage of DE with a potted plant. Thanks!

I've only had mediocre success with DE when fire ants and other ants come to chew through the stems of young brassica transplants...a particular problem with fall plantings. Never thought that the dampening issue might be the problem. Rotenone dust seemed to work better. DE really shines as a leaf dust against things like flea beetles and to some extent, grasshoppers. Cut it 25% DE to 75% wood ash and you get almost as good control with a lot less DE!

Thanks for your reply but it didn't quite apply to my question. I asked how to combat ants when applying DE to the plates that potted plants sit on. The idea came from Paul Wheaton's article on the topic.