Here's a FAQ on DE
Diatomaceous Earth FAQ
Question number four is about breathing it in and what different kinds of DE are harmful and which are not. From what it states food grade DE should not be harmful - then again, who knows if it's true or not.
---------- Post added at 05:36 PM ---------- Previous post was at 05:11 PM ----------
I guess the best way to do this would be to go outside with the plant, put on the DE with a brush and sprinkle some on the soil so the most gets on the plant and less gets in the air. Then shake it when outside to get rid of excess DE and bring it inside.