Indoor Gardening and Houseplants: Does anyone know what this is? , 2 by martyR

martyR wrote:
I first noticed this white growth around the back edge of the pot at Christmas time. The plant [Peace Lily
Spathiphyllum] seems healthy, some minor tip burn and a few leaf holes; these I attributed to being in too much sun [ southern window ] and the white fly or aphid problem I am having with my oxalis. I moved it to a northern facing window in the fall. The white substance is easy wiped off with dish soap and water. This plant was outside this summer and thrived; so much so that i repotted it before bringing it in. So I am fairly sure the pot and soil was clean.