Black lines after using PackTextures()

I have a tiled based game and to increase performance I'm attempting to use PackTextures() to pack a lot of ground tiles into one texture and use the same material. I got everything working but my result ended up in black lines showing around the tiles. There are 6 different types of grass tiles, that are randomly chosen herein the picture below.

I tried adding padding to PackTextures with the same results. Does anyone know how to fix this?

Thanks!