have had good results from using grass clippings as you mentioned. I have also had success using leaves. I ask all friends who bag up their yard leaves (mostly friends with maple trees in their town yards) to give them to me and I put them on top of the grass clippings. I see worms galore in the spring. fyi. i, I want to use this for my container plants, using soda bottles with wicks buried inside the containers. I have some pretty pots to use as containers that have no drainage holes at all. I wonder if with this system there is no over watering, do the containers still need drainage? could I get away with adding some gravel rocks at the bottom of the containers? Or lifting the soil up an inch by using a net or something?