That's hilarious, when I came up with that idea I thought I invented it... but I'm not surprised it's been done. Tim and I have both grown in SIPs, and with that method you make a trench near the bottom of the pot and fill it with time release nutes. My last grow I tried to build off of that idea by mixing time release nutes into the bottom 1/3 of the soil while using standard fabric pots. It worked pretty well, there were about a half dozen different strains and as would be expected they reacted a little differently, but for the most part I didn't have nute burn and they didn't show signs of being hungry either. The only thing I added during the grow was compost tea and cal-mag sometimes when watering. I will definitely continue experimenting with that.