Seems like my #VerticalGardening is working... spinach, cabbages, lettuce and 2 tomatoes (just to experiment). The fertility is replenish by #composting kitchen scraps from an increasing amount of neighbors, which I plan to repay in food.
That's just a test, if it works properly I expect my yard walls to be covered by fall =D
the idea is not mine, you can find a good tutorial here: https://containergardening.wordpress.com/2011/09/07/bottle-tower-gardening-how-to-start-willem-van-cotthem/
My two modifications are:
* I don't cap the bottom bottle, I just put it in the soil (so I don't make a drainage hole neither;
* I tied each bottle separately because the weight was bending all the plastic (I have worst bottle than the guy I guess)