This project was from when I was living in an apartment and wanted to make a planter to hang on the balcony. I made this with some scrap yarn, a pencil, a empty 2 liter pop bottle and a sheet of paper towel.
First I made a "self-watering pot". Start by cutting a pop bottle in half. Then stuff the bottleneck with rolled up paper towel so that the ends go up into the bottle and down out of the opening. Invert the top half of the bottle and stick it into bottom half. Then plant a swiss chard seed (optional)
Then crochet this sock. Easier done than said. Its crocheted around and around (not rows) and both colors are attached but you only crochet one at a time. Its shaped by simple increases. Once its long enough I went back and forth to make the strap. I finished the top with a triangle edging and added a tassel to the bottom.
Here is how I hooked the strap to the railing