Those little pink plastic things are supposed to work good. If you want to make thousands of em for cheap go to Home Depot or Lowes. Go to the sprinkler section and get some of that skinny drip system hose (that goes from the main big hose to the plant). You can get 10' to 15' for cheap. It fits on just like the ones you would buy. We even had some in the garage. A foot would make you 100 minimum. And make sure you get the more rubbery hose if you do it. For the valve stem cap idea, a 22. shell casing or a pistol shell casing will work to.