Once you get a couple of these lids stuck together, you can never get them apart again. They trap the air between them, creating a vacuum of sorts. I got to thinking that you could easily use one of these to pot a plant. And you could use two of these to pot a plant, with a water trap in the bottom. The reasoning for the lower chamber is to catch the excess water that leaks through the soil. In doing so, you will keep from over watering your plants. Also, you will see just how much you are over-watering them, as you will be able to see the water trapped below. That water should dry up. And if there is no indication of moisture in the bottom, it may be time to water your plant again! We will call this contraption the "plant buddy" on account that you should not over water and kill whatever you grow in it.
What soil shall we use? Many smart people are finding that you can compost your own materials and come out with better soil than the stuff you pay high dollar for at your local home stores. We won't need a lot of soil for our small pot. Composting is science. You need the right amounts of the right materials, in the right temperatures to come out with good stuff. You may not want a rotting garbage can of waste in your yard while you experiment. Hence, the "My Little Composter". A see-through container where you can compost your materials in small amounts. My kids took an interest in this project which made me think that this would make a great future science project.
We started with three containers of various sizes, and the matching inter-locking bottom pieces.