How to Build a Terrarium
For a really self-sufficient indoor garden, try making a terrarium. Closed up in a large jar or aquarium, this kind of garden creates its own atmosphere and moisture. A terrarium needs only a good start in life, an occasional breath of fresh air, and, if necessary, the removal or addition of a plant here and there. This is a great project for kids:
Start with a clear glass or plastic bottle, dish, or aquarium.
A cover is optional. Make sure it's clean and dry.
Add a layer of aquarium gravel (up to 2 inches), cover with a thin layer of activated charcoal, and top with material to serve as a screen.
Plastic or a layer of sheet moss or landscape cloth acts as a screen to keep the soil from moving down into the gravel.
Add soil, and start planting.
Create your own little world by incorporating rocks, driftwood, tiny dinosaurs, or whatever accessories appeal to your imagination.