If you are into in-house planting, you'll love this fun idea: turn a light bulb into a tiny greenhouse.
Here's the detailed instruction (and make sure to look though the comments as well).
I am not sure what happens if / when a plant outgrows the bulb - but I guess there's a way to find a really tiny plant for it to grow inside for a long time.
Here are a few interesting takeaways from the comments:
- Will the plant need air?
If you give the plants an airtight house, you create a mini ecosystem and the water that's inside will eventually evaporate to the top, condensate on the glass, and fall back down like rain. It will keep doing that over and over, and you end up hardly ever having to water
- Do the plant grow, and does it stop growing?
The plants don't really grow much- a little bit, but they have stayed small enough to not outgrow the terrarium. A few of the little fern babies have doubled or tripled in size over the course of many months, but they were very tiny to begin with.
More greenhouse and planting gadgets: