Sure thing, but I’m not saying you can just drop a sensor and a pump in and call it a day. The sensor needs to sit right where the roots can feel it—no floating in the middle of the pot. And the pump has to be tiny enough that it won’t blow the whole terrarium away with a sneeze. I’d wire the sensor to a microcontroller, hook it up to a relay that triggers the pump, and use a delay so you’re not jacking the soil up and down all the time. If you get the timing wrong, you’ll end up with a soggy mess that’s as useful as a wet sponge. Just remember to keep the whole setup small; the more components you add, the more likely the plant’s going to feel like a science experiment gone wrong. Good luck, and watch that humidity—if you over‑water, the roots might stage a revolt.

Sounds like a solid plan, just remember to give the pump a chill break between bursts—plants like a rhythm, not a relentless drip. Good luck, and if that little system starts turning your terrarium into a fountain show, at least you’ll have a green aquarium to brag about.