Build Your Own Electronic Automatic Watering System

This short video demonstrates a DIY system for setting up automatic irrigation for a house plant.  I'm not convinced the soil-dryness sensor is sensitive enough to tailor for a finicky plant's water needs but this would probably work for a hardier, water loving plant.  The arrangement appears rather simple to set up if you have some electronics know-how.

Here's the full Instructable, via Lifehacker.