Indoor Soil Bugs

I suspect the "worm" you saw was one of two things - either a millipede or a soil centipede.

Soil CentipedeMy guess - which is a guess - is that if it was crawling faster than you could easily catch it, it was very likely a soil centipede. Nothing to worry about there; they are common soil-dwelling organisms and are predators, not plant feeders. And they don't reproduce very prolifically. Same thing with millipedes... although since millipedes have more legs - two pairs per body segment - the millipedes would be easier to catch if you wanted to.Milliped

Soil centipedes are actually beneficial...they live in the soil feeding on other soil-dwelling organisms such as fungus gnat larvae and pupae and are nothing to fret about. In other words, they don't get nearly as large or "adventurous" as the slightly more freakish house centipedes. And like their name suggests, they're exclusively soil-dwelling, so chances are good that unless you study your root ball for hours on end you will likely not frequently see the bugger.