Answer: What you describe sound like fungus gnats. These critters feed and breed in decaying organic material such as potting soil. The easiest, most effective way to kill them off is to place a barrier between them and the moist potting soil. I've had really good success by simply watering my plants thoroughly and then covering the potting soil with plastic wrap. Leave the plastic wrap on for 7-10 days. Poke a small hole in the wrap if you need to water your plants, then cover it up again. The pests inside the plastic wrap will die off; those caught outside the wrap won't have a place to feed and breed and they will die off, too.
Best wishes with your indoor garden!
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