Almost all the plants in my GH have these -- very tiny - almost look like small flies - they fly around the pots a little, but mostly I see them crawling around in the pots. What are they? And do I need to treat them?

From the limited description and behaviour it sounds like it could be fungus gnats. You might find this PDF of an article by an expert in fungus gnats useful:

http://www.ksre.ksu.edu/bookst...

@sooby oh, I hope that's not what it is -- the article makes it sound ominous. Yikes !

Try the potato disks on the soil and see if they attract any larvae, then that would be diagnostic. The larvae are fairly distinctive because they have a shiny black head. It's possible to identify the adult flying gnats if they're caught on sticky yellow cards, but they're very small and one would need to be able to see the vein pattern on the wings to ID them. If you have a camera that can take macros it might be possible.

@ sooby thank you. I'll try that. I read on line somewhere to sprinkle the soil with cinnamon and I did that last night -- all the plants in the GH. Also it said to put out a dish of sugar water (preferably a yellow dish). I put out two yellow and one blue. The yellow caught a bunch of them. Blue - they ignored.
The population seems to be way down this morning (but not all gone). I'll do the potato disk test. Thanks much,