They aren't biting, right?

How long has this been happening?

If they haven't been there long, you can be pretty safe betting that they won't be permanent. Just something got off balance and their population boomed and soon it'll be back to normal. Probably.

I was expecting you to say they're red -- chiggers. And they bite. :p

My guess would be that you have curious baby spiders. :)

Thank you @Fori and @party_music50!

They don't bite and the first time I noticed these tiny bugs was three days ago. I'll observe them for a few weeks and hopeful their population will wane naturally, like Fori said. There has been extreme heat in my area in the past few days and I haven't watered this bed for two or three weeks (under the surface the bed remains wet, but the surface has been dry).

Thanks very much for your help! Now I feel a little less panicked :)

It might be a good idea to grab a magnifying glass and try to figure out what they are, just in case they are baby ticks or something nasty.

Linda

Could also be gnats if they fly around. Gnat populations infest certain plants and they will move around a lot if you disturb the plant. You can put up sticky traps for gnats and a good dose of pyrethrum often gets rid of them for good. Or insecticidal soap. There are some organic soil drenches you can use to destroy the larvae but if they've already hatched out and are feeding on your plants, probably not so great. They tend to hatch out in moist, humid conditions with a lot of decay. They can haunt the compost pile. You can also create gnat traps with cider vinegar if they are flying around.

If they continue to be bothersome I'd sprinkle the whole area with diatomateous earth. It won't hurt anybody but the insects... or whatever. It gets in their breathing tubes and joints and kills them,