Help! My cole seedlings are suddenly covered with aphids!

I am using jiffy pellets and have gotten and pretty good stand on most of the broccoli and cabbage seedlings. They are under lights in my kitchen and don't experience a wide variance of temperatures. So far the aphids haven't migrated to the tomato seedlings and I've taken the infected ones outside but we are in no way finsihed with frost or cold temps yet. I'm afraid if I try to hose them off they will all fall apart. Any ideas?

Maybe try a mist spray of mild neem solution? Just on some of them to be sure they respond well.

Wonder where those aphids came from?

Zeppy, I was wondering the same thing. I do have some neem, unopened, in my garden shed. It just started raining here and it's supposed to stay above freezing overnight, so I may leave them outside and try the neem tomorrow.
As an aside, we were given a prediction of an overnight low of 40 last night, and the weather channel website showed we had an overnight low of 42, but both of my thermometers showed and overnight low of 26 here, so the forecasts can't really be trusted.

I should say not. That's a big difference. Are you in a cold pocket?

Yes, very much so, on a low ridge with winds out of the north. Often our temps are the same or lower than Asheville, NC, 2 1/2 hours NE of here. But my house is facing south, so I get a lot of heat gain when the sun is out, so that's life. :-)

Try insecticidal soap...always works on aphids for me.

Thanks, I will get some of that.