I think generally pepper seeds take 7-14 days longer to germinate vs. tomato seeds, depending on the variety. My tomatoes can go out to the garden a good couple of weeks before my peppers because of soil temps so I always start them at the same time.

But no way are you going to get all of them to come up on the same day! It would be a miracle. ;) Use separate containers for peppers and tomatoes and then they can go to the lights as needed. Better yet, just start them under the lights.

Dave

Thanks for the response, digdirt. I know it would take a miracle for everything to come up at once : -). But the dark area I'm keeping the trays in for sprouting is a lot warmer than the area I've got set up with lights--since seed-spouting needs more heat than the growth that occurs under lights. And I'm trying to avoid the expense of a heating-pad. Space and cats are a concern, so they can't be the same place.
And I've got a lot more tomatoes than peppers, so separate containers wouldn't work in terms of space under the few lights I have either.
That's why I'm trying to figure out the best guess at staggering the sowing. Also, how long do purple tomatillos take to sprout?

Just got an order of tomato and pepper seeds today from TGS. They sent some info. that advises 6-8 weeks for tomato seeds and 8-10 weeks for peppers.

If I had known last year's germination success ahead of time, I would have started a few varieties about Christmas. Hoping for better germination this year, I'll start peppers about 3-1, and tomatoes about 3-15, for probable setting out 5-15, or perhaps 5-8 if the forecast looks good.