Beyond tender season obvious which plants need some warmth in winter cooled room?

Hi, We're getting our plant starts growing and wonder how many heating pads to buy given this polar vortexed deep freeze we're under? Do most plants need it, or just the tender season ones. I'm in zone 5, Canadian Kootenays and our grow room is cooler than rest of house, in spite of efforts to warm it from the rooms over the foundation. It was a recklessly constructed addition we found out later. Anyway, if there are any hardy plants needing some degrees up (warmth) for germination, please lemme know, with my warm thanks, OgreNick

I think many seeds, especially warm season crops, benefit from some added heat but most don't "need" it.  I have one heat pad that can almost do 4 seed trays.  I started 16 seed trays last year.  I just preferentially put the peppers and tomatoes on the heat pad and it all worked out.  If you have grow lights on them, they'll get some heat from the bulbs as well.

Thanks, it's just this "polar Vortex" is partic intense this year. Goin into big smoke (city) tmrw and will see what kind of deal i can get on heating pads. Happy & Happenin' Spring, OgreNick

Yes - definitely tired of this polar vortex!
Another trick I've used if things don't seem to be happening is to make sure I water with warm water - like 20C or so (70F).
Knowing the normal days to germination helps. I've had situations where the pots were past due and *nothing* had happened. I put them on the heat mat and the very next day I had sprouts.
Sometimes the issue is too cold at night, rather than too cold on "average". Since we heat with wood and the plants are on a window-sill, they can get pretty cool overnight. You may find you can save some power by only turning on the heat mats overnight. A timer can help if remembering is a chore.