Should I pull up up

Hey first time grower here was wondering how cold is too cold .Temps dropping into 40s should I harvest

s long as it's not freezing the cold is ok. The humidity is important if it's 70-80% mold is imminent. If the forecast is sunshine no worries.
I'd go by how the plant looks. If it's throwing out white hairs it's not done. Wait until the caylxes swell up, hairs change color from white, and and the flowers are coated in resin. Don't worry about the resin turning amber can't wait that long this time of year plus I'm not a fan of it anyway.
If the limbs turn white or moldy and the flowers wilt, you find patches of grey mold in the flowers, or the weather man says frost you probably want to hack it down.

Thanks man this my first time planting since I was a teen 54 now lil rusty . Leaves starting to turn purple and has sticky flowers .
Think I mite have done good

They can survive a few frosts if you mulch around the base of the plants. I'd try to hold out as long as possible unless they look done.

To tell when they are done look at trichomes most should be cloudy.

Dam bunch of new terms to learn .
This has come a long way since back in the day