Cauli and Cabbage - New user looking for advise

Hi
I'm new to this forum, thought I might seek a bit of advise. All this is new to me; i've grown a few veg in the garden over the last two years with the kids and have this year securred a local allotment as an experiment to see if the enthusiasm from all the family continues when it's on a larger scale.
My Cauli and Cabbage seeds are growing well, probably 10cm high now. They were grown in the last two weeks in a heated propagator inside. i've had to move them out of the heater to make room for the tomato seedlings which I planted yesterday.
What I need to know is, what's the lowest temperatures that you'd trust to leaving them outside in a cold frame?
Cheers

WAYNESTROUT

My Cauli and Cabbage seeds are growing well, probably 10cm high now. They were grown in the last two weeks in a heated propagator inside.

I agree with MJ that you are too early.  Your cauliflower will probably head too early after suffering any sort of check to growth.   Giving you caulis not much bigger than a golf ball.   Keep 'em of course but I'd resow cauli in 6 or 8 weeks time if I were you.