As we're into late February I started sowing things in the greenhouse
and of course we promptly get a cold snap so I've got out the heaters
to keep everything cosy. Now some of the seed packets I have suggest
that temperatures of 18 - 20 degrees are required which seems
reasonable enough for a day time temperature in a greenhouse at this
time of year but what sort of temperatures can seeds survive over
night and still germinate or for that matter what sort of temperatures
can seedlings survive once they have germinated?

(or putting it another way am I going to have to spend a fortune on
paraffin in the next forthnight?)

JB