In October I sewed (have sewn ?) sweet pea seeds

They have lived in my cold frame quite happily and are now around 6 inches
long.

The last few weeks they have started to look a bit pale and week. Help

What ought I to do? The frosts will not die down for a wee while now. Must
I feed them? I open the door whenever there is a nice day and always close
it at night

Ophelia
Scotland