Kale-Tuscan variety

Hi, I have planted some kale (cavelho Nero) seeds in the greenhouse to give them a start before planting out. They are approx 6inches tall now and  in individual 4inch pots and I am starting to harden them off by bringing them out each day.  Some of the leaves have gone a white(silvery white colour) all around the edges. Does anyone know whether this is due to either the cold or is it a watering poroblem?  Thanks.

Might be the change in temperature rather then the cold itself?  Kale (and other brassicas) doesn't need to be sowed in a greenhouse, its a tough plant.  Try re-sowing in pots/modules outside they'll be fine.  I've often shaken the snow off cavolo nero to get some fresh veg in the depths of winter.

Plant them quite deeply, and they like to be firm!