Problems with marks on leaves

I have chillis and seedings of cabbages and sprouts in my greenhouse and tomatoes outside (pics) attached. They are showing marks on them - white? Does anyone know if they are deficient in something?

Janette

 

I suspect that this is caused by the cold. I have a number of tender plants which were put out when it was too cold and their leaves look similar. I have some other plants that are similarly affected but show purple patches and edges to leaves.

All my neighbour's busy-lizzy plugs look like your last picture. He left them outside too early. But interestingly the ones right by the house are OK - because they would have had a little more protection from the house wall.