What’s happen to my tomato leaves?

[Maggiethecat]

First time seeing this. A few of my seedlings have leaves turning white.

For example, one on the left seems fine unlike the one on the right.

They’re all watered the same but wonder if some have a nutrient deficiency?

I tend to get this when they've gotten a bit cold at night, is that a possibility? If that's the cause it's likely new leaves towards the centre will be fine and it'll grow fine after, but if they're not I'd look at a nutrient deficiency and perhaps repot with fresh compost, unlikely at this point though I think.

I’d say a rapid change in temperature - from frosty to sun in the greenhouse?

Sunburn? Keep going with them and those leaves should drop off anyway as the plant grows taller

Aaah! I’ve left them out a few days during the good weather and was slow to bring them back indoors in the evening when temps dropped quite a bit.

Could be sunburn too @Springhassprungthesunisout
I’ll just leave them inside by the window!