Thanks again for advice. Soil is humid. If you look at the pics at the start of the thread the only one I feel it's in trouble it's the one in the first picture. The leaves are like wet paper. The other seedlings have some dry parts but the leaves don't bend too much.
The sun stays over the garden for just a couple of hours and I don't think with these clouds it's so strong, I can't feel it when I go out. Sure I'm not a little seedling
@florange sorry I will be back to you as soon as I can!