White tips on leafs

Hi there. That substrate looks very very loose and airy. Does water pass thru it? If so your young seedling is struggling to catch water. Pour close to the stem for the next week or you can lightly compact your sub around the stem. As she's so young her stem is finding it hard to drink and can't pigment change under a light that's pushing her through photosynthesis. If this is the case, which looking at your sub it seems to be that. She'll grow out of it has her roots spread out to find liquid to match the speed of growth under PS. Good luck

Hola !!!! Solo genitica no tienes por que preocuparte. Cuida mucho a tu plantita suerte