yellow spots

this plant is about 13 days old. i've noticed these yellow spots developing on the leaves over the last couple days. not really sure what the problem is. i've only used water so far and i'm using MG soil. its not a heat issue i don't think as temps don't really go over 75. just wanting to know if anybody has ideas what the problem is and what i can do to make it better. thanks

is this one of you babies

got same probs got it on 4 out of my 10 plants seems to be affecting only my white widow strains none of other are affected also getting little holes in leave any idead let me know bud.
u grown from seed too?

searched all over carnt find Jack about it mind the pun!

my set up is

Soil/ batcomposte and perlite mix
no nutes with 10 plants under 400 watt HPS

Help getting worried never had probs before

over watering

i really don't think this is an issue with overwatering. i've only been giving them about a tablespoon of water every day, and the soil is always dry by the time i water.