White widow autoflower

As you can see, my leafs don't look really healthy. It's either the fact that the soil was too wet for a couple of days cause my friends took care of it when I was away or it's because the humidity is so low. It's only on 36%, even though i bought an humidifier. The light was maybe too close to the plant as well in first week (30 cm I think, maybe less). I already highered the lamp to try and lower the humidity and to prevent the leaves from curling but idk if that's the solution... My first grow I never had problems with my humidity, maybe its because its colder outside now? I changed my ventilator as well, maybe that has an impact as well, but surely not that big? Any tips on: -What I should do to improve the leafs and prevent them from curling -What I should do to higher the humidity. As for nutrients, I mixed my soild with Biogrow (3g/l) when the plant was around day 3. I think this may have been too much too soon, but that's what they adviced on their site so I just went with it and afterwards I found out that you should try to wait untill your plant is a bit bigger.(I think)