This girl looks healthy, she sits in a big reservoir of food( the soil) and only needs water. Your girl has to do now " rooting Job" so it looks like for you as if she does not grow, But she builds roots atm. You can help her in watering with aloejuice/ solved in water,,, or using any " bigroots" but she will grow without that stuff too.....Young seedlings loove high rh so you can give her an " open dome" that means a plasticbottle halved, and poking some holes in it. So the plant has higher RH. Think about inventing in a humidifier, because Weed grows much better under optimal conditions
I let you a link t a VPD Chart , there you see wich RH you should reach in dependance of temperature and stage of grow
http://www.just4growers.com/media/23631/vpd_2degree.gif