18/6 is perfectly fine. No seedling in nature Starts out at 24 hours of light. The plant will take off once it gets a good root system, it’s slow for a couple weeks the hits it’s stride, no worries. Miracle grow isn’t the devil, “the company is”, but you can use diluted MG, it will grow a plant. there is MUCH better out there but MG won’t hurt it. Just getting it in a good soil like ocean forest will feed it for over a month, with nothing but water. You don’t need to feed a seedling anyhow. And the amazon light isn’t actually 300 watts, the Chinese blurple lights all post wattage as actual when it’s “just like 300watts of a real light”. Grab a spider farmer sf1000. They’re on amazon. Good Quantum board, Won’t kill your electric bill, and a good start for 1 plant. Good luck.